The Issue: Civillians have no where to park at DOC.
My Solution: Give them parking lots (or read my suggestion here: https://www.anzus.life/topic/20910-doc-upgrades/ )
D3S have more variety, which makes them more enjoyable due to such a diversity. With the ability to make some cars rare and also having more in general will make it more like real life. While also adding a sense of normality because usually there is a lot of different cars especially in the police force.