Credible speed limits
Obeying the speed limit results in road safety improvement. If speed limits were more credible, i.e. they fit the road image and the surroundings better, road users would find it easier to obey the speed limit.
In practice, however, speed limits are not always credible. Sometimes motorists want to drive faster than permitted, but they may also think that the set limit is too high. The credibility and acceptance of the speed limit is not only determined by features of road and environment, but also by personal characteristics.
In spite of this, motorists generally use the same features (buildings, vegetation, road width) when judging the speed limit. This offers possibilities for adapting the road features to the safe limit, thus creating a better acceptance of, and obedience to, the speed limit.
For more details:
Fact sheet Towards credible speed limits (pdf)