Note that these vehicle number limits include not only cars and trucks, but also public transport (trams, trains, airplanes, metro, ferries, …), service vehicles, blimps, and so on. Make sure you have a fast CPU and a powerful graphics adapter!
With More Vehicles, up to 65,535 moving vehicles and up to 65,535 parked vehicles are possible. The vanilla game allows at most 16,383 moving vehicles and at most 32,767 parked vehicles. Authors description: This mod increases the limit of spawned vehicles.