If the CPU affinity fix doesn't work for you, or you want a more permanent, hassle-free solution, you can simply remove the police cars from the game entirely. This method was shared by a user on the French gaming forum JeuxVideo.com and has been effective for many.

Corrupted or missing original vehicle files can prevent the police models from loading.

You hear the sirens, you see the flashing lights floating in mid-air, and you get the "Busted" notification, but the actual cruiser model is missing. It turns the game from a high-speed chase into a ghost hunt.

The phenomenon of in Test Drive Unlimited (TDU1) is a notorious bug caused by modern hardware running the game too quickly. This issue typically manifests as players colliding with unseen obstacles or suddenly being chased by a siren that has no physical source on the road. The Core Cause: High Frame Rates