Speed and speed management

Updated

If the average speed on a road increases, crash risk also increases, as does the risk of a serious outcome. This is true in general terms, but more so when motorised vehicles crash with unprotected road users, such as pedestrians, cyclists and (light) moped riders. Furthermore, speed differences between vehicles at any one time or place are related to a higher crash risk. Drivers that maintain a speed that is higher than the average speed on that road run a higher crash risk; drivers that maintain a speed that is lower than average do not. Drivers often exceed speed limits, for example because they are in hurry, or they enjoy speeding, or go with the flow, or because they do not notice their speed. In general, we assume that almost one third of fatal crashes involves speeding or driving at a speed that is not appropriate to the circumstances.

Speed management consists of several steps, of which determining a safe limit is the first step. Which limit is safe, depends on the road function, traffic mix, and road layout. Always and everywhere, the limit should be credible (logical) and apparent. It can be supported by physical speed reduction measures, such as speed humps, and by traffic enforcement. Physical speed reduction measures greatly affect speed at location level. Intelligent Speed Assistance (ISA) greatly affects driving speed and therefore road safety, an intervening ISA system (which prevents the vehicle from exceeding the speed limit) being more effective than an advisory ISA system. On the main road network, Variable Message signs or Dynamic Lane Control Signs with dynamic speed limits contribute to more homogeneous speeds, fewer abrupt braking manoeuvres, and fewer crashes or near miss crashes. The effects of less stringent measures, such as educational measures or rehabilitation courses, publicity campaigns, community projects and nudging are often minor and short-term.

Why are high speeds dangerous?
How often do people drive too fast?
Why do people drive too fast?
How great is the effect of speed on road safety?
How do speed differences affect road safety?
Does driving speed affect alertness?
How many crashes are caused by (too) high speeds?
Is speeding equally dangerous everywhere?
Is speeding equally unsafe for all road users?
What are the speed limits in the Netherlands?
Is there a minimum speed as well?
How to recognise the prevailing speed limit?
How are speed limits determined?
What are safe speeds?
What are credible speed limits?
What steps does speed management consist of?
Did the increase of the maximum speed to 130 km/h result in more crashes?
Did the reduction of the daytime maximum speed to 100 km/h result in fewer crashes?
How much safer will driving in the urban area be when 30 km/h is the standard speed limit?
How effective are speed cameras and average speed checks?
How effective is intelligent speed assistance (ISA)?
How effective are speed limiters for repeat offenders?
How effective are other speeding measures?
Publications and sources
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