If you are the only driver or passenger then that is allowed.
I do not smoke, so it's not a problem.
( Pedantichrist twitter.com/LordManley, Fri 7 Sep 2007, 14:42, archived)

if you are a passenger then
you are not the only person in the vehicle
( Aphex The Mink glasjay.blogspot.com, Fri 7 Sep 2007, 14:44, archived)

Indeed,
but if you are the only driver or passeneger then you are the driver.

Essentially, if a vehicle is allocated to an individual and that individual always drives it alone then all is well.

If he ever gives another worker a lift, even a smoker who also has a van (perhaps broken down because he got some water in the fuel tank, who knows?) then the van becomes non-smoking.
( Pedantichrist twitter.com/LordManley, Fri 7 Sep 2007, 14:46, archived)

what if you're in a cable car
then you could be a passenger and the only person in the vehicle
( Dr. Strange Apparantly those were the droids I was looking for, Fri 7 Sep 2007, 14:50, archived)

or on the DLR?

( gfreeman http://twiglet.myminicity.com/, Fri 7 Sep 2007, 14:51, archived)