Does high speed increase the probability of an accident?

A)Yes.Correct
B)No.
C)It depends on the road; this is not the case on motorways and dual carriageways.
The greater the speed, the greater the risk of accident because the response capabilities of the driver/vehicle combination are reduced and demands increase.
With speed, just as with alcohol, the tunnel effect occurs, which is when peripheral vision is lost and only the centre of the road is seen sharply.