Although there are many vehicles you can purchase in The Simpsons: Tapped Out, all of them are strictly for show. Vehicles cannot be placed on roads or even over parking lots. Oddly enough all of the vehicles in the game are premium items, which would lead you to believe they do more than just sit there. The only character who even interacts with a vehicle is Respectable Moe with the Limo. So unless you want to setup your town so it looks like the antiques road show has just rolled into town, save your donuts for more interactive items. The only thing these items offer is a bonus multiplier, as do a majority of premium items.