There are basically two types of mobility scooters. You cannot use the class 2 mobility scooters on roads as they have a maximum speed of 4mph. These types of the scooter also need no registration. At the same time, you can use the Class 3 mobility scooter on roads. These scooters have a maximum speed of about 4mph off the road and about eight mph on the road. However, the rider must be 14 years or above to drive a class 3 invalid carriage in this case.