Determining Safe Speeds

13 May 2025

The Road Safety Foundation publishes a new report ‘ Determining Safe Speeds ’ following depth collision investigation research from Loughborough University, TRL, Autoliv and Lösningar. 

This report highlights the critical role of speed management in creating a Safe System in which road deaths and serious injuries have been eliminated. Grounded in the principles of Vision Zero, which asserts that no loss of life (or life-changing injury) is an acceptable consequence of mobility, this study provides evidence-based definitions of ‘safe’ speeds for various road types.

Based on the latest publicly available research, the evidence-based maximum operating speeds on British roads if most deaths and life-changing injuries are to be avoided are as follows:

• 10mph where there is a particular prevalence of pedestrians and/or bicyclists and/or motorcyclists, or where there is a heightened vulnerability of pedestrians to impact and injury (e.g. around schools, around hospitals, and in the vicinity of major sports or social/cultural events)

• 20mph in other locations where pedestrians and/or bicyclists and/or motorcyclists mix with cars

• 20mph where cars and HGVs mix and where: o head-on collisions are possible (i.e. single carriageways) or o side impacts are possible (e.g. at T-junctions and crossroads)

• 30mph where head-on collisions and side impacts are possible only between cars