Mots clé traffic safety; standards and regulations; urban planning; transport infrastructure

Speed is the single most important determinant of road safety, affecting the risk of a crash occurring and its severity once it occurs. For example, the chances of surviving crashes for a pedestrian are 90% at 30 km/h or below, but less than 50% at 45 km/h or above. The probability of a pedestrian being killed rises by 8 times as the speed of the car increases from 30 to 50 km/h. For the occupants of a car, an increase in speed from 32 to 80 km/h raises the risk of dying in a crash by 20 times.

Excessive and inappropriate speed is estimated to be the underlying cause of about 30% of the fatal and serious crashes in the European Union (15), where a reduction of the average speed by 3 km/h is estimated to save 5,000-6,000 lives each year and to avoid 120,000 – 140,000 crashes, with a parallel saving of €20 billion in crash costs alone.

Despite the importance of speed as a risk factor, no consensus has been achieved on the harmonization of speed limits at the international level, and countries differ substantially in the speed limits on different types of roads. Other risk factors include: unsafe conditions for vulnerable road users, unsafe road infrastructures, failure to use safety devices (crash helmets, seat belts and child restraints), alcohol and drug abuse.