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  • 51.
    Cats, Oded
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Jenelius, Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Beyond a complete failure: The impact of partial capacity degradation on public transport network vulnerability2018In: Transportmetrica B: Transport Dynamics, ISSN 2168-0566, Vol. 6, no 2, p. 77-96Article in journal (Refereed)
    Abstract [en]

    Disruptions in public transport networks (PTNs) often lead to partial capacity reductions rather than complete closures. This study aims to move beyond the vulnerability analysis of complete failures by investigating the impacts of a range of capacity reductions on PTN performance. The relation between network performance and the degradation of line or link capacities is investigated by establishing a vulnerability curve and related metrics. The analysis framework is applied to a full-scan analysis of planned temporary line-level capacity reductions and an analysis of unplanned link-level capacity reductions on the most central segments in the multi-modal rapid PTN of Stockholm, Sweden. The impacts of capacity reductions are assessed using a non-equilibrium dynamic public transport operations and assignment model. The nonlinear properties of on-board crowding, denied boarding, network effects and route choice result in non-trivial, generally convex, relations which carry implications on disruption planning and real-time management.

  • 52.
    Cats, Oded
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. Department of Transport and Planning, Delft University of Technology, Delft, The Netherlands .
    Jenelius, Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Planning for the Unexpected: The Value of Reserve Capacity for Public Transport Network Robustness2015In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 81, p. 47-61Article in journal (Refereed)
    Abstract [en]

    Public transport networks (PTN) are subject to recurring service disruptions. Most studies of the robustness of PTN have focused on network topology and considered vulnerability in terms of connectivity reliability. While these studies provide insights on general design principles, there is lack of knowledge concerning the effectiveness of different strategies to reduce the impacts of disruptions. This paper proposes and demonstrates a methodology for evaluating the effectiveness of a strategic increase in capacity on alternative PTN links to mitigate the impact of unexpected network disruptions. The evaluation approach consists of two stages: identifying a set of important links and then for each identified important link, a set of capacity enhancement schemes is evaluated. The proposed method integrates stochastic supply and demand models, dynamic route choice and limited operational capacity. This dynamic agent-based modelling of network performance enables to capture cascading network effects as well as the adaptive redistribution of passenger flows. An application for the rapid PTN of Stockholm, Sweden, demonstrates how the proposed method could be applied to sequentially designed scenarios based on their performance indicators. The method presented in this paper could support policy makers and operators in prioritizing measures to increase network robustness by improving system capacity to absorb unexpected disruptions.

  • 53.
    Cats, Oded
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Loutos, Gerasimos
    KTH, School of Architecture and the Built Environment (ABE), Transport Science.
    Evaluating the added-value of online bus arrival prediction schemes2016In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 86, p. 35-55Article in journal (Refereed)
    Abstract [en]

    Online predictions of bus arrival times have the potential to reduce the uncertainty associated with bus operations. By better anticipating future conditions, online predictions can reduce perceived and actual passenger travel times as well as facilitate more proactive decision making by service providers. Even though considerable research efforts were devoted to the development of computationally expensive bus arrival prediction schemes, real-world real-time information (RTI) systems are typically based on very simple prediction rules. This paper narrows down the gap between the state-of-the-art and the state-of-the-practice in generating RTI for public transport systems by evaluating the added-value of schemes that integrate instantaneous data and dwell time predictions. The evaluation considers static information and a commonly deployed scheme as a benchmark. The RTI generation algorithms were applied and analyzed for a trunk bus network in Stockholm, Sweden. The schemes are assessed and compared based on their accuracy, reliability, robustness and potential waiting time savings. The impact of RTI on passengers waiting times are compared with those attained by service frequency and regularity improvements. A method which incorporates information on downstream travel conditions outperforms the commonly deployed scheme, leading to a 25% reduction in the mean absolute error. Furthermore, the incorporation of instantaneous travel times improves the prediction accuracy and reliability, and contributes to more robust predictions. The potential waiting time gains associated with the prediction scheme are equivalent to the gains expected when introducing a 60% increase in service frequency, and are not attainable by service regularity improvements.

  • 54.
    Cats, Oded
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS. Department of Transport and Planning, Delft University of Technology, Delft, The Netherlands .
    Loutos, Gerasimos
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Real-Time Bus Arrival Information System: An Empirical Evaluation2016In: Journal of Intelligent Transportation Systems, ISSN 1547-2450, Vol. 20, no 2, p. 138-151Article in journal (Refereed)
    Abstract [en]

    The provision of real-time information concerning bus arrival times could potentially reduce the uncertainty associated with public transport trips and improve the overall level-of-service. In addition, real-time predictions might enable operators to apply proactive control strategies. Even though considerable research efforts were devoted to the development of bus arrival prediction schemes, there is lack of knowledge on the performance of real-world operational systems. This paper aims to investigate the performance of a commonly deployed real-time information generation scheme. A conventionally used scheme is implemented and evaluated based on an empirical analysis. Performance metrics concerning the prediction error accuracy and reliability and their impact on expected waiting time were formulated from both passengers’ and operators’ perspective. The real-time information generator was applied on the trunk line network in Stockholm, Sweden. The accuracy and reliability of the prediction scheme was analysed by comparing the generated predictions against vehicle positioning data. This scheme was found to systematically underestimate the remaining waiting time by 6.2% on average. The provision of real-time information yields a waiting time estimate that is more than twice closer to the actual waiting times than the timetable is. This difference in waiting time expectations is equivalent to 30% of the average waiting time.

  • 55.
    Cats, Oded
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. Delft University of Technology, The Netherlands.
    Susilo, Yusak O.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Reimal, T.
    The prospects of fare-free public transport: evidence from Tallinn2016In: Transportation, ISSN 0049-4488, E-ISSN 1572-9435, p. 1-22Article in journal (Refereed)
    Abstract [en]

    The subsidy level of public transport systems varies considerably among systems worldwide. While limited-scale free-fare public transport (FFPT) services such as limited campaigns and fare evasion for special groups or specific services are prevalent, there is only limited evidence on the consequences of introducing a full-fledged FFPT. The case of Tallinn, Estonia offers a full-scale experiment that provides a unique opportunity to investigate the impacts of FFPT. This study examines travel pattern changes based on individual travel habit survey shortly before and almost 1 year after the introduction of FFPT policy in Tallinn based on interviews and travel diaries of a random sample of 1500 household. We analyse modal shift effects and whether they are driven by trip generation or trip substitution, travel attitudes and satisfactions as well as impacts on equity, employment prospects, and trip destination choices. Almost a year after the introduction of FFPT, public transport usage increased by 14 % and there is evidence that the mobility of low-income residents has improved. The effect of FFPT on ridership is substantially lower than those reported in previous studies due to the good level of service provision, high public transport usage and low public transport fees that existed already prior to the FFPT.

  • 56.
    Cats, Oded
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. Delft University of Technology, Netherlands.
    Wang, Q.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science.
    Zhao, Y.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science.
    Identification and classification of public transport activity centres in Stockholm using passenger flows data2015In: Journal of Transport Geography, ISSN 0966-6923, E-ISSN 1873-1236, Vol. 48, p. 10-22, article id 1735Article in journal (Refereed)
    Abstract [en]

    Urban geography could be characterized by analysing the patterns that describe the flows of people and goods. Measuring urban structures is essential for supporting an evidence-based spatial planning policy. The objective of this study is to examine how the spatial-temporal distribution of public transport passenger flow could be used to reveal urban structure dynamics. A methodology to identify and classify centres based on mobility data was applied to Metropolitan Stockholm in Sweden using multi-modal public transport passenger flows. Stockholm is known for its long-term monocentric planning with a dominant central core and radial public transport system. Strategic nodes along its radial public transport system have been a focus for development of sub-centres. Although the regional planning policy embraces a shift towards a polycentric planning policy, the results indicate that this has not been realized insofar.

