Speed is at the core of the road safety problem. There is a strong relationship between speed and both the number of crashes and the severity of the consequences of a crash. If the number of speeding violations on European roads could be reduced, many lives would be saved (for more information, see the ERSO text on speeding).
There is no single solution to the problem of excess and inappropriate speeds. A package of countermeasures is necessary, increasing the effectiveness of each individual measure. Police enforcement is one of the countermeasures. The most appropriate combination of measures is determined by the circumstances. Wegman & Aarts propose an integrated, systematic and stepwise approach to speed management:
Step 1: Setting speed limits
A speed limit needs to reflect the safe speed on that particular road, related to road function, traffic composition, and road design characteristics. Furthermore, a speed limit needs to be credible, i.e. it must be logical in the light of the characteristics of the road and the road environment.
Step 2: Information about the speed limit
The driver must know the actual speed limit, always and everywhere. This can be done by either by the use of consistent roadside signing and road markings, or by the use of in-vehicle systems that inform drivers about the speed limit in force.
Step 3: Road engineering measures
At particular locations low speeds are crucial for safety. Examples are near schools or homes for the elderly, at pedestrian crossings, at intersections. At these locations, physical speed reducing measures such as speed humps, road narrowings and roundabouts can help to ensure cars maintaining a safe speed.
Step 4: Police enforcement to control the intentional speeder
If steps 1 to 3 have been applied, unintentional speed violations will have become an exception. Drivers who then still exceed the speed limit, do so intentionally. Police enforcement will remain necessary to control and punish that group of drivers.
Each of the steps 1 to 4 has to be accompanied by information to drivers on the problem of speed and speeding, what the speed limit system is based on and why, what additional measures have been taken and why, and on the (positive) outcomes of these measures.