What is abnormally reduced speed?

We can say that a vehicle is driving at an abnormally reduced speed when it is driving, on any type of road, at a speed lower than the established minimum speed. In the case of motorways and dual carriageways, this is true for vehicles driving at a speed less than 60 km/h, while on all other roads, it is true for vehicles driving at a speed that is less than half the typical maximum speed for that road for each type of vehicle.