  • 57.
    Cats, Oded
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. Delft University of Technology, Netherlands.
    West, Jens
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Eliasson, Jonas
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    A dynamic stochastic model for evaluating congestion and crowding effects in transit systems2016In: Transportation Research Part B: Methodological, ISSN 0191-2615, E-ISSN 1879-2367, Vol. 89, p. 43-57Article in journal (Refereed)
    Abstract [en]

    One of the most common motivations for public transport investments is to reduce congestion and increase capacity. Public transport congestion leads to crowding discomfort, denied boardings and lower service reliability. However, transit assignment models and appraisal methodologies usually do not account for the dynamics of public transport congestion and crowding and thus potentially underestimate the related benefits. This study develops a method to capture the benefits of increased capacity by using a dynamic and stochastic transit assignment model. Using an agent-based public transport simulation model, we dynamically model the evolution of network reliability and on-board crowding. The model is embedded in a comprehensive framework for project appraisal.A case study of a metro extension that partially replaces an overloaded bus network in Stockholm demonstrates that congestion effects may account for a substantial share of the expected benefits. A cost-benefit analysis based on a conventional static model will miss more than a third of the benefits. This suggests that failure to represent dynamic congestion effects may substantially underestimate the benefits of projects, especially if they are primarily intended to increase capacity rather than to reduce travel times.

  • 58.
    Cats, Oded
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    West, Jens
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. SWECO, Sweden.
    Eliasson, Jonas
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Appraisal of increased public transport capacity: The case of a new metro line to Nacka, Sweden2014Report (Other academic)
  • 59.
    Cats, Oded
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport planning, economics and engineering.
    Zhang, Chen
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport planning, economics and engineering.
    Nissan, Albania
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport planning, economics and engineering.
    Empirical evaluation of an on-street parking pricing scheme in the city center2015Conference paper (Refereed)
    Abstract [en]

    Parking pricing policies can be used as a policy instrument to steer the parking market and reduce the externalities caused by traffic in general and parking in particular. A more efficient management of parking demand can improve the utilization of the limited parking capacity at high-demand areas. Even though parking policies are often a topic of public debate, there is lack of systematic empirical analysis of various parking measures. This paper proposes a methodology to empirically measure and evaluate the impacts of on-street parking policies. The utilization of on-street parking demand is computed based on transaction data from 70 ticket vending machines which is calibrated using floating car films. Measures of parking utilization such as occupancy and its temporal variation, throughput, parking duration and turnover are compared prior and following the introduction of a new parking scheme in the center of Stockholm, Sweden, in September 2013. The results indicate that the policy led to a reduction in parking occupancy although it did not yield the 85% occupancy level objective. Furthermore, the price increase has contradictory effects on throughput and turnover due to the interaction between parking occupancy and duration. The results also question the transferability of price elasticity. It is thus recommended to consider multiple measures of parking utilization when carrying out policy evaluation. 

  • 60.
    Cats, Oded
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. Delft University of Technology, Netherlands.
    Zhang, Chen
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Nissan, Albania
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Survey methodology for measuring parking occupancy: Impacts of an on-street parking pricing scheme in an urban center2016In: Transport Policy, ISSN 0967-070X, E-ISSN 1879-310X, Vol. 47, p. 55-63Article in journal (Refereed)
    Abstract [en]

    Parking pricing policies can be used as a policy instrument to steer the parking market and reduce the externalities caused by traffic in general and parking in particular. A more efficient management of parking demand can improve the utilization of the limited parking capacity in high-demand areas. Even though parking policies are often a topic of public debate, there is lack of systematic empirical analysis of various parking measures. This paper proposes a survey methodology to empirically measure the impacts of on-street parking policies based on automated parking transaction data. Parking performance is computed based on data available from ticket vending machines calibrated using floating car films. The survey method allows comparing parking occupancy including its temporal variations, allowing the analysis of the accumulated utilization pattern. Average and maximum parking occupancy levels, throughput, parking duration and total fare collection are compared prior and following the introduction of a new parking scheme for visitors to Stockholm inner-city, Sweden. The results indicate that the policy fulfilled its objective to increase the ease of finding a vacant parking place in the central areas and even resulted with underutilized parking spaces.

  • 61.
    Cebecauer, Matej
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Buzna, Ľ.
    A versatile adaptive aggregation framework for spatially large discrete location-allocation problems2017In: Computers & industrial engineering, ISSN 0360-8352, E-ISSN 1879-0550, Vol. 111, p. 364-380Article in journal (Refereed)
    Abstract [en]

    We propose a versatile concept of the adaptive aggregation framework for the facility location problems that keeps the problem size in reasonable limits. Most location-allocation problems are known to be NP-hard. Thus, if a problem reaches the critical size, the computation exceeds reasonable time limits, or all computer memory is consumed. Aggregation is a tool that allows for transforming problems into smaller sizes. Usually, it is used only in the data preparation phase, and it leads to the loss of optimality due to aggregation errors. This is particularly remarkable when solving problems with a large number of demand points. The proposed framework embeds the aggregation into the solving process and it iteratively adjusts the aggregation level to the high quality solutions. To explore its versatility, we apply it to the p-median and to the lexicographic minimax problems that lead to structurally different patterns of located facilities. To evaluate the optimality errors, we use benchmarks which can be computed exactly, and to explore the limits of our approach, we study benchmarks reaching 670,000 demand points. Numerical experiments reveal that the adaptive aggregation framework performs well across a large range of problem sizes and is able to provide solutions of higher quality than the state-of-the-art exact methods when applied to the aggregated problem.

  • 62. Chen, C.
    et al.
    Ma, J.
    Susilo, Yusak
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Liu, Y.
    Wang, M.
    The promises of big data and small data for travel behavior (aka human mobility) analysis2016In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 68, p. 285-299Article in journal (Refereed)
    Abstract [en]

    The last decade has witnessed very active development in two broad, but separate fields, both involving understanding and modeling of how individuals move in time and space (hereafter called "travel behavior analysis" or "human mobility analysis"). One field comprises transportation researchers who have been working in the field for decades and the other involves new comers from a wide range of disciplines, but primarily computer scientists and physicists. Researchers in these two fields work with different datasets, apply different methodologies, and answer different but overlapping questions. It is our view that there is much, hidden synergy between the two fields that needs to be brought out. It is thus the purpose of this paper to introduce datasets, concepts, knowledge and methods used in these two fields, and most importantly raise cross-discipline ideas for conversations and collaborations between the two. It is our hope that this paper will stimulate many future cross-cutting studies that involve researchers from both fields.

