Speed in m/s has a safety aspect to it. It takes a typical driver one second to notice danger, remove foot from the gas pedal, place it on the brake pedal and apply a force. At the typical highway speed, the car has traveled 30 m in that one second (several car lengths for those not adverse in m).
Posting speed limits in m/s could make drivers more aware of the safe distance. They might even find it handy: in 1 ks, they would travel 30 km. Stan Jakuba www.metric1.net/sijakub
