Other mistake: At the end of the first race scene with the four cars, Brian spins out. As he spins out you can see that the Asian guy in the white car comes toward him, but when Brian completes the spinout the white car doesn't pass him. (00:20:27)
Other mistake: At the climatic railroad grade-crossing scene towards the end of the movie, the black locomotive (A modernized EMD GP40) is moving entirely too fast for the track's curvature and the height of the rails. The track's rail are of light gauge, for yard rails and switching only. (You see the container yards in the background of the final scenes.) The camera shots also show a zig-zag curve in the railroad tracks - which would definitely be taken at a lower speed. You actually see the locomotive rocking at one point. Good dramatic movie scene - suicidal railroading. Furthermore, the locomotive's driver would have seen a sign for "grade crossing" ahead of the crossing and slowed his train down according to railroad regulations. He would have made two long blasts on his horns, a short and then a long - not a continuous tone as played back in the movie. When a grade crossing is just after a curve - there are severe speed restrictions in effect - 5mph or less - so there is a hope that the train can stop or slow down, should someone cross the tracks at the wrong time. The interior shot of the locomotives cab is wrong. The interior cab of a locomotive is not symmetrical. The old standard cabbed EMD's have two windows in the center where-as the interior shot only shows one center window. The locomotive's parked windscreen wipers are also not shown from the inside. (01:37:25)
Other mistake: In the scene where Vin Diesel's Dodge Charger crashes, the blower is bolted on the bonnet. That is impossible because the blower is actually bolted onto the engine and it should shake with the engine's movement. (01:37:40)
Other mistake: When Brian is practising in the stadium lot, when he shifts up there is a shot of his speedo indicating the car jumps from approx 127mph to 140mph in the space of a second. Questionable as that acceleration rate is, rolling on from that speed, in the 2nd subsequent scene right after Brian tells Harry that he needs NOS, he says "my car topped out at 140 miles per hour this morning". Although it is true that we don't actually see the needle go past 140mph, there is no way a vehicle would or could accelerate at that rate and then suddenly plateau at its terminal velocity. All vehicles' acceleration rates decrease rapidly as they approach top speed. At the rate Brian's needle was moving from 127 to 140mph, one could speculate that his actual top speed would be more like 200mph. (00:03:25 - 00:09:30)
Other mistake: When the cops get prepared before arresting Johnny Tran, a cop inserts a magazine into his M4. If you watch the rifle's chamber, you can see the green plastic thing that is at the top of the spring, hence the magazine is empty. (01:01:47)
Other mistake: When the first trailer/truck is hijacked and the harpoon is shot in through the window into the seat, you can see the driver is very clearly looking out the side window next to him instead of looking at the hijackers in front of him. It's almost as though he doesn't know that the others are there! He also looks incredibly relaxed and not at all worried about the fact that a guy is climbing up a rope into his cabin when there is a lot of expensive video equipment in the back of his trailer. (00:01:53)
Other mistake: Not necessarily a mistake, but still odd. When Brian pulls up with the Supra on the flatbed, and he pops the hood, the wrong engine is shown. Yes, Jessie says it's a 2JZ, which is technically correct, but it's the naturally aspirated version 2JZ-GE, not the twin turbo 2JZ-GTE. Are we supposed to believe that they replaced the engine and the transmission of this car before it was done? It would have been cheaper and easier to find a twin turbo version with the right transmission.
Other mistake: When Brian shoots Tran, two bullet wounds appear in his shirt at the same time, which is impossible, because he was only shot by one person with a handgun. They also appear way too late.
Other mistake: When it shows SWAT getting ready atop a parking garage to raid Johnny Tran's house, there is a shot of a SWAT officer, in an aiming stance with an M4, but his gun has no sights or scope.
Other mistake: When Brian is evading the cops after picking up Dom, he comes out of a side street and is honked at by a Volvo station wagon, which then ends up crashing into the cop car following. Thing is, the light was red for the Volvo the entire time, so they shouldn't have been rolling through the intersection, much less honking at Brian like he was in the wrong.
Answer: There are two ideas of why the police did not come around. Firstly they might have found out after the car chase that Brian was an undercover cop so it would be more effective to allow him to try and discover information instead of going around and arresting Dom. The other idea is that the police might not have enough to arrest him. Dom was not the one driving when they found him and other than racing, it might be tough to arrest him.
Lummie ★
Cops are usually completely unaware of an undercover cop's identity. The more, realistic reason is that the cop didn't ID Dom and since Brian's car was later destroyed, there's nothing for them to investigate. Afterwards, they might ID Dom, but there's an investigation on him, so they'd leave him alone.