We often drive without knowing the speed limit of the particular stretch of road we are on.
Along the same stretch of road, the speed limit can change without one realising it, or we may turn onto another road with a different speed limit.
I suggest that the speed limit be painted on the road.
This serves three purposes: It tells the driver that he is going in the right direction, keeps his eyes on the road and indicates the speed limit of the road.
The authorities should also conduct a study and recalibrate the speed limits of some roads which may be able to handle vehicles with higher speed limits.