  • 63. Chen, M.
    et al.
    Wang, D.
    Sun, Y.
    Liu, Chengxi
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Bai, Z.
    Service evaluation of public bicycle scheme from a user perspective2017In: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, Vol. 2634, p. 28-34Article in journal (Refereed)
    Abstract [en]

    In late 2005, in an attempt to solve the last-mile problem, China started implementing public bikesharing programs. The effort quickly grew to a massive scale. An estimated 400,000 public bicycles now are in use in China, which is more than in all other countries that have implemented public bicycle schemes (PBSs). As with any emerging service that develops rapidly, an understanding of user behavior and satisfaction is lacking. Factors that influence the frequency of public bicycle use were studied in Hangzhou, China. Online and intercept surveys were conducted with PBS users. Willingness to use the PBS as well as satisfaction with and concerns about the PBS were investigated. Analysis of variance was conducted to identify the six factors that affect a user's decision to rent: car ownership, bicycle ownership, travel purpose, having or lacking familiarity with the rental process, level of satisfaction with the PBS, and level of familiarity with the distribution of docking stations. Binary logistic regression analysis was used to elucidate details of key factors in the group of most frequent users-that is, survey respondents who did not own a car, rented a bicycle primarily for shopping or going out for business, and were familiar with the rental process and the distribution of docking stations. Based on study findings, advice is presented for implementing policy in developing countries. Suggestions include publicizing the PBS more, attracting more commuters to bicycling to reduce congestion, enhancing the accessibility of docking stations to accommodate more potential users, and improving bicycle quality to encourage more participation and make it easier for elderly citizens to participate.

  • 64.
    Chengxi, Liu
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Understanding the Impacts of Weather and Climate Change on Travel Behaviour2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Human behaviour produces massive greenhouse gas emissions, which trigger climate change and more unpredictable weather conditions. The fluctuation of daily weather corresponds to variations of everyday travel behaviour. This influence, although is less noticeable, can have a strong impact on the transport system. Specifically, the climate in Sweden is becoming warmer in the recent 10 years. However, it is largely unknown to what extent the change of travel behaviour would respond to the changing weather. Understanding these issues would help analysts and policy makers incorporate local weather and climate within our policy design and infrastructure management.

    The thesis contains eight papers exploring the weather and climate impacts on individual travel behaviour, each addressing a subset of this topic. Paper I explores the weather impact on individual’s mode choice decisions. In paper II and III, individual’s daily activity time, number of trips/trip chains, travel time and mode shares are jointly modelled. The results highlight the importance of modelling activity-travel variables for different trip purposes respectively. Paper IV develops a namely nested multivariate Tobit model to model activity time allocation trade-offs. In paper V, the roles of weather on trip chaining complexity is explored. A thermal index is introduced to better approximate the effects of the thermal environment. In paper VI, the role of subjective weather perception is investigated. Results confirm that individuals with different socio-demographics would have different subjective weather perception even given similar weather conditions. Paper VII derives the marginal effects of weather variables on transport CO2 emissions. The findings show more CO2 emissions due to the warmer climate in the future. Paper VIII summaries the existing findings in relations between weather variability and travel behaviour, and critically assesses the methodological issues in previous studies. 

  • 65.
    Chengxi, Liu
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Susilo, Yusak O.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Anders, Karlström
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, System Analysis and Economics.
    Estimating changes in transport CO2 emissions due to changes in weather and climate in SwedenManuscript (preprint) (Other academic)
    Abstract [en]

    There is a considerable body of studies on the relationship between daily transport activities and CO2 emissions. However, how these emissions vary in different weather conditions within and between the seasons of the year is largely unknown. Because individual activity–travel patterns are not static but vary in different weather conditions, it is immensely important to understand how CO2 emissions vary due to the change of weather. Using Swedish National Travel Survey data, with emission factors calculated through the European emission factor model ARTEMIS, this study is a first attempt to derive the amount of CO2 emission changes subject to the change of weather conditions. A series of econometric models was used to model travel behaviour variables that are crucial for influencing individual CO2 emissions. The marginal effects of weather variables on travel behaviour variables were derived. The results show an increase of individual CO2 emissions in a warmer climate and in more extreme temperature conditions, whereas increasing precipitation amounts and snow depths show limited effects on individual CO2 emissions. It is worth noting that the change in CO2 emissions in the scenario of a warmer climate and a more extreme temperature tends to be greater than the sum of changes in CO2 emissions in each individual scenario. Given that a warmer climate and more extreme weather could co-occur more frequently in the future, this result suggests even greater individual CO2 emissions than expected in such a future climate.

  • 66.
    Chengxi, Liu
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Susilo, Yusak O.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Anders, Karlström
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, System Analysis and Economics.
    Weather Variability and Travel Behaviour - What Do We Know and What Do We Not KnowManuscript (preprint) (Other academic)
    Abstract [en]

    Given that severe weather conditions is becoming more and more frequent, understanding the roles of weathers in influencing individual’s daily activity-travel pattern is important. Whilst some of previously rare events, such as heavy rain, unpredictable snow, higher temperature, less clear differences between seasons etc., would become more common, it is still largely unknown how individual would change and adapt their travel pattern in future climate conditions. Because of this concern, the number of researches on weather and travel behaviour has been increased dramatically in the recent decades. Most of those empirical evidences, however, have not been adopted in cost-benefit analysis (CBA), which serves as the main tool for policy evaluation and project selection by stakeholders. This study summarizes the existing findings in relations between weather variability and travel behaviour, and critically assesses the methodological issues in those studies. Several further research directions are identified and suggested for bridging the gap between empirical evidence and current practice in CBA.

  • 67.
    Chengxi, Liu
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Susilo, Yusak O.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Karlström, Anders
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, System Analysis and Economics.
    Jointly modelling individual’s daily activity-travel time use andmode share by a nested multivariate Tobit model system2015In: Transportation Research Procedia: 21st International Symposium on Transportation and Traffic Theory, Elsevier, 2015, Vol. 9, p. 71-89Conference paper (Refereed)
    Abstract [en]

    Understanding mechanisms underlie the individual’s daily time allocations is very important to understand the variability ofindividual’s time-space constraints and to forecast his/her daily activity participation. At most of previous studies, activity timeallocation was viewed as allocating a continuous quantity (daily time budget) into multiple discrete alternatives (i.e. variousactivities and trips to engage with). However, few researches considered the influence of travel time that needs to be spent onreaching the activity location. Moreover, travel time itself is influenced by individuals’ mode choice. This can lead to an over- orunder-estimation of particular activity time location. In order to explicitly include the individual’s travel time and mode choiceconsiderations in activity time allocation modelling, in this study, a nested multivariate Tobit model is proposed. This proposedmodel can handle: 1. Corner solution problem (i.e. the present of substantial amount of zero observations); 2. Time allocationtrade-offs among different types of activities (which tends to be ignored in previous studies); 3. Travel is treated as a deriveddemand of activity participation (i.e. travel time and mode share are automatically censored, and are not estimated, ifcorresponding activity duration is censored). The model is applied on a combined dataset of Swedish national travel survey(NTS) and SMHI (Swedish Meteorological and Hydrological Institute) weather record. Individuals’ work and non-work activitydurations, travel time and mode shares are jointly modelled as dependent variables. The influences of time-locationcharacteristics, individual and household socio demographics and weather characteristics on each dependent variable areexamined. The estimation results show a strong work and non-work activity time trade-offs due to the individual’s time-spaceconstraints. Evidences on a potential positive utility of travel time added on non-work activity time allocation in the Swedish case,are also found. Meanwhile, the results also show a consistent mode choice preference for a given individual. The estimatednested multivariate Tobit model provides a superior prediction, in terms of the deviation of the predicted value against the actualvalue conditional on the correct prediction regarding censored and non-censored, compared to mutually independent Tobitmodels. However, the nested multivariate Tobit model does not necessarily have a better prediction for model componentsregarding non-work related activities.

