hi there
we have a vehicle section in the employment contract
daily checks, cleanliness, usage, accidents, parking etc.
does it work,

if you police it yes.
you may like to put a clause in about the vehicle coming back to you in the condition it was given to them in the first place, and then cost of repairs if they dont.
vehicles, are always an issue, it can be similar with the kit that they have in the back of them
unfortunately people will never look after something that isnt theirs, as well as you will look after it.
regards
martin