Here is a retouched version to try to improve some details: transparent walls of collision added behind the rails. Red and yellow tire batteries in collision format. But strangely, despite the good name of the objects, from some angles, the car sometimes happens to cross the wall ... sorry. Fences correction. They remain voluntarily without collisions. I wanted to add a collision sound when we crossed ... but I did not succeed. The map is now operational. The hotlap is working well now. Voluntarily I did not add a starting grid to ride in a fast race.