Summary

Physical restrictions limit car use in urban areas or other specific zones by reductions in road capacity such as street closures or reallocation of road capacity from cars to other traffic such as buses, cyclists and pedestrians. They include bus priorities, cycle lanes, extensive pedestrian areas, street-running rail such as tram or light rail systems and also traffic calming measures.

Physical restrictions on car use aim to reduce the volume of vehicles to achieve a more balanced allocation of road space. These measures can also improve the attractiveness of public transport, provide better facilities for cyclists and pedestrians, and improve environmental quality and safety.

However, demand impacts will vary according to the capacity of a network at the site where a physical restriction is implemented. If capacity is reduced on a few roads or areas but there is still capacity available on other routes, drivers may divert onto an alternative route which still has available capacity. This will reduce traffic congestion on a specific road, but not lead to an overall reduction in the level of car traffic in an urban area.