I have to rate it 5 stars because I play on it all the time. It is a good vehicle endurance test, as accelerating hard, braking hard while on speed bumps, then steering sharply can be tolling on the engine thermals, brakes and suspension. Just a few things... The corners, for a highway, are a bit too sharp, and even as a road, 50km/h speed limit around turns causes vehicles to run wide. And the ai loves to drive on the wrong side of the road and run into walls.
However, I love this type of map (simple roads with turns) and only a few others of its kind exist (eg. Matrix Freeway)