I'm so exhausted that I'm thinking about purposely  crashing my car so I finally get a chance to rest.
I'm alarmed to hear you're feeling so desperate!
Yes, I know that if I die I can get rest.
I'm sorry that you are feeling that way, but crashing your car isn't the answer. Not only will you hurt yourself, you could hurt others, too. If you're having issues coping with exhaustion, it would be a good idea to talk to a doctor or mental health professional.
If I'm dead it doesn't matter.
It would matter to the people you injured, and all of the people who are saddened by your death. I really think you should not crash your car, and instead talk to someone about how you're feeling, as they'll be able to help you.