When you have a car crash do you go to jail?

It would depend on the situation. In most cases, no, you won't go to jail.

If you are intoxicated, or in a stolen car, or driving without a license, yes, you could certainly go to jail. And you could certainly be fined and/or lose your license.

It depends how you where driving and if you meaning to cause the crash and there are many other legal issues.

you will go to jail if you are a drunk driver or if it was a hit and run or if you were drug taking or underage. You can also get arrested but only for a few hours until they uncover the story and then the other person can sue you or claim on you meaning you get fined. If you weren't the one that crashed the car then you have nothing to worry about and you can also claim expenses from the other driver.