  • 68.
    Chengxi, Liu
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Susilo, Yusak O.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Nursitihazlin, Ahmad Termida
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Subjective perception towards uncertainty on weather conditions and its impact on out-of-home leisure activity participation decisionsManuscript (preprint) (Other academic)
    Abstract [en]

    Weather is fundamentally a ‘subjective’ perception rather than an objective measure that affects individual’s everyday travel decisions. This study uses data from a four-wave travel diary survey and aims to answer two research questions, i.e. 1. How individuals from different socio-demographic groups perceive weather. 2. How subjective weather perceptions affect individuals’ leisure activity participation decisions. Subjective weather perception and leisure activity participation are modelled in panel static/dynamic ordered Probit models. The results show that the reference thermal environment in general corresponds to the historical mean of the thermal environment. The effects of objective weather measures on subjective weather perception vary substantially between individuals. Moreover, the effect of subjective weather perception on leisure activity participation is non-linear and asymmetric. Only “very bad weather” and “very good weather” significantly influence the leisure activity participation. The effect of “very bad weather” also varies significantly between individuals. The intra-individual heterogeneity in the effect of “very good weather” has a smaller magnitude than that in the effect of “very bad weather”.

  • 69.
    Dahlberg, Anton
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Jangenstål, Ludvig
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Förutsättningar för ökad metervikt och axellast på Malmbanan2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    LKAB intends to increase the production of iron ore in the upcoming years. To prevent problems with

    the capacity along Malmbanan (The Iron Ore Line) an increase in the maximum permissible axle load

    is required. The first step is an increase from 30 ton to 32.5 ton. The vision is to increase the axle load

    in 4 steps of 32.5 - 35 - 37.5 – 40 ton, where an axle load of 40 ton is the final goal. The report deals

    with the influence of an increased axle load for each track component. This is in order to present the

    deterioration of the track quality when the axle load is increased. Different methods of track

    maintenance and reinforcements will also be discussed.

    The work is focused on the southern circuit of Malmbanan. Track conditions on individual track

    sections will not be considered. The work only includes the track structure i.e. signaling systems and

    power supply systems will not be considered. Economical calculations of reinforcement and

    maintenance activities is left for future investigations.

    The working process has included a literature study, field study, computational study and an

    interview study. This has led to an assessment of to what extent each track component is affected by

    an increase in maximum permissible axle load.

    The rail will be exposed to a higher amount of wear, an increased risk for rail defects and plastic

    deformation of the rail head. Rail damage is most easily prevented by rail grinding and rail lubrication

    in sharp curves. More extensive measures are to replace the rail with a stronger rail steel or replace

    with a larger rail profile.

    The rail fastenings will be affected by higher track forces and are particularly exposed in sharp

    curves. The rail fastening systems has to be replaced gradually when increasing the permissible axle

    load. The only fastening device, in use today, that will be approved for 40 ton axle load is the Fastclip

    and the strongest e-clips with plastic rail pads.

    The lifetime of the sleepers will be shortened with an increased axle load. A critical factor is the

    bending moment at the position of the rail and in the middle of the sleeper. According to the

    performed calculations all sleeper models eventually have to be replaced, except sleeper model A22.

    However, there is a lack of knowledge about the sleeper strength for some models. Strength tests for

    each specific sleeper model should therefore be carried out.

    It is recommended that a research study is performed to gain knowledge about the track position

    and model for all the fastening systems and sleepers along the track. This in order to ease future

    track upgrades.

    A higher axle load leads to an accelerated deterioration of the ballast. Ballast cleaning is

    recommended in the near future to reduce the rate of ballast contamination. The ballast thickness

    should not be less than 50 cm, according to performed calculations.

    An increased axle load will cause an increased need for maintenance of the track substructure.

    Reinforcements have to be carried out on several bridges and culverts. This also applies to the

    geotechnics, which is mainly reinforced by pressure banks at track sections with poor subgrade. A

    complete investigation of the bearing capacity of the track subgrade should be performed. This in

    order to find track sections with insufficient bearing capacity. An investigation of the load carrying

    capacity for all bridges along the southern circuit of Malmbanan should also be performed.

  • 70.
    Deng, Qichen
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    A Constant Spacing Policy for Heavy-Duty VehiclePlatoon Disaggregation at Highway Off-RampManuscript (preprint) (Other academic)
    Abstract [en]

    Platooning heavy-duty vehicles (HDVs) on highways using cooperative adaptive cruise control (CACC) can significantly reduce fuel consumption and improve traffic throughput.HDVs operating with small inter-vehicle distances reduce aerodynamic resistance considerably. However, HDV platoons can also have negative impacts on traffic flow when they hinder lane changing at highway off-ramps. This study investigates whether disaggregation of HDV platoons benefits traffic flow at highway off-ramps. A modified constant spacing policy is applied forHDV platoon disaggregation. The feasible region of the CACCparameters is derived based on an analysis of asymptotic stability, driving safety, and HDV acceleration and braking capabilities.The proposed HDV platoon disaggregation strategy at highway off-ramps is implemented and simulated in a microscopic traffic simulation package. According to the simulation outcomes, a disaggregation of HDV platoons at off-ramps leads to significant average speed improvements at high traffic flow rates.

  • 71.
    Deng, Qichen
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    A General Simulation Framework for Modeling and Analysis of Heavy-Duty Vehicle Platooning2016In: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, Vol. 17, no 11, p. 3252-3262Article in journal (Refereed)
    Abstract [en]

    Platooning heavy-duty vehicles (HDVs) on a highway is a method for improving energy and transport efficiency. On one hand, HDV platoon driving in small intervehicle distances could increase highway capacity; on the other hand, HDVs traveling in small intervehicle distances experience significant air-drag reduction and, therefore, improve fuel efficiency. However, although the majority of research has been conducted on the development of platoon systems, very few studies have focused on quantification of the impacts of HDV platooning on traffic flow. This paper initializes a simulation framework to facilitate the study of HDV platooning and establishes the corresponding concept and operations. The longitudinal driving behaviors of HDV platoons are modeled in detail, considering the acceleration capability of an HDV. The proposed framework is applied on three experimental cases: the first case is to study the impacts of HDV platooning on traffic flow and the second and third cases are about the influence of traffic on HDV platoon formation. In the first case, simulation outcomes show that the increasing percentage of HDV platooning in traffic flow generally results in more dramatic improvements on traffic efficiency, while preserving traffic safety for passenger vehicles. In the second and third cases, for the HDV platoon formation, deceleration of the first HDV to a low speed during platoon formation will increase the formation time to a large extent in medium and heavy traffic.

  • 72.
    Deng, Qichen
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    A General Simulation Framework for Modeling andAnalysis of Heavy-Duty Vehicle PlatooningManuscript (preprint) (Other academic)
    Abstract [en]

    Platooning heavy-duty vehicles (HDVs) on highway is a method of improving energy and transport efficiency. On the one hand, HDV platoon driving in small inter-vehicle distances could increase highway capacity; on the other hand, HDVs traveling in small inter-vehicle distances experience significant air -drag reduction and therefore, improve fuel efficiency. However, the majority of research has been conducted on the development of platoon system, very few studies have focused on quantification of the impacts of HDV platooning on traffic flow. This paper initializes a simulation framework to facilitate the study of HDVplatooning and establishes corresponding concept and operations.The longitudinal driving behaviors of HDV platoons is modeled in detail considering the acceleration capability of HDV. The proposed framework is applied in three experimental cases, the first case is to study the impacts of HDV platoons on traffic flow, and the second and third cases are about the influence of traffic on HDV platoon formation. In the first case, simulation outcomes show that increasing percentage of HDV platooning in traffic flow generally results in more dramatic improvements in traffic efficiency while preserving traffic safety for passenger vehicles; in the second and third cases, for the HDV platoon formation, deceleration of the first HDV in low speed during platoon formation will increase the formation time to a large extent in medium and heavy traffic.

