Minimum speeds on the highways
Unless specifically enforced, the usual speed of cars on highways is anywhere between 140 and 150 km/h. Cars as well as highways are typically well suited for this speed.
Trucks and buses however are not. Their top speed is somewhere in the vicinity of 90 km/h.
The problem is the very large speed discrepancy between the groups which humanly results in mutual frustrations, misjudgments and accidents. Besides this the frequent speed change of cars enforces wear and tear and causes environmental issues.
The solution is the introduction of minimum speeds on the highway. 90 km/h on the right lane, 100km/h in the middle lane (where available) and 130 km/u on the left lane where the maximum speed is 150 km/h. Vehicles that are not able to reach 90 km/h (uphill!) have no place on the highway. This includes special vehicles.
Trucks and buses will have to be allowed to overtake each other every 15 kilometers on the right and middle lane of a short (2km) 3 lane road section. Already today, many of these sections are available. When this is not the case, hard shoulders could be used when they'd monitored electronically. In many countries this system is already in place.
Overtaking with a speed difference of 5 km/h will gain you 3 minutes over a stretch of 100 kilometers and a lot less fuel economy. On the other hand there is human nature, so the overtaking stretches will be necessary.
The result will be that
-trucks will make sure that they are always able to reach 90 km/h and thus not overload.
-older trucks will be sooner replaced by stronger, cleaner modern trucks that incorporate active cruise control.
-The amount of accidents will go down although even today the highway is one of the safest road types around.
When all drivers are promised 50 euro's for each recorded breach of this rule, no enforcing supervision by the police will ever be needed. A simple picture will suffice. (see chapter "onboard camera's".