Trivia: In this movie the only reason why Howard Payne is trying to blow the elevator and the buses is because he wants money. He also gets very upset when the paint explodes in the bag. If you look on the back of bus 2525 there's a green sign that says "Money isn't everything (Yeah Right)".
Trivia: The famous "Dukes of Hazzard" sequence was the filmmakers' wry commentary on the uncompleted state of Interstate 105, which had become a running joke among LA motorists. It was finally (and quite uncoincidentally) completed in late 1993 shortly before the film's release, years behind schedule.
Trivia: When the bus crashes into the plane at the end, the company logo on the plane is "Pacific Courier." This fictional company name also appears in "Die Hard"--it's on the truck the terrorists show up in (except Karl and Theo, who arrive by car). Jan de Bont, who directed "Speed," was DP on "Die Hard."
Trivia: The bus number is 2525. 25+25=50. The bus has to stay above 50mph.
Trivia: Dennis Hopper's line about Pershing Square being the "pickup spot" (for his ransom money) was a double entendre. For decades, Pershing Square has been a notorious locale for soliciting gay sex.
Trivia: When we first see the bus in the airport you see a plane go over the bus. That scene took 50 takes.
Trivia: Although Keanu Reeves states in the film that the freeway gap is 50 feet, the missing section shown in the digitally-retouched freeway shot is actually 177 feet, when measured against other known structures. Jan de Bont's digital effects team realised that a properly-measured 50-foot gap would appear far too small for the desired shot, so they made the gap more than three times larger.
Trivia: When they show the gap the bus has to jump for the first you see birds fly through the gap. The birds were digitally edited in and the gap was digitally added on to a real bridge.
Trivia: The first bus explosion nearly ended in disaster - the real bus that Jack waves goodbye to turned off while out of shot, then the camera moved around to see the prop bus in its place (towed by a car) that was packed with explosives ready to blow up. But a woman ran onto the set, thinking she'd missed her bus, and hopped aboard, almost missed by the crew as they were at a safe distance. John Frazier, the effect supervisor, spotted her and fortunately stopped the foreman from triggering the blast.
Trivia: The famous line "pop quiz, hotshot" doesn't actually have a definite writer. The original script was by Graham Yost, but Joss Whedon was brought in to rewrite it (unhappily uncredited per WGA rules) and wrote most of the dialogue. He said the line was already in the script, while Yost denies writing it and said it was Whedon's. Most likely it was written by another script doctor, Paul Attanasio, but he doesn't recall writing the line either.
Trivia: Joss Whedon was brought in to work on the original script, and despite being responsible for about 90% of the film's dialogue, didn't get a writing credit due to WGA rules at the time. He changed Alan Ruck to be more sympathetic, and created the scene after the elevator rescue when the team is celebrating, but all the characters, story beats and action were from the original writer Graham Yost.
Trivia: In the original script. Jack's partner Harry would turn out to be the mastermind behind the bus bomb (with Dennis Hopper simply being his accomplice). When Ed Harris, who was originally cast as Harry, left and Jeff Daniels got the role, producers felt that Daniels was too nice and likeable to be truly convincing as a villain and changed it to just make Hopper the sole baddie.
Trivia: At the beginning of the movie, Keanu Reeves breaks some glass on the door of the bus. This was not scripted; it was purely an accident and kept in the final print.
Trivia: The onramp to the freeway where Jack first drives on, passing vehicles to catch up to the bus, is actually the same location on the 105 freeway by the airport where the bus exits later in the film (where they exit for the airport). There is even a fake "Interstate 10" sign added if you look carefully to give out the illusion they are in Santa Monica getting on the 10 freeway.
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.