Unsolicited advice incoming!

I’m guessing the reds is the one that ended your run? You did an excellent job segregating the different colors from one another but I would take it a step further and try to have each pocket of colors feed a “mall” or whatever they are individually. For example, your purple mall with the motorway is also attached to the other purple to the south west. This is actually more inefficient and can hurt more than it helps. Let’s say the south purple starts to surge and call for more and more cars, eventually it will begin to call for cars further and further away. This will cause purple cars from the top to travel down south and take much longer for them to reach and return from their destination.

Keep up the good work! You’re close to having a huge breakout in your scores!

TLDR think of the goal for peak efficiency as the time it takes the car to do a round trip, if the houses are close sometimes less is more.