I used to play the demo of Test Drive III. It only had one map I believe. But I loved that it was a sandbox, so you could drive anywhere. I specifically remember following along the railroad. It was way ahead of its time back then.
Test Drive 2 (and 1) used a pseudo-3D renderer with scaled sprites (see https://www.mobygames.com/game/2107/the-duel-test-drive-ii/s...)
TD3 used a 'real' 3D engine, but as a result it needed a beefy machine for the day. Driving felt a lot slower too, I never found it as much fun as TD2.
On the other hand most maps have loops and I would regularly get lost, unable to finish it...