For this type of level, there are several important tips:

1) All intersections should be strictly perpendicular.

2) The gap between roads should be exactly enough to fit one car waiting for its turn to enter the crossroad. No car should be waiting at a random angle, blocking those behind it.

3) All connections must be smooth. Since car speeds won’t be extreme, there’s no need to worry about curvature, but cars should not slow down at the crossroads.

Yeah there's definitely room to improve. I found the largest bump from smoothing out purple to orange route. That and if you fix the triangle intersection between yellow and green, which is hard because it keeps jamming

Oh, come on, Satse :) Suprisingly? I've been using it for eternity https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3459209954

It was already a record-bearing layout when NoblesseHaki improved it further.

Surprisingly mess and efficient layout. i think there is ways to improve this touch a lot. Great work!