1. Example: If the person is jay-walking in the dark with dark cloth on busy street. You will not have criminal negligent. However, his family can go after your money.
2. Example: If you were speeding or DUI or similar condition, then you will have criminal negligent. You will go to jail.
The key is to make sure somebody can prove that you did your best to avoid hitting the person. Then you will not have criminal negligent. However, state law on jay-walking are very different. If you are in NV, you are lucky.