You would have to “dispose” the
car if you no longer use it for business purposes, because if you don’t you may
end up taking CCA on the car even though you no longer use it. That could cause
problems with the CRA if they find out. The proceeds of disposition would be the
amount that you got when you got rid of the car (if any). So if you sold it for
scrap, or got a trade in amount when you bought the new car, that would be the proceeds
of disposition.
If the new car is in the same
class as the old car, then you won’t get a terminal loss. You can’t get a gain
unless you sold the car for more than it was worth, which is unlikely if the
car was in an accident.