Speed management : A road safety manual for decision-makers and practitioners

Source: http://www.who.int/roadsafety/projects/manuals/speed_manual/en/
Manual: http://whqlibdoc.who.int/publications/2008/9782940395040_eng.pdf

Prepared by GRSP, WHO, the FIA Foundation and the World Bank, a good practise manual on speed management.

Speed has been identified as a key risk factor in road traffic injuries, influencing both the risk of a road traffic crash as well as the severity of the injuries that result from crashes.

source: OECD/ECMT Transport Research Centre:
Speed Management report, Paris 2006

For instance, pedestrians have a 90% chance of survival if hit by a car travelling at a speed of 30km/h (19mph) or below, but less than a 50% chance of surviving an impact of 45km/h (28mph) or above.

The risk of a crash and the likelihood of serious injury as a result of a crash both increase with higher vehicle speeds.
• Reducing speed limits lowers the rate of crashes, serious injuries and fatalities.
• Most unprotected road users survive if hit by a car travelling up to 30 km/h.
• Most unprotected road users are killed if hit by a car travelling 50 km/h.
• Speeding is a major road safety problem in many countries, contributing to at least one-third of all crashes, and is an aggravating factor in almost all crashes.

• Speed limits of 30km/h (20mph) should be considered for road lengths where there are high pedestrian movements along and across the road, and no adequate pedestrian segregation.
• The Power model estimates the percentage change in risk as a result of a percentage change in average speed (the relative speed change). For example, a 5% increase in average speed leads to approximately a 10% increase of all injury accidents, and a 20% increase in fatal accidents.
• The aim of a safe road system is to achieve a road transportation system that allows for human error without it leading to death or serious injury.