It's not speed per se that is a problem, rather the aim of speed limits is to make sure you can control your car and not cause accidents. If everyone is drivin

It's not speed per se that is a problem, rather the aim of speed limits is to make sure you can control your car and not cause accidents. If everyone is driving the 'recommended' speed of 130kmh on a German motorway then it is a severe risk if you drive slower. Road users need to be predictable. Trucks or motorhomes are slower, but you expect them to be slower. You see them from the distance and plan ahead. But a normal car that drives 60 when all others drive 130-140 is a massive danger as other drivers do not expect it to do so, so will lose precious seconds to react. You can get fined for driving unnecessarily slow. In Germany you also cannot merge onto the motorway unless you have a certain speed already, and you cannot enter the motorway at all if your car can't do an appropriate minimum speed (or you have special transport papers and warning lights).