Continuity mistake: In Jack's first attempt to stop the bus, he runs alongside it waving his badge. Between shots, his badge switches from right hand to left (before he turns around to shout "Stop" at oncoming traffic). (00:34:50)
Continuity mistake: When the bus passengers notice Tuneman's Jaguar approaching, watch how Stephens (the tourist wearing a blue shirt and sunglasses) changes his position between shots. From the outside we can see him minding his own business and facing the front of the bus at first, possibly reading a book on his lap. However in the following shot he's suddenly got both arms leaning over the seat back and his head turned left. (00:36:25)
Continuity mistake: In the scene where Jack pulls a gun on Tuneman, watch as Tuneman's hands change positions on the Jaguar between shots. At first he grabs the top edge of the windshield when pulling himself up to switch seats, but then his hands are placed much closer to the windshield's center all of a sudden. (00:35:10)
Continuity mistake: When Payne is about to board the subway train with Annie, he fires warning shots into the air and she ducks her head in response. But she repeats the same action in the next shot. (01:39:30)
Continuity mistake: When Payne is in a hideout watching the news unfold on numerous TV sets, he hears one reporter mention that a Los Angeles police officer (Jack) boarded the bus from a moving car. Right here we can see a reflection of Payne in the TV screen, which shows him placing his right hand over his mouth. In the following shot of Payne's face, where he says "Oh would that be you Jack?", his hand isn't anywhere near his mouth. (00:44:20)
Continuity mistake: When Tuneman realizes that he's about to crash into some barrels of water near the exit, he ducks for cover but, in the next shot, we see him sitting upright again. (00:40:00)
Continuity mistake: After telling Tuneman that he needs to board the moving bus, Jack pushes the Jaguar several car lengths forward so that he'll have ample distance to smash the door off. Meanwhile, we can see dotted white lines on the pavement between the Jaguar and the bus. But look over Jack's shoulder as he says "Are you insured?" and notice how two pairs of solid yellow lines have momentarily taken place of the white ones. (00:39:05)
Continuity mistake: When Annie tries flagging down the bus, it changes position on the road. You can see how its right set of wheels instantly shifts from one side of the solid white line to the next between frames - at the point where it begins to decelerate. (00:31:05)
Continuity mistake: In the shot where Payne gives Jack permission to unload Sam from the bus, listen closely to the male news anchor on the immediate right. He reassures his viewing audience that the bus hasn't exploded, although a woman was caught in the blast and fell. This report airs roughly two minutes before the incident even takes place. (00:57:05 - 00:59:15)
Continuity mistake: After Payne loses his head, Jack says "Yeah? Well I'm taller." Between shots, Jack's right arm instantly goes from resting at his side to a lifted position. (01:44:35)
Continuity mistake: An obvious stunt double is briefly visible pushing a baby carriage full of cans into the crosswalk as Annie unknowingly rams the bus into it. Initially we see an older woman pushing the carriage along after chatting with her friend. In a view from within the moving bus's front window, however, a much younger woman has briefly taken her place for a couple of shots. (00:50:05)
Continuity mistake: The Suburban that swerves onto the LAX runway to retrieve Jack has no scaffold equipped on its driver's side, but we know for a fact that moments later Jack actually exits the bus and steps safely onto one. Somehow the Suburban has managed to gain a scaffold at cruising speed, but this couldn't have possibly happened unless a different, identical-looking vehicle with a scaffold pulled up at some point during the scene to take its place. (01:10:05 - 01:11:15)
Continuity mistake: When Jack starts tying a rope to the access panel, he faces the back of the bus initially but manages to turn completely right between shots, facing the side windows all of a sudden. (01:29:20)
Continuity mistake: When the crane breaks free from its bolts and starts flying towards some ventilation windows, it obliterates the upper pair. However in the next view from within an air duct, both of these windows just swing open freely as the crane busts through, and yet they barely appear to have suffered a scratch or bend in the process. (00:15:00)
Continuity mistake: When the crane is torn out of the floor and flies towards the ventilation window, from a shot behind, the holes on the base (where the screws used to be) are gone. (00:14:30)
Continuity mistake: In the scene where the Pacific Courier Freight plane gets blown up, you can see that it is being towed alongside another plane, and some people standing/walking around next to it. In the next shot, where we see the camera moving closer and closer to the plane from the bus's perspective, the runway the plane was just being towed on is gone, as is the plane it was going past a moment ago along with the people. There was no time between shots for the plane to have been moved so far away. (01:30:35)
Continuity mistake: In a camera shot from behind the bus, it shows Traven moving the Jaguar in front of the bus. In the next camera shot from the front, it shows Traven moving the Jaguar again in front of the bus. He'd already completed the move in the previous shot.
Continuity mistake: At the beginning of the movie we see Keanu Reeves taking Jeff Daniels "out of the equation" by shooting him in the leg. We realise it's a serious injury as he requires the use of a cane when receiving his medal. However later on in the movie when they move in on Dennis Hopper's home, which takes place the next day, Daniels is part of the assault team and has no cane, no limp and is obviously very mobile.
Continuity mistake: When Jack drives on the shoulder, honking his horn to let people know that he's coming, he's pressing on a silver ring, which is the horn, but in the next shot, it's gone. While the ring only covers half the wheel, as he's going almost entirely straight it should always be in the same position. (00:31:35)
Continuity mistake: After the first bus explodes, Jack ducks for cover near his Bronco. Soon he looks over at the burning wreck and stands up - but notice that he's still crouched down in very next shot. (00:27:50)
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.