Traffic evaporation

There are very few who would object to less traffic on their local roads. Yet measures to restrict motor vehicle access sometimes lead to local concern and opposition. Many assume traffic to be like water: that it has to flow somewhere, and that if restricted in one place then it will only move to other roads.

The evidence, however, paints another picture.

The most comprehensive study of the phenomenon of “evaporating” traffic was carried out by Sally Cairns, Carmen Hass-Klau, and Phil Goodwin. They examined over 70 case studies of road space reallocation from eleven countries, and collated the opinions from over 200 transport professionals worldwide. The findings suggest that predictions of traffic problems are often unnecessarily alarmist, and that, given appropriate local circumstances, significant reductions in overall traffic levels can occur. In over half the cases, there was an 11% reduction in overall traffic in the area, including main roads. They found that by changing the attractiveness of different travel options, a far wider range of behavioural responses was experienced than has traditionally been assumed.

This phenomenon has been observed recently in London's Waltham Forest. By implementing a Low Traffic Neighbourhood, some streets saw reductions in traffic of as much as 90%, with an overall average of 56% reduction. On the surrounding roads there have been increases, but they have not taken all the displaced traffic. Many journeys that were previously undertaken by car have been replaced with other means. Just one year after the implementation, residents were walking 32 minutes and cycling on average 9 minutes more per week.

When looking at the statistics it is easy to see how this can be achieved: across London, 22% of car journeys are less than 2km.

We believe that the same could be achieved throughout Westminster. Cycling and walking is not only an unattractive option on the majority of the city's roads, but is simply not possible for the vast majority of people as they consider the roads too dangerous. We want to see streets become attractive places to travel actively in - the benefits for all are enormous.