Writers and animators clearly aren't familiar with anything to do with demolition derby. If they did, they would have at least left glass out of the cars. One of the first things that's taken off a car before it can take part in a demolition derby is the glass. Glass represents a hazard when it breaks and it would hinder a driver making a quick exit from a stopped car. Demo derbies usually render doors useless, and in real derbies, the doors are wired shut.
And glass is just one of the things that has to be dealt with to run a car in a demo derby. It would have been easy to animate.