Factual error: After mounting armor in the bus they are approaching Phoenix on a two lane highway from the northwest. When entering the city they are shown coming around South Mountain on Interstate 10 from Tucson from the south.
Audio problem: After the bus crashes to a halt on the courthouse steps, the gunfire stops. A few seconds later, a bullet hole opens up on the side of the bus - but there is no sound.
Trivia: One of the passengers seen getting off the hijacked bus is the same actor who drove the ambulance and got blown up in the rental car (blue '74 Plymouth).