The challenge facing urban planners and politicians in many European towns and cities is that of balancing the demand for increasing personal mobility and economic growth, with the need to respect the environment and provide an acceptable quality of life for all citizens. While it is clear that provision for car-based mobility will continue to be an important part of traffic management planning, finding ways to encourage more use of alternative modes of transport (public transport, cycling and walking) is the goal of any sustainable urban policy. Where road space is restricted, providing adequate space for these alternative modes may require a reallocation of highway capacity. When the roads under consideration are already highly congested, it is typically assumed that reducing the capacity available for cars will result in increased traffic congestion in the surrounding streets. However, as the evidence in this document demonstrates, this is not necessarily the case. The experience in a number of European cities is that: u0095 traffic problems following the implementation of a scheme are usually far less serious than predicted; u0095 after an initial period of adjustment, some of the traffic that was previously found in the vicinity of the scheme u0091disappearsu0092 or u0091evaporatesu0092, due to drivers changing their travel behaviour; u0095 as a result the urban environment becomes more liveable in many respects. This handbook illustrates the concept of traffic evaporation using case studies from a selection of European cities. Many of these cities have gone ahead with road space reallocation schemes despite predictions that traffic chaos would result. However, in each case any initial problems of traffic congestion were short-lived, and after a u0091settling-inu0092 period a proportion of the traffic was found to have u0091evaporatedu0092.