This Commentary analyzes the traffic ordinances of the 100 largest cities in the United States. It will compare those ordinances with the Model Traffic Ordinance, and with some provisions of the Uniform Vehicle Code, especially those which were formerly part of the Ordinance. It will identify and describe provisions found in the 100 city ordinances which are not part of either the Model Traffic Ordinance or the Uniform Vehicle Code. The Commentary will broadly assess the scope of traffic regulation in the 100 cities and the authority for such regulation, and it will narrowly discuss the substance of individual sections commonly found in the 100 ordinances. In general, the purpose is to present a comprehensive picture of the status of municipal traffic regulation in the United States. Both the Model Traffic Ordinance and the Uniform Vehicle Code are maintained by the National committee on Uniform Traffic Laws and Ordinances, an independent, non-profit, voluntary association.