Simulations make Copenhagen world’s best bicycle city

Hardly any other city in the world encourages bicycle traffic like Copenhagen. The city uses microsimulations by PTV Vissim software to assess which measures will help it to turn this vision into reality.

More than half of the Danish capital’s 650,000 residents bike on a daily basis, even beyond city boundaries. “And it’s set to increase even further,” says Emil Tin of Copenhagen’s Centre for Traffic. Therefore, the city embarked on an expansion of its bicycle network, adding 359 km of cycle tracks, 24 km of cycle lanes, and 32.5 km of cycle “expressways”.

Copenhagen has already been using PTV Vissim software to simulate motorized traffic. With help from consulting group COWI, in 2012 the city added bicycle traffic into its PTV Vissim models, creating an all-in-one tool.

COLLECTING AND VALIDATING DATA

The challenge for COWI was to represent in a micro-simulation the behavior of cyclists at peak hours. Søren Frost, Traffic Modelling and Simulation Expert at COWI, explains: “There were two key aspects for the success of the project: Collecting, processing and checking data; and then translating the results into valid parameters in order to simulate bicycle traffic in PTV Vissim.”

In addition to basic parameters (vehicle characteristics, speed distributions, acceleration behavior), COWI investigated parameters for cycle paths: Following and overtaking actions, and behavior of bikers in narrow street sections and at bus stops. The consultants considered behavior in waiting zones, at stop lines and right-turning actions in connection with node points. GPS measurements contributed to calibration of speed and acceleration behaviors.

REALISTIC SIMULATION

The data from the PTV Vissim simulations forms the basis for future studies of Copenhagen’s bicycle traffic. “This includes questions such as: should cyclists and cars stop at the same stop lines? Are bike boxes the better alternative?”, says Frost.

Further analyses relate to mixed traffic. PTV Vissim simulates how vehicles with different widths interact with each other on a single lane: Motorists and cyclists who share a road, travel in lanes next to each other, or overtake within one lane. “It is possible to specify in which streets cyclists and motorists can share the road, and where a separate bicycle lane is a good idea,” explains Frost.

Tin adds: “Thanks to the model, we can realistically simulate current and future bicycle traffic. Even right-turning on a red light can be represented and the effects on other traffic evaluated.”