Took me a while to find this fix online so I've posted it here to help you!

Apparently - and this starting happening out of the blue for me as well - the game just starts freezing up during the saving process in your driving career. It can happen at any time and anywhere in the game - EVEN AFTER RACES - so tread carefully. I can't take responsibility for you screwing up your computer! I only post this fix because it worked for me. There doesn't even seem to be an explanation by Atari as to why this happens but there is a fix to help you get back on the road.

It is as follows and it's as simple as deleting a hidden Windows file (this covers XP only BTW, Vista fix might be a bit different - maybe now, I don't know) in the Test Drive Unlimited application data folder...

Goto My Computer. Find your C drive.

Documents and Settings >> All Users >> Application Data >> Test Drive Unlimited

You'll see a file there called "radial.cdb". Don't see it? You'll have to tell Windows XP that you want to see hidden Windows files. So do this:

IF YOU DONT SEE THE FILE: Goto your "Control Panel" and open up "Folder Options >> VIEW". Now UNCHECK "Hide Protected Operating System Files (Recommended)". You'll get a Windows warning but proceed cause you know what you're doing (don't you?) :)

Now delete the file "radial.cdb".

You should be good to go now. This worked for me after I was experiencing the same issues you're going through. I thought this great game was hosed from me ever getting to play it again so I was thrilled to find this fix.

Happy driving!