The most important matter in determining who is at fault is investigating who was negligent. For motor vehicle accidents it is determined in accordance with written driving rules, the rules that regulate how people must drive and provide guidelines by which liability can be measured in case of an accident. In order to take the driver’s license test the rules and laws of the road must be learned. In each State there are Vehicle Codes that apply to cars, automobiles, bicycles and pedestrians. The negligence in regard of those rules serve the purpose of determining of who is at fault of an accident.