Miniature drivers and passengers

Try a search for Masterbox.  They do injection molded figures in 1/24 scale, including civvies.

There are TWO different box's full accessories made by Itelari with 24th scale figures in them, look on Ebay for Itelari kit # 720 and kit # 764.   

Here's one of the figures from Itelari kit # 764, truck is 25th scale and the figure just fits in real easy. You can even do some modifications to the figures as well, just to make things a bit more interesting. 

Here ya go.

https://hobbyterra.com/search.php?&manufacturers_id=26&attributes_id=5

Cops, robbers, truckers, sexy ladies, joggers, a guy letting his dog pee.  You could probably find something in there that you could use. I don’t think they have covered 50’s drive-in types yet, but they probably will sooner or later.