  • 73.
    Deng, Qichen
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Heavy-Duty Vehicle Platooning: Modeling and Analysis2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Coupled with the growth of world economy, the demand for freight transport has escalated and will continue to do so. As the traffic intensity increases, the pressure on infrastructure, energy usage and environment becomes higher than ever. Meanwhile, the number of traffic accidents is also increasing year by year as a result. Heavy-duty vehicle (HDV) platooning makes a group of HDVs driving closely after each other.It is one potential solution to improve transport efficiency, traffic safety and fuel economy. Even though there have been extensive studies on the platooning system and corresponding fuel saving, some of the research areas, such as coordination strategies of platooning, platoon operations and the impacts of HDV platooning on trafficflow are still left open. Under a futuristic scenario where a large number of HDVswill be operating in one or several platoons on highway, how to group HDVs intoa platoon and how to select spacing policies for HDV platooning are essential forautomobile manufacturers, fleet operators and transport planners. Therefore, theformation strategies and operations of HDV platoons, as well as the impacts of HDVplatooning on traffic flow have to be carefully investigated.

    This thesis presents contributions to the modeling of HDV platooning and simulationof HDV platoon operations. The focus lies mainly on analytical formulation ofspeed-density relation of mixed traffic flow and development of simulation frameworkfor study of HDV platooning. On the one hand, a three-regime speed-density relationis proposed to describe the mixed traffic flow consisting of HDVs and passengercars. The proposed speed-density relation incorporates percentage of HDVs, trafficdensity and spacing policy of HDV platoons as input variables and delivers aggregatehighway velocity as output. By comparing the traffic throughput of no HDV platooningscenario, grouping HDVs into platoon using constant vehicle spacing policy orconstant time gap policy results in significant improvement in highway capacity. On the other hand, a simulation framework is developed for implementation of differentHDV platoon operations. The platoon formation of two HDVs and disaggregation ofa five-HDV platoon at off-ramp are simulated on a two-lane highway. The simulationoutcomes show that HDV platoon formation is more favorable in light and mediumtraffic; disaggregation of a long HDV platoon at off-ramp improves the averagespeed of passenger vehicles considerably at high traffic flow rate.

  • 74.
    Deng, Qichen
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Boughout, Wilco
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    The Impacts of Heavy-Duty Vehicle Platoon Spacing Policy on Traffic FlowManuscript (preprint) (Other academic)
    Abstract [en]

    Spacing policy of heavy-duty vehicle (HDV) platoons determines the inter-vehicle distance between HDVs in steady state. It plays an important role in traffic throughput. For example, an HDV platoon with small spacing policies saves space on the highway so that it can accommodate more vehicles. Therefore, the traffic efficiency and highway capacity may be improved by applying small spacing policies on HDV platoons. Conversely, an HDVplatoon with larger spacing policies requires more space on highways and thus has a negative impact on capacity.This paper specifically focuses on two commonly used spacing policies in HDV platooning, constant vehicle spacing (CVS) and constant time gap (CTG) and investigates respective impacts on traffic flow. The speed-density relation of mixed traffic flow is formulated as a function of traffic density, the percentage of HDVs on highway and spacing policy of HDV platoon. In order to investigate the effects of HDV platooning to vehicle interaction, the speed-density relation is derived from car-following model. Numerical results show that HDV platooning with CVSpolicy yields the most significant improvement in highway capacity, compared with no HDV platooning scenario and HDV platooning with CTG policy. However, it has worse performance in heavily congested traffic flows thanCTG policy. A mixed CVS-CTG policy is therefore proposed in this study, in order to combine the benefits fromCVS and CTG policies to traffic flow. This mixed spacing policy could be a promising alternative to the single spacing policy.

  • 75.
    Deng, Qichen
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Ma, Xiaoliang
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    A fast algorithm for planning optimal platoon speeds on highway2014In: Elsevier IFAC Publications / IFAC Proceedings series, ISSN 1474-6670, Vol. 19, p. 8073-8078Article in journal (Refereed)
    Abstract [en]

    To meet policy requirements on increased transport energy efficiency and reduced emissions, smart control and management of vehicles and fleets have become important for the development of eco-friendly intelligent transportation systems (ITS). The emergence of new information and communication technologies and their applications, particularly vehicle-to-vehicle and vehicle-to-infrastructure communication, facilitates the implementation of autonomous vehicle concepts, and meanwhile serves as an effective means for control of vehicle fleet by continuously providing support and guidance to drivers. While convoy driving of trucks by longitudinal automation could save 5-15% of fuel consumption due to the reduction of airdrag resistance, this study attempts to investigate the energy saving potential of truck platoons by intelligent speed planning. Assuming that real-time traffic information is available because of communication, an efficient speed control algorithm is proposed based on optimal control theory. The method is faster than the conventional dynamic programming approach and hence applied in the study to analyze energy saving potential of simple platoon operations including acceleration and deceleration. The numerical result shows significant improvement on energy saving due to speed planning during platooning. It can be further applied for more complex platooning operations.

  • 76.
    Dharmowijoyo, Dimas B. E.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Susilo, Yusak O.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Karlström, Anders
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, System Analysis and Economics.
    Analysing the complexity of day-to-day individuals’ activity-travel pattern using Multi-dimensional Sequence Alignment Method: A case study in Bandung Metropolitan Area, IndonesiaManuscript (preprint) (Other academic)
  • 77.
    Dharmowijoyo, Dimas B. E.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Susilo, Yusak O.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Karlström, Anders
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Day-to-day variability in travellers' activity-travel patterns in the Jakarta metropolitan area2016In: Transportation, ISSN 0049-4488, E-ISSN 1572-9435, Vol. 43, no 4, p. 601-621Article in journal (Refereed)
    Abstract [en]

    Using four consecutive days of SITRAMP 2004 data from the Jakarta metropolitan area (JMA), Indonesia, this study examines the interactions between individuals’ activity-travel parameters, given the variability in their daily constraints, resources, land use and road network conditions. While there have been a significant number of studies into day-to-day variability in travel behaviour in developed countries, this issue is rarely examined in developing countries. The results show that some activity-travel parameter interactions are similar to those produced by travellers from developed countries, while others differ. Household and individual characteristics are the most significant variables influencing the interactions between activity-travel parameters. Different groups of travellers exhibit different trade-off mechanisms. Further analyses of the stability of activity-travel patterns across different days are also provided. Daily commuting time and regular work and study commitments heavily shape workers’ and students’ flexibility in arranging their travel time and out-of-home time budget, leading to more stable daily activity-travel patterns than non-workers.

  • 78.
    Dharmowijoyo, Dimas B. E.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Susilo, Yusak O.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Karlström, Anders
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, System Analysis and Economics.
    On complexity and variability of individuals’ day-to-day discretionary activitiesManuscript (preprint) (Other academic)
  • 79.
    Dharmowijoyo, Dimas B. E.
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Susilo, Yusak O.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Karlström, Anders
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, System Analysis and Economics.
    Relationships among discretionary activity duration, travel time spent and activity space indices in the Jakarta Metropolitan Area, IndonesiaManuscript (preprint) (Other academic)
  • 80.
    Dharmowijoyo, Dimas Bayu Endrayana
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    The complexity and variability of individuals' activity-travel patterns in Indonesia2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Considering an individual’s day-to-day variability of activity-travel patterns will provide a more complete description of how an individual behaves to adapt the changing constraints and resources on different days. Without this day-to-day variability understanding, the individual’s behaviour would not be fully grasped and any suggested policy, planning and development would not completely achieve their desired objectives. The day-to-day behaviour is a subject to an interaction between individual’s needs and time-space constraints. The availability of ‘external’ resources (e.g., disposable income, built environment accessibility, and access to different travel mode/s) gives more opportunities for some individuals to participate in certain activities and/or trips than others. The constraints do not only consider budget and time constraints, but also include how an individual associates with other individuals and materials, and complies with any given authorities’ rules and regulations. The needs-constraints interaction also unveils some endogeneities which may not be captured by microeconomic and attitude theories. Failing to understand these interactions will underestimate the individual’s complex decision making process for performing certain behaviour.

