Värmdö is a commuter municipality to Stockholm. Road 222 between Värmdö and Stockholm is the main commuter route for both bus and car traffic. Road 222 is a bottleneck at Farstabron in the direction towards Värmdö, where the motorway will go from two to one lane and become a non-meeting motorway. Towards Stockholm, the bridge has two lanes, which is why capacity is not affected as strongly in that direction. The accessibility problems arise mainly in the direction of Värmdö during maximum hours in the afternoon and during weekends and summer time as the municipality also has many holiday homes. Measures to improve accessibility have been raised by both the municipality and the Swedish Transport Administration. Building a new bridge is not relevant as the remaining expected technical life of the bridge is long. The Swedish Transport Administration has an idea for a reversible lane solution on the bridge, which is the proposal studied in this thesis. Data collection and traffic analysis has been performed to study how the travel time effect would be if Farstabron was rebuilt into a reversible 2 + 1 road, with or without a reversible bus lane. The tool used is the microsimulation program PTV VISSIM. The results show that a reversible solution without a bus lane is the alternative that provides by far the largest travel time gains for both car and bus in 2040.

The degree project contains a chapter that deals with traffic engineering theory and traffic simulation theory as well as a literature study chapter that summarizes the knowledge about reversible lanes. The information about reversible lanes, even international studies, is poor.Experiences of reversible lanes is good and is mainly to be recommended as the flow in one direction is significantly greater than in the other. The traffic safety risk is primarily linked to unprotected road users. The most common internationally according to what has been identified is to implement reversible lanes on motorways with protective barriers. However, no reversible lane without a barrier have been identified holding 80km/h. Studies have shown that reversible lanes could have a cost-benefit ratio of around 7, which means that the benefit outweighed the costs 7 times in money measured.

The weaving dynamics of VISSIM from two to one lane were challenging to calibrate against the reality. Preparatory behavior during lane changes is mainly affected by car-following and lane-changing models in VISSIM. In the simulation the correlation with collected data was slightly more accurate with the car following model for W99 (freeway) rather than W74 (weaving urban rd).