Missouri Legal Update
2022 Lesson 1: Traffic Law Enforcement
This is an online legal studies course for law enforcement officers. The lesson addresses state and constitutional law governing police officers’ initiation and conduct of traffic stops.
Section one examines the topic of the source of state and local power to pass and enforce traffic laws, including inherent state police power, statutory enactments governing the state police power, statutory grants of policing authority to political subdivisions, and the prohibition against local ordinances conflicting with state traffic laws.
Section two examines the topic of constitutional limitations on traffic stops, including the amount of evidence necessary to establish reasonable suspicion for a vehicular Terry stop (including evidence known by each officer with a connection to the stop), the type of offenses for which a stop may be made, whether an officer must issue a citation in order to have reasonable suspicion or probable cause to make a stop, the permissible duration of a stop, and the permissible scope of the stop. This section also addresses the constitutionality of several types of vehicle checkpoints.
Section three examