Calculating the increase in fatality risk when exceeding the speed limit. The Ministry of Infrastructure and the Environment (IenM) in the Netherlands has developed a toolkit to support the provinces, municipalities, water boards and regional community organisations in their communication about driving speed on the underlying road network which decentralized authorities are responsible for: - 30 km/hour residential area; - urban 50 km/hour road; - 60 km/hour residential area; - rural 80 km/hour road. One of the purposes of this communication toolkit is to make the users understand that the most common exceeding of the speed limit by drivers (up to 20 km/hour above the limit) increases the fatality risk for vulnerable road users considerably. This can be illustrated by the fatality rate in the event of a collision between a pedestrian and a car at different driving speeds and excess speeds. IenM has asked SWOV to supply the required data. This report presents the tables and graphs for the fatality rate of pedestrians in a collision with a car at different travel speeds. Furthermore, it contains the tables and graphs for the braking distance for different driving speeds, in dry and in wet weather conditions. On 30, 50 and 60 km/hour roads the pedestrian’s fatality rate roughly doubles when the car exceeds the limit by 10 km/hour. On a 50 km/hour road, for example, about 1 in 10 pedestrians dies at an impact velocity of 50 km/hour. At 60 km/hour (10 km/hour above the limit) 2 in 10 pedestrians sustain fatal injury and a crash at 70 km/hour (20 km/hour above the limit) is fatal for more than 3 in 10 pedestrians. The braking distance also increases at higher speeds. For example, an emergency manoeuvre on the dry surface of a 50 km/hour road, increases the braking distance by about 30% at 10 km/hour above the limit. This is an extra distance of 8 m. If, also in dry conditions, the driving speed is 70 km/hour (20 km/hour above the limit), the extra braking distance at an emergency stop is 17 m, or approximately 65% longer than at the speed limit of 50 km/hour. On a wet road surface the braking distance at an emergency stop is considerably longer than in dry conditions. This applies to both the stopping distance at the speed limit in force and for the extra braking distance that is required when the limit is exceeded. The tables in Chapter 3 contain the information for all speeds according to the speed limit and for the excess speeds that were investigated.
Samenvatting