If you got involve in minor or major incident or accident never ever leave the scene, If you leave even you are not in fault, all faults will be yours. Park you car nearest safest place if you can park, let the other person know you not driving away. Call 911. Never ever express you were in fault (even it is your fault, insurance will deal it), choose right word. Exchange information for your record. Driver's Name, insurance information and telephone number, car number plate, time of accident.

Once police is on the scene, he or she will take information from both of you. If you see someone who had witnessed the accident, you may request him or her did she see and if needed can you help me.

Even someone hits you in the rare, if you see nothing happened to you and  your car, do not leave the scene , talked to him/her and see if his or her car has any damaged, he or she may claim on you follow the same procedure as above. You will find crooked people every where.