Tracks are built in various sizes which include standard, medium and wide. But, when it comes to building your own RC track, the sizes, shapes and variations are really up to you - it's your track - build it the way you want! So first thing's first. When it comes to building your own RC car track, make sure to take your budget into consideration.
Planning on updating everything next season. Track is still under construction. My shortcourse truck does pretty decent with the lane width, although when I race at an 1/8 scale buggy track with my SC Truck, those 15 to 18 ft lanes feel extremely wide.