If you are involved, yes. Your duty is to get out of the car and offer help, check to see if there is damage to the other person's car. It is also your duty to make sure no-one is hurt. If you don't and you decide to keep going, you're what they call a "hit and run" suspect. If you are not involved in the accident, whether or not you have a duty to stop and render aid depends on the laws of each state.