Traffic calming – four schemes on distributor roads

  • Published: TRL, 1995b
  • Authors: D.C. Webster
  • Date Added: 05 Feb 2013
  • Last Update: 25 Oct 2016
  • Format: html


To obtain information on suitable traffic calming measures for urban distributor roads.


200 radar readings or automatic equipment was used to record before and after speeds on four distributor road calming schemes.

Key Findings:

  • In four schemes on urban distributor roads, the 85th percentile speeds were reduced to levels below or near the 30 mph limit.

  • On average speeds were reduced by 11 mph from 38 mph to 27 mph. Mean speeds reduced by 10 mph from 34 mph to 24 mph. Across the schemes an overall RTI reduction of 32 per cent (26 – 17.8) was seen.

  • The researchers noted that based on the size of the data set, the change is not statistically significant but is consistent with other research which showed reductions in speed being directly related to reductions in RTIs.


Traffic calming, Distributor roads.