This has been asked before already regarding recently I would encourage you to do some research around and see which helpful plugins that you come across and try for yourself.
Some plugins will create much more - detailed tracks, however the suggesting above could possibly work, I would recommend using parts and rotating them different degrees depending on how large the race track will be featuring corners, turns, and more. Archimedes plugin might be something your looking for, however you’ll need to learn the plugin before attempting to create roads. It’s great for creating certain parts put it really depends on how large your wanting to make it.
Here is a thread that goes into more depth it might be something to take along the process and learn from there: