Effects of 20mph zones on cycling and walking behaviours in London. Stage 1 – Literature Review

  • Published: 2013
  • Authors: Cedaño-Tovar & I Kilbane Dawe
  • Date Added: 27 Aug 2016
  • Last Update: 27 Aug 2016
  • Format: pdf


Reviews the findings of previous studies on the effect of 20 mph zones.


Literature review

Key Findings:

  • 20 mph zones positively affect safety and perceived safety, two of the key determining factors for modal shift to cycling and walking.

  • Crash occurrences involving cyclists and pedestrians are reduced with lower vehicle speeds and this encourages more people to take up these modes of travel.

  • Both ‘signage only’ and mandatory 20 mph zones with physical traffic calming measures encourage modal shift to cycling and walking. However, physical traffic calming measures should be selected based on the specific needs of the area in which they are to be used.

  • Traffic calming and speed reductions on residential streets are important to enable people to start their cycle trips as most people begin these trips at home.

  • There is a trend in Europe towards prioritising the needs of pedestrians and cyclists over the needs of car drivers in areas of ‘shared space’.

  • Cities in the Netherlands, Denmark and Germany have implemented traffic calming measures and 20 mph speed limits in residential area and in some areas restricted traffic routes.

  • From these countries, the evidence suggests that slow speed zones are a key aspect of increasing cycling. In the Netherlands 27 per cent of all trips are by bike, 18 per cent in Denmark and 10 per cent in Germany.

  • Evidence from Portsmouth , Barcelona and Brussels suggests that 20 mph zones increase road safety and perceptions of road safety, resulting in higher levels of walking and cycling.

  • The introduction of 20 mph zones in London between 1986 and 2006 was associated with a reduction in the number of road casualties by 42 per cent. Reductions amongst cyclists were reduced by 17 per cent.

  • In the Netherland, Denmark and Germany measures such as road narrowing, raised junctions and pavements, traffic circles and extra curves have meant that walking and cycling speeds have increased relative to that of driving, whilst also increasing safety.


Traffic calming, 20 mph zones, safety, cycling


A review of evidence from different cities and countries about the impacts of traffic calming and 20 mph zones on cycling.