    The constraints are not solely about physical constraints and instrumental factors, such as travel mode availability, time and cost. It is also influenced by individual’s non-instrumental variables, such as motivation, volition and habits. Currently there is a lack of knowledge how these non-instrumental variables are interacting and influencing the constraints to shape the individual’s travel behaviour. The implementation of certain activity-travel policy which only focuses in giving more opportunities to an individual within time and space resources without considering an individual’s attitude and/or habit may not be well accepted and followed by member of public. Moreover, the integration also reveals how an individual puts different priority on different potential activities based on the how an individual allocates/does not allocate time in engaging certain activities when having strong commitment and intention. In addition, including an individual’s health condition in the analysis may help in coordinating certain public health related policy with activity-travel policy.

    This thesis includes six papers which investigated the factors described above. The first three papers investigated how activity participation and built environment variables which can represent individuals’ constraints explain the day-to-day variability of individuals’ behaviours. Furthermore, the fourth and fifth paper explored the interaction between individuals’ time-use and activity participation, subjective characteristics and health factors. Lastly, the sixth paper examined how the time-space constraints and health condition explain the degree of variability in individuals’ multi-facet and multi-dimensional activity-travel patterns using sequential alignment method.  

  • 81. Ding, Jing
    et al.
    Gao, Song
    Jenelius, Erik
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Rahmani, Mahmood
    KTH.
    Pereira, Francisco
    Ben-Akiva, Moshe
    Latent-class routing policy choice model with revealed-preference data2015Conference paper (Refereed)
  • 82.
    Duarte, Joakim
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport planning, economics and engineering.
    Potentiella cyklister i Stockholm: Faktorer som påverkar benägenheten att cykla2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Städer som saknar infrastruktur och som har en låg befolkningsdensitet tycks ha en betydligt lägre andel cyklister. När fler personer cyklar blir cykeln ett naturligare inslag i stadstrafiken, vilket bl.a. medför att städer med fler cyklister generellt sett är säkrare att cykla i. Andra städer skiljer sig från Stockholm beträffande befolkningsmängd, existerande infrastruktur för cyklister och hur stor andel av alla resor som sker med cykel. Att jämföra andra städer med Stockholm är ett problem på grund av dessa skillnader. Att förutse en förändring i andelen cyklister utifrån en jämförelse städer emellan blir därför svår.

    En litteraturstudie med målet att identifiera och värdera aspekter som påverkar cyklister och valet att börja cykla genomförs. Betydelsen av infrastruktur undersöks och resultatet visar att infrastrukturen är av stor vikt och att brister i infrastrukturen leder till att få kan tänka sig att börja cykla. Bristande infrastruktur leder till att viktiga förutsättningar saknas. Dessa förutsätt-ningar inkluderar bl.a. trafiksäkerhet och parkeringsmöjligheter. Villigheten att byta färdmedel tycks finnas hos bilister, eftersom de utvärderar sina vägval och andra aspekter av resan när omständigheter förändras. Att använda sig av skiftande omständigheter för att förutsäga antalet nya cyklister i Stockholm är dock problematiskt, på grund av att många av de viktigaste fak-torerna saknas i RVU Sverige.

    Resultatet blir att andelen resor som sker med cykel i Stockholm kommer att öka med en ök-ningstakt som de jämförda städerna tidigare har upplevt. Författaren har gjort en uppskattning av hur många tidigare bilister och kollektivtrafikresenärer som kan antas byta färdmedel, detta har gjorts genom att sålla bort de med sämst förutsättningar att börja cykla. Uppskattning är grundad på förutsättningarna som RVU tillhandahåller, detta medför att uppskattningen är trub-big och relativt missvisande på grund av saknade frågor i RVU Sverige.

  • 83.
    Duvalon Clark, Juan Raul
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Construction and demolition waste transport in Stockholm: A geospatial and comparative analysis between road- and intermodal transport2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 84. Eilers, S.
    et al.
    Mårtensson, Jonas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Pettersson, H.
    Pillado, M.
    Gallegos, D.
    Tobar, M.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Ma, Xiaoliang
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Friedrichs, T.
    Borojeni, S. S.
    Adolfson, M.
    COMPANION-Towards Co-operative Platoon Management of Heavy-Duty Vehicles2015In: IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC, IEEE , 2015, p. 1267-1273Conference paper (Refereed)
    Abstract [en]

    The objective of the EU project COMPANION is to develop co-operative mobility technologies for supervised vehicle platooning, in order to improve fuel efficiency and safety for goods transport. The potential social and environmental benefits inducted by heavy-duty vehicle platoons have been largely proven. However, until now, the creation, coordination, and operation of such platoons have been mostly neglected. In addition, the regulation and standardization of coordinated platooning, together with its acceptance by the end-users and the society need further attention and research. In this paper we give an overview over the project and present the architecture of the off-board and onboard platforms of the COMPANION cooperative platoon management system. Furthermore, the consortium reports on the first results of the human factors for platooning, legislative analysis of platooning aspects, clustering and optimization of platooning plans and prediction of congestion due to planned special events. Finally, we present the method of validation of the system via simulation and trials.

  • 85. Ekstrand, E. E.
    et al.
    Gustafsson, A. G.
    Norhammar, A. N.
    Näsman, Per N.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Ryden, L. R.
    Kjellstrom, B. K.
    Periodontal disease: A potential risk factor for myocardial infarction in younger women2016In: EUROPEAN HEART JOURNAL, ISSN 0195-668X, Vol. 37, p. 350-350Article in journal (Refereed)
  • 86.
    Eliasson, Jonas
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport planning, economics and engineering.
    Introduction to the special issue on appraisal2014In: Research in Transportation Economics, ISSN 0739-8859, E-ISSN 1875-7979, Vol. 47, p. 1-2Article in journal (Other academic)
  • 87.
    Eliasson, Jonas
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Is congestion pricing fair?: Consumer and citizen perspectives on equity effects2016In: Transport Policy, ISSN 0967-070X, E-ISSN 1879-310X, Vol. 52, p. 1-15Article in journal (Refereed)
    Abstract [en]

    This paper discusses and analyses whether congestion charges can be considered to be “fair” in different senses of the word. Two different perspectives are distinguished: the consumer perspective and the citizen perspective. The consumer perspective is the traditional one in equity analyses, and includes changes in travel costs, travel times and so on. Using data from four European cities, I show that high-income groups pay more than low-income groups, but low-income groups pay a larger share of their income. I argue that which of these distributional measures is most appropriate depends on the purpose(s) of the charging system. The citizen perspective is about individuals’ views of social issues such as equity, procedural fairness and environmental issues. I argue that an individual can be viewed as a “winner” from a citizen perspective if a reform (such as congestion pricing) is aligned with her views of what is socially desirable. Using the same data set, I analyse to what extent different income groups “win” or “lose” from a citizen perspective – i.e., to what extent congestion pricing is aligned with the societal preferences of high- and low-income groups. It turns out that these differences are small, but overall, middle-income groups “win” the most in this sense.

  • 88.
    Eliasson, Jonas
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport planning, economics and engineering.
    Opportunities for transport financing through new technologies: State of the art and research needs2014In: Urban Access for the 21st Century: Finance and Governance Models for Transport Infrastructure / [ed] Elliott D. Sclar, Måns Lönnroth, Christian Wolmar, Taylor & Francis, 2014, p. 118-145Chapter in book (Refereed)
  • 89.
    Eliasson, Jonas
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Problemstyrd planering: en förklaring till att effektivitet spelar så liten roll för valet av transportåtgärder.2015In: Ressursbruk i transportsektoren – noen mulige forbedringer. / [ed] Morten Welde, James Odeck, Oslo: Concept , 2015Chapter in book (Refereed)
  • 90.
    Eliasson, Jonas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Börjesson, Maria
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Hamilton, Carl
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Fler bussar i Stockholm bättre än nytt spårvägsnät: DN Debatt2011In: Dagens nyheter, ISSN 1101-2447Article, book review (Other (popular science, discussion, etc.))
  • 91.
    Eliasson, Jonas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Börjesson, Maria
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Hamilton, Carl
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Kristoffersson, Ida
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Flexibel trängselskatt ger flyt åt Stockholmstrafiken: DN Debatt2012In: Dagens nyheter, ISSN 1101-2447Article, book review (Other (popular science, discussion, etc.))
    Abstract [en]

    Omstridd skatt fyller sex. Trängselskattens påverkan på trafiken är till och med större i dag än när den infördes. Att många ändå upplever att köerna blivit längre beror på flera stora byggprojekt som påverkar kapaciteten på vägarna. Trängselskatten bör därför bli mer flexibel och anpassas efter vägarbeten, årstider etc. Essingeleden bör också snarast avgiftsbeläggas. Det skulle enkelt minska trafiken där med 13 procent och göra Stockholm effektivare, renare och trevligare, skriver fyra transportforskare.

  • 92.
    Eliasson, Jonas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport planning, economics and engineering. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Proost, Stefaan
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport planning, economics and engineering. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Is sustainable transport policy sustainable?2015In: Transport Policy, ISSN 0967-070X, E-ISSN 1879-310X, Vol. 37, p. 92-100Article in journal (Refereed)
    Abstract [en]

    This paper discusses a specific part of sustainable transport policy, namely policies to reduce greenhouse gas emissions from the transport sector. We explain how assessments of such policies will overestimate their effectiveness if market responses are not taken into account. The substantial difference between market price and extraction cost of oil means that consumption reductions will be watered down by price responses causing increased consumption in other places (spatial leakage) and in the future (intertemporal leakage). The difference between market price and extraction cost also has negative implications for the viability of alternative technologies. Leakage effects become larger when consumption reductions are only undertaken by a subset of countries: we review some theoretical evidence why strong binding international climate agreements are so difficult to reach and to enforce. All this may require rethinking climate policies for the transport sector: What policies remain cost effective for reducing greenhouse gas emissions?

  • 93.
    Emil, Jansson
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Effekter av att omleda höghastighetståg: En fallstudie på Ostlänken2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To hear of train disruptions on the news has been more a rule than an exception in recent years,

    whether it is signal failure or torn down contact lines, all these disturbances have caused enormous

    problems both for passengers and goods. A big reason that disruptions have such a big impact on the

    railway system is that there are very limited opportunities to divert trains. However, this may change

    with the future high-speed network in Sweden, where the first stage is the Eastern Link, a new

    double track railway between Järna - Linköping for speeds up to 320 km / h. Thus, there will be two

    double-track railways on the route and moreover the single-tracked Nyköping line, which will open

    up entirely new opportunities to reroute high-speed trains from the Eastern Link when future failures

    occur.

    The purpose of this work is to see what effects the rerouting of high-speed train has on other trains

    as well as on the rerouted trains. To see these effects a case study is being carried out on the Eastern

    Link with an unplanned shutdown between Norrköping - Nyköping, where high-speed trains will be

    diverted in four different scenarios. The goal of the study is to find the best alternative route for the

    Eastern Link trains in terms of travel time, impact on the other traffic and the number of stations

    served. Finally, a general model is developed to estimate the total diversion time for high-speed

    trains.

    As the Eastern Link is scheduled to be completed in 15 years, other countries like Italy and France

    that already had a large high-speed network are looked into on the rerouting possibilities they have.

    A common thing for both countries is that they have built many connection points between the

    ordinary and high-speed network which provides great opportunities for the rerouting of high-speed

    trains.

    The case study is being done with the simulation software RailSys where the four study options and

    the comparing alternative are simulated. The simulation takes place in the area of Södertälje -

    Hallsberg - Linköping - Nyköping. In order to get a realistic picture of how the traffic can come to look

    at the opening of The Eastern Link, year 2030, both forecasts and current timetables (T15) are used.

    The use of T15 is being motivated that no travel time reductions will be made on the relevant

    courses and that the Western and Southern main line are already heavily loaded.

    The result indicates that the diversion of high-speed rail has a very marginal impact on other traffic,

    this is explained by the fact they can keep the track speed limit. In an unplanned shutdown between

    Norrköping-Nyköping study option 3 (UA3) is recommended, this option uses both the Southern

    Main Line and the Nyköping line. The developed model shows that there is potential to calculate the

    total diversion time and thus better able to predict arrival times for the rerouted trains.

  • 94.
    Enström, Anna
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Kerrén, Thed
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Cykeln tar plats: En studie om cyklisters omkörningsbeteende och utrymmesbehov i stadsmiljö2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In today’s traffic planning, there is a lack of knowledge concerning how cyclists behave during overtakings and what space this requires. The purpose of this report is to collect information and knowledge about cyclist behavior in different traffic situations, to increase the chance of bicycle infrastructure being designed in a way that best suits the cyclists themselves.

    The main topic of this report is how cyclist speed is distributed in bicycle paths of different standards, and how this can be used to determine the performance of a certain bicycle path. It will also be examined how lack of space affects the number of overtakings. Furthermore, the report will inquire how much space an overtaking demands, as well as if the difference in speed can be related to the width and length of an overtaking.

    The above questions are answered through a literature study where results from existing studies are presented, as well as through a case study where two bicycle paths of different standards and widths are compared. The method for collecting data is video recording, paired with manual video analysis.

    The most important conclusions of this study are that bicycle paths with more limited width have a larger proportion of bound vehicles, and that this proportion increases with the flow in the opposite direction, at least where width is limited. It was not possible to show any relationship between the width of an overtaking and the speed difference between two cyclists. However, overtaking width was found to be greater on wider bicycle paths than on narrower paths. Results also show that cyclists with greater speed tend to place their vehicle further away from the lane edge than slower cyclists do. Furthermore, it was observed that on bicycle paths with good space standard, there was a linear relationship between flow and the overtaking frequency. Finally, a model to compute the length of an overtaking was developed, but unfortunately this model could not be validated due to lack of measuring resources.

  • 95.
    Fadaei, Masoud
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    Cats, Oded
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. Delft University of Technology, Netherlands.
    Evaluating the impacts and benefits of public transport design and operational measures2016In: Transport Policy, ISSN 0967-070X, E-ISSN 1879-310XArticle in journal (Refereed)
    Abstract [en]

    Design and operational measures are designed and implemented to improve public transport performance and level-of-service. In the case of urban bus systems, priority, operational and control measures are aimed to elevate bus services to buses with high level of service (BHLS). Even though there is an explosive growth in design and operational measures implementation and growing research interest in investigating their impact on performance indicators, there is lack of a systematic evaluation of their benefits. We present an evaluation framework and a detail sequence of steps for quantifying the impacts of public transport design and operational measures. The effects of service performance on travel times and costs are assessed by accounting for relations between reliability and waiting times, crowding and perceived travel times, and vehicle scheduling and operational costs. The evaluation integrates the implications of reliability on generalized passenger travel costs and operational costs. We deploy the proposed evaluation framework to a field experiment in Stockholm where a series of measures were implemented on the busiest bus line. The results suggest that the total passenger and operator benefits amount to 36.8 million Swedish crowns on an annual basis. The overall assessment of the impacts of design and operational measures enables the comparison of different implementations, assess their effectiveness, prioritize alternative measures and provide a sound basis for motivating investments.

  • 96.
    Fadaei, Masoud
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Cats, Oded
    Delft University of Technology, Netherland.
    Real-Time Bus Departure Time Predictions: Vehicle Trajectory and Countdown Display Analysis2014In: 2014 IEEE 17th International Conference on Intelligent Transportation Systems (ITSC), IEEE conference proceedings, 2014, p. 2556-2561Conference paper (Refereed)
    Abstract [en]

    Uncertainty is an important challenge in operating bus systems. Accurate real-time predictions can therefore facilitate adaptive decision making process of both operations and passengers. This scheme should be tractable, fast and reliable to be used in real time applications. This paper presents a hybrid prediction scheme to generate real-time information concerning downstream vehicle trajectories and next bus arrival. The prediction generated by the proposed hybrid scheme integrates three travel time components: schedule, instantaneous and historical data. Genetic algorithm is applied in order to specify the contribution of each data source component to the prediction scheme. The benefits, transferability and estimation form of the proposed scheme were tested by applying it on three trunk bus lines in Stockholm, Sweden. Its performance was compared to a commonly deployed scheme. The results indicate that the proposed scheme reduces significantly the overall mean absolute error for all routes from both operators' and passengers' perspectives.

  • 97.
    Fadaei, Masoud
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, System Analysis and Economics.
    Cats, Oded
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. Delft University of Technology, Netherland.
    Bhaskar, Ashish
    Smart Transport Research Centre, School of Civil Engineering and Built Environment, Queensland University of Technology (QUT), Australia.
    A Hybrid Scheme for Real-Time Prediction of Bus TrajectoriesManuscript (preprint) (Other academic)
    Abstract [en]

    The uncertainty associated with public transport services can be partially counteracted by developing real-time models to predict downstream service conditions. In this study, a hybrid approach for predicting bus trajectories by integrating multiple predictors is proposed. The prediction model combines schedule, instantaneous and historical data. The contribution of each predictor as well as values of respective parameters is estimated by minimizing the prediction error using a linear regression based heuristic. The hybrid method was applied to five bus lines in Stockholm, Sweden and Brisbane, Australia. The results indicate that the hybrid method consistently outperforms the timetable and delay conservation prediction method for different line layouts, passenger demands and operation practices. Model validation confirms model transferability and real-time applicability. Generating more accurate predictions can help service users adjust their travel plans and service providers to deploy proactive management and control strategies to mitigate the negative effects of service disturbances.

  • 98.
    Fadaei Oshyani, Masoud
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Cats, Oded
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. Delft University of Technology, The Netherlands.
    Bhaskar, Ashish
    A hybrid scheme for real-time prediction of bus trajectories: Hybrid Scheme for Real-Time Prediction2017In: Journal of Advanced Transportation, ISSN 0197-6729, E-ISSN 2042-3195, Vol. 50, no 8, p. 2130-2149Article in journal (Refereed)
    Abstract [en]

    The uncertainty associated with public transport services can be partially counteracted by developing real-time models to predict downstream service conditions. In this study, a hybrid approach for predicting bus trajectories by integrating multiple predictors is proposed. The prediction model combines schedule, instantaneous and historical data. The contribution of each predictor as well as values of respective parameters is estimated by minimizing the prediction error using a linear regression heuristic.The hybrid method was applied to five bus lines in Stockholm, Sweden and Brisbane, Australia. The results indicate that the hybrid method consistently outperforms the timetable and delay conservation prediction method for different line layouts, passengerdemands and operation practices.Model validation confirms model transferability and real-time applicability. Generating more accurate predictions can helpservice users adjust their travel plans and service providers to deploy proactive management and control strategies to mitigate the negative effects of service disturbances.

  • 99.
    Fares, Mazen
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering.
    Evaluation method of the saturation level of a railway line2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Saturation is becoming more and more of an issue for infrastructure owners, but there is no existing

    method to measure it. This master thesis aims at suggesting a method in order to evaluate the

    saturation level of a railway line. Saturation has an ambiguous definition. It deals with capacity

    issues, timetable stability and robustness, and with delay issues. Three methods are mainly studied,

    each one defining saturation from a different angle, and meeting a different definition of saturation.

    These methods are the compression method, defining saturation as a capacity issue, the robustness

    method, and the regularity method, i.e. delays analysis. A fourth method is created and studied in

    order to complete the previous three. The idea is to find the relevant indicators to evaluate

    saturation. These methods are first studied from a theoretical perspective before being applied to a

    study case to choose the relevant indicators. This study case involves a statistical analysis and a

    dynamic simulation of the graphical timetable. The results show that the regularity method is

    irrelevant to study saturation. The method suggested by this master thesis in order to evaluate

    saturation is a two-step method. The first step is the diagnosis based on the compression method

    and the traffic heterogeneity. The second step is the comparison between different scenarios to

    reduce saturation: this step is based on the compression method, the robustness method and the

    traffic heterogeneity. This method can later be used for an economic study or a multi-criteria

    analysis.

  • 100.
    Fernandez Abenoza, Roberto
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, System Analysis and Economics.
    Cats, Oded
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Transport Planning, Economics and Engineering. Delft University of Technology, Netherlands.
    Susilo, Yusak Octavius
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, System Analysis and Economics.
    Travel satisfaction with public transport: Determinants, user classes, regional disparities and their evolution2017In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 95, p. 64-84Article in journal (Refereed)
    Abstract [en]

    Increasing public transport ridership while providing a service that better caters to individual travelers poses an important goal and challenge for society, particularly public transport authorities and operators. This study identifies and characterizes current and potential users of public transport in Sweden and identifies the most important determinants of travel satisfaction with Public Transport services for each segment of travelers. In addition, it investigates the changes over time of attribute importance among the different segments and the inter-segment geographical variation of overall satisfaction. The analysis is based on a dataset of almost half a million records. Travelers were clustered based on their socio-demographics, travel patterns and accessibility measures to enable the analysis of determinants of satisfaction for different market segments. The cluster analysis results with five segments of Swedish travelers include: (i) inactive travelers; (ii) long distance commuters; (iii) urban motorist commuters; (iv) rural motorist commuters and;(v) students. By contrasting satisfaction with the importance of each quality of service attribute, three key attributes that should be prioritized by stakeholders are identified: customer interface, operation, network and  length  of  trip time. Interestingly, the results suggest an overall similarity in the importance of service attributes among traveler segments. Nevertheless, some noticeable differences could be observed. The quality of service attributes’ importance levels reveal overall changes in appreciations and consumption goals over time. The more frequent public transport user segments are more satisfied across the board and are characterized by a more balanced distribution of attribute importance while rural motorist commuters are markedly dissatisfied with service operation attributes. This work can help authorities to tailor their policies to specific traveler groups.

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