Evaporating traffic? Impact of low traffic neighbourhoods on main roads. Thanks to @LDN_LS /1 https://londonlivingstreets.com/2019/07/11/evaporating-traffic-impact-of-low-traffic-neighbourhoods-on-main-roads/

The most comprehensive study of the phenomenon of disappearing or evaporating traffic was carried out by Sally Cairns, Carmen Hass-Klau and Phil Goodwin in 1998 and followed up in 2002 /2

This brought together experience from 17 case studies of roadspace reallocation from general traffic across 11 countries, with opinions from 200 transport professionals. /3

It shows that traffic does not behave like water moving through pipes, finding an easier path as another narrows. Instead it is a force of human choice, driven by people making all sorts of different decisions when driving conditions change. /4

The respondents in the Cairns study, for example, changed their mode of travel, chose alternative destinations, or the frequency of their journey, consolidated trips, took up car sharing or didn't make the journey at all. /5

In half the case studies, there was an 11% reduction in number of vehicles across the whole area where road space for traffic was reduced, including the main roads. /6

This research shows that low traffic neighbourhoods do not simply shift traffic from one place to another, but lead to an overall reduction in the number of motor vehicles on roads. /7