You are only allowed to use a footpath on foot, riding a bicycle or horse constitutes as a trespass against the landowner. On a bridleway you can travel on foot, horse back and on a bicycle. On a restricted-byway you are also allowed to travel by horse drawn carriage. On a Byway open to all traffic you are also allowed to travel by motorised vehicle.
Driving a motorised vehicle on a public footpath or bridleway is illegal without legal authority (e.g. the landowner or tenant of the land over which the footpath runs can drive a vehicle over it). Report suspected trespass or offences to the highway authority (county council or unitary authority).