system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How come standard cars aren't fitted with roll cages to make them safer during accidents?
gpt
Ever wonder why race-cars doesn't have doors that open?

It's the rollcage that's in the way. There's (at least) two massive metal tubes that goes through where the door is.

However, your standard car has a rollcage, of sorts. The chassis is designed in such a way that it acts as a deformable rollcage.

Why a deformable roll-cage?  Wouldn't a stiff one (like in the race-cars) protect you better?
Well, yes, and no. A stiff roll-cage makes the whole car very stiff, making you absorb a lot more of any impact. You want your car to crumple as much as possible (without crushing you). That means that you get to absorb less of the energy from the crash.