There is an interesting article here on the Olive Press site. About 90 km/h speed cameras on motorways in Spain not allowing for the fact that you can go faster if you are overtaking.

Here is a quote from the article:

"An Automovilistas Europeos Asociados (AEA) statement said cameras on motorways were fining ‘anyone’ travelling above the speed limit without acknowledging a driver overtaking is permitted to speed up to 109km/h in this situation."