The race maps are created by END. I was going to port his maps to single player, several race maps are not lessy objects.

I was going to set mario kart or gta san andreas race in single player. I done with maximus map with 7 racers and crowds but no laps yets

I really can't make good racetrack maps cause I'm too picky with the buildings highly, and free-roam or war zone related thing.

AIRBREAK.cs is included, all you got to do is the press TAB+Q to airbreak in case you fall under the map.

To access it you'll need to type RACE
When you want to exit the map type EXIT it will clear the map. (sorry forgot to warp back to san andreas) too busy with that stilwater' thing saints row of course

Beside you'll need open adjuster limter or fastman's adjust limiter to set to 999999999 mission cleanup I recommand to take both.
https://gtaforums.com/topic/733982-fastman92-limit-adjuster/
https://gtaforums.com/topic/736512-open-limit-adjuster/

go to END that create his awsome race maps
https://www.youtube.com/watch?v=kfgYN0B_AOI