In San Diego, Apone will give you words of encouragement after races, even though you have not met him yet.
The 1996 Chevrolet Impala SS was not used as a police car in the U.S.; its sister car the 1996 Chevrolet Caprice was. However, by the time the game was released, 2005, most police departments had stopped using them and replaced them with the 1998 and above Ford Crown Victoria Police Interceptor.
The 1996 Chevrolet Impala SS was not commonly used as a taxi in the U.S.
On the console versions of the game, the Renaissance Center in Detroit is missing the General Motors signage. However, on the PSP version of the game, the signage is present.
The San Diego Police Department cars are using regular civilian license plates, rather than the "CA EXEMPT" ones that they should be using.
The Detroit People Mover is only one set of tracks wide in real life whereas in the game it's two.
Some racers have the same exact license plates during races.
In Detroit, a Hummer billboard's diffuse texture is displayed backwards/reversed.
The in-game listing for the Unwritten Law song "F.I.G.H.T." lists the band as Unwrittten Law with three t's.
North American-spec Honda Odysseys and Toyota Tacomas can be seen driving around Japan in large numbers.
All the Japanese racers in Tokyo have U.S. license plates on their cars.
The San Diego Gaslamp quarter arch is directly in front of PetCo Park in game when in real life it is a couple blocks away.