Evaluation of Dynamic Bus Lanes in Zurich

In intra-urban environments, buses flowing in mixed traffic with cars are often subject to delays caused by congestion. To avoid unreliable bus services, dedicated bus lanes have been established in many cities, including Zurich. By separating buses from general traffic, they help minimize public transport delays, but at the same time capacity is taken away from car traffic. Recent research proposed the concept of dynamic bus lanes to better exploit urban roads: A lane is dedicated to buses only at the very moment when they run. In the time segment between two buses, all lanes are accessible to cars. The master thesis at hand prepares the implementation of dynamic bus lanes in the city of Zurich by investigating the interactions of buses and cars. By means of videotaping, data was collected at Winzerhalde, where a dedicated bus lane is made accessible to general traffic. Lane occupation, delays, flows, and capacities were calculated in relation to bus presence and compared at up and downstream locations. We found that the bus exerts practically no influence on general traffic when it is led in its own dedicated lane. In contrast, cars are affected in terms of delays and capacities when they flow in mixed fashion with buses. The smoothing effect of the separated bus lane falls away, so capacity is not doubled by making it accessible to cars. However, even when driving behind a bus, the car-carrying capacity of two lanes in mixed road use is higher than that of one lane next to a dedicated bus lane. Given that the share of time during which a bus is present is rather small, depending on the bus frequency, dynamic bus lanes are preferable to dedicated bus lanes from a car’s point of view.