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Badia, Hugo
Publications (3 of 3) Show all publications
Zhang, W., Jenelius, E. & Badia, H. (2019). Efficiency of semi-autonomous and fully autonomous bus services in trunk-and-branches networks. Journal of Advanced Transportation, Article ID 7648735.
Open this publication in new window or tab >>Efficiency of semi-autonomous and fully autonomous bus services in trunk-and-branches networks
2019 (English)In: Journal of Advanced Transportation, ISSN 0197-6729, E-ISSN 2042-3195, article id 7648735Article in journal (Refereed) Published
Abstract [en]

Automation technology is expected to change the public transport sector radically in the future. One rising issue is whether to embrace the intermediate stage of semi-autonomous buses or to wait until fully autonomous buses are available. This paper proposes a cost model of bus operations considering automation technology. The generalized cost, which is the sum of waiting, riding, operating, and capital cost, is modeled for conventional, semi-autonomous, and fully autonomous bus services on a generic trunk-and-branches network. Semi-autonomous buses achieve reduced unit operating cost through automated platooning on the corridor. The relative efficiency of the different services is studied under a range of scenarios for commercial speed, network structure, and demand distribution. Analytical and numerical results show that fully autonomous buses exhibit great potential through reduced operating and waiting costs even if the additional capital cost is high. The advantages of semi-autonomous buses are weaker and most prominent in networks with low demand along a long corridor such as interurban networks. For both automation levels a commercial speed comparable to conventional vehicles is crucial. The established criteria provide input to planners and operators for understanding the potential of automated bus services.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2019
National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:kth:diva-237286 (URN)10.1155/2019/7648735 (DOI)000460891200001 ()2-s2.0-85062792951 (Scopus ID)
Note

QC 20181107

Available from: 2018-10-26 Created: 2018-10-26 Last updated: 2019-05-24Bibliographically approved
Leurent, F., Li, S. & Badia, H. (2019). Structural design of a hierarchical urban transit network integrating modal choice and environmental impacts. In: 21st EURO Working Group on Transportation Meeting, EWGT 2018, 17th – 19th September 2018, Braunschweig, Germany: . Paper presented at 21st EURO Working Group on Transportation Meeting, EWGT 2018, 17 September 2018 through 19 September 2018 (pp. 99-106). Elsevier, 37
Open this publication in new window or tab >>Structural design of a hierarchical urban transit network integrating modal choice and environmental impacts
2019 (English)In: 21st EURO Working Group on Transportation Meeting, EWGT 2018, 17th – 19th September 2018, Braunschweig, Germany, Elsevier, 2019, Vol. 37, p. 99-106Conference paper, Published paper (Refereed)
Abstract [en]

The paper develops a structural model and a design methodology for transit system planning in an urban area. Transit "components" are modelled by subarea and by sub-mode in terms of line length, station spacing, and fleet size, in order to determine both quality of service and production costs. Roadway networks are modeled with a Macroscopic Fundamental Diagram that relates speed to network capacity and vehicle demand. Local and global environmental impacts are considered. Travel demand includes both mode-dependent users and mode-choosers able to adopt the mode that offers higher utility. The design methodology involves a mathematical program of welfare optimization with respect to transit factors and fares. Two definitions of welfare are given, one that takes into account only demand surplus and supply profit, the other including environmental impacts. An example of application to Greater Paris shows that there is room for system optimization under current subsidy conditions, and that the explicit inclusion of environmental impacts brings about a significant shift in the "optimal" policy package.

Place, publisher, year, edition, pages
Elsevier, 2019
Series
Transportation Research Procedia, ISSN 2352-1457 ; 37
Keywords
design model, environmental impacts, multimodal transportation, social welfare, transit network
National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:kth:diva-251915 (URN)10.1016/j.trpro.2018.12.171 (DOI)2-s2.0-85062239886 (Scopus ID)
Conference
21st EURO Working Group on Transportation Meeting, EWGT 2018, 17 September 2018 through 19 September 2018
Note

QC 20190523

Available from: 2019-05-23 Created: 2019-05-23 Last updated: 2019-05-23Bibliographically approved
Zhang, W., Jenelius, E. & Badia, H.Efficiency of connected semi-autonomous platooning bus services in high-demand transit corridors.
Open this publication in new window or tab >>Efficiency of connected semi-autonomous platooning bus services in high-demand transit corridors
(English)Manuscript (preprint) (Other academic)
Abstract [en]

The paper investigates the efficiency of serving high demand transit corridors with connected semi-autonomous busplatoons in both bus and BRT services. Platooning could make it possible to provide higher capacity than with conventionalbuses by forming virtual long buses out of multiple smaller vehicles, which could be particularly relevant inscenarios with large variation in demand between peak and off-peak hours. The problem is formulated as a constrainedoptimization problem to minimize total system cost, which includes waiting cost, access cost, riding cost, operatingcost and capital cost. For single period with fixed demand, both analytical solutions and numerical examples areprovided. Sensitivity analysis is carried out with regard to demand levels and capacity upper bound. The problemis generalized to a two-period problem considering peak and off-peak demand. Numerical results are provided withsensitivity analysis regarding average demand level and ratio of peak/off-peak demand. Furthermore, the impact of alower bound on service headway is investigated. The result shows that semi-autonomous vehicle platooning is competitivein medium and high demand scenarios, with the potential of reduced users’ cost and operator’s operating costat the expense of additional rolling stock cost. The minimum headway, restricted vehicle size, and higher demandratio all make semi-autonomous platooning more advantageous.

National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:kth:diva-251621 (URN)
Funder
TrenOp, Transport Research Environment with Novel Perspectives
Note

QC 20190520

Available from: 2019-05-16 Created: 2019-05-16 Last updated: 2019-05-20Bibliographically approved
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