To me, you're not qualifying your definition well enough. For how long does it have to be non-functioning in order to cease being classified as a vehicle? For

To me, you're not qualifying your definition well enough. For how long does it have to be non-functioning in order to cease being classified as a vehicle? For example, a car that is temporarily in an auto shop for repairs? If your intent is to say that it's no longer classified as a vehicle until it is once again functional, then I think you'll find that your definition deviates pretty significantly from a conventional dictionary definition (a device intended for transport). That's a relatively large desync which will only hinder consistent communications with the vast majority of English speakers.