Continuity mistake: When Harry is talking to a police woman at the station, about going through the police files, the woman's bangs are messed up. When the camera pans back to her, every hair is in place.
Revealing mistake: In the scene in the subway Denis Hopper has again used an explosive jacket like that used at the start of the film, which is detonated if the remote trigger is released. However when on the subway train, Denis takes the remote back from Sandra Bullock and it is seen that the trigger is quite obviously released and Denis pushes it back in.
Factual error: When Jack is under the bus, he manages to puncture the gas tank by sticking his screwdriver into it. There is no way a simple screwdriver could punch a hole in the solid metal tank, even if Jack took a forceful swing at it like he had when he lost his balance on the trolley.
Revealing mistake: When Howard Payne's house explodes, a wire is visible as it pulls back one of the police officers who gets "blown back" by the explosion.
Continuity mistake: Jeff Daniels' character gets shot in the thigh by his partner. Later, when he gets his award, it is the opposite leg that has a cast on it.
Continuity mistake: When Jack is chasing the bus on the freeway in the Jaguar, an overhead shot is shown of the bus with three cars around it, but in the next shot of the traffic, the road is full of traffic which is surrounding the bus, which is highlighted by Jack having to swerve around the cars.
Continuity mistake: Near the end of the film when Keanu Reeves and Dennis Hopper are wrestling on top of the subway, if you watch Keanu's left wrist you notice he is wearing a watch. Yet throughout the scene it is obvious that the stunt double has no watch, because in the extreme action scenes, there are no signs of it anywhere on his wrist.
Factual error: Harry is a LAPD SWAT team member. SWAT trains and trains and trains, then exercises and trains some more. Harry would not be investigating the case as shown when he asked to see the files for the last 10 years. If he was on desk duty for his injury, yes, he could be working the investigation. But soon after, he was on the entry team at Payne's house. That would have required more prep work by the SWAT team that Harry would have had to be doing instead of looking through the files.
Factual error: In the bus freeway gap jump, a second after driving off the freeway edge, the bus has fallen beneath that edge level of the freeway. It would be impossible for it to have regained altitude to be above the freeway on the other side. It would have hit at best halfway between the wheels of the bus, if at all.
Factual error: As long as gravity is a constant, there is no physical way that the bus (traveling at 68 mph) could possibly jump the level, 50-foot horizontal gap in the freeway. Even at triple or quadruple that speed, the bus would invariably drop vertically by as much as a meter, with catastrophic results.
Revealing mistake: Before Jack rips the door off the Jaguar, he speeds ahead of the bus and then opens the driver's door at highway speed. At 50 MPH there would be a lot of air resistance, yet Jack opens the door effortlessly.
Other mistake: As Traven is about to slide under the bus on the small trolley, you can see his feet are only just going to get under the bus. Cut to a camera shot from the side, and now the front of the bus is significantly higher.
Continuity mistake: When Jack handcuffs Ray to the metal handrail, Ray's right wrist has the double strand bars facing up and single strand bar facing down, but when Jack tells the passengers about the gap and then uncuffs Ray before the jump, the handcuff's single strand bar is facing up on his right wrist.
Visible crew/equipment: After the first bus blows up, Jack talks to Howard on a payphone. The boom mic is reflected in the receiver.
Visible crew/equipment: In several shots of Tuneman in the Jaguar, you can see camera lights reflected in his sunglasses.
Continuity mistake: After the bus has left the freeway and enters the city for the first time, there is a scene where Annie is driving the wrong way down a street and Jack can be seen standing right next to her. She pulls the bus onto the right side of the road and Jack puts the cell phone to his ear. In the next shot, he repeats the same action.
Visible crew/equipment: When Jack is talking to Howard from the pay-phone, you can see the boom microphone's reflection in the phone in several shots.
Revealing mistake: When Jack is fighting Dennis Hopper on the roof of the subway train, a piece of paper falls off one of them and then stays surprisingly still considering they're on a speeding subway train.
Answer: If they had, there might have been the possibility that to get to these routes they would have to go down a different road and depending on which route they take they might have to slow down to make the turn which would likely cause the bus to drop below 50 mph. Better to just keep going straight and keep the bus going. There's also the possibility that had they taken a different route, they would have to deal with a lot of traffic especially if there was traffic stopped at a red light. By using the highway, there'd be no traffic lights and less traffic to deal with.