How are unsold vehicles handled at the end of the business year? Are they returned to the factory for scrap? Sold to rental car agencies at a fleet discount? Sold to public using cash back incentives?
We haven’t designed all of the business side yet, but that is a great question for us to think about, thanks! 
may i suggest that it could be a choice made by the player what to do with said unsold cars, maybe a choice between what geozero wrote ?
That’d be ideal yeah, depends how the rest of that side of things works though
Also, will unsold vehicles affect consumer confidence and affect future sales? Too much left over inventory might actually discourage future buyers. Not enough will mean faster sales… the effects of supply and demand.