The confusion stems from the laws governing road-legal mobility scooters, known as Class 3 invalid carriages. In the UK, it is estimated that there are at least 100,000 Class 3 mobility scooter users registered with the DVLA. '," says Daniel Swain, a mobility expert at walking aids provider, Seacroft Mobility. "Firstly, every road-going Class 3 scooter must be registered with the DVLA using a V55 form, or you're essentially driving an illegal vehicle. If any of these essential features are broken, you should treat the scooter as a Class 2 (pavement-only) model until the repair is complete.