Paint shop Boost

This has been a bottle neck for me even with the extra driers it does not seem to make much difference to cars going through quicker.
is there a quick fix to speed it up?
And also there are Robots in there that paint the cars (well there was when i used to work in there)
can we not intoduce Robots in the paintshop to speed things up?

1 axel line => 2 roof fit => 3 paint lines.

This usually solves for me the bottleneck.