ABSTRACT
Volvo Chair Professor Emeritus, Transportation Research & Injury Prevention Programme,
Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India
The speed at which motor vehicles move in traffic is at the base of the road injury problem. Speed influences both the probability of the occurrence of a crash and the crash consequences in terms of the severity of injuries and the extent of property damage. There is overwhelming evidence that increase in speeds is always accompanied by an increase in the number of crashes and in the average severity of road traffic injuries. Fatalities tend to change disproportionally with change of average speed in a double quadratic way. For example, an average speed reduction by a factor .95 gives an expected reduction of fatalities by a factor (0.952)2=0.815 or 5% reduction of average speed gives 18.5% reduction in expected fatalities. Speed control and traffic calming appear to be the most effective and promising ways to reduce injuries and deaths in road traffic crashes.
