There are different classifications of Hit And Runs offenses. A Hit And Run can happen even if the driver does stop their car and check to make sure everyone is alright.
If you are ever involved in an accident whether you are at fault or not. Make sure you stop your vehicle, see if anyone needs medical attention, then exchange information. That includes Name, Address, Driver's License Number and the License Plate Number of the car involved.
If you are in an accident and the driver of the car is unwilling to exchange information--call the Authorities immediately