Idk if someone has suggested this or not, but it would be good to have tow trucks.
I was thinking that road accident missions require firetrucks and cruisers, and even ambulances, but in real life it is common on big incidents to have at least one tow truck. Garages, they could act as the bases for the tow trucks and could be dispatched from there. You could also add a mission that could be street sweeping which could require tow trucks and police cars and vehicles could be taken to either impound lots or the tow truck garages.