Parliament will discuss this week if there should be a national map of the locations of all the speed cameras.
Most cantons prefer to keep their location secret, but Solothurn, Lucerne and Sankt Gallen are the exceptions. Each has a map available.
Backers of the plan say simply having a map will increase the deterrent effect. They point to the experience in Sankt Gallen which has 15% fewer accidents.
But others say drivers will use the information to slow down where the cameras are – and speed elsewhere.
The location of mobile cameras will always be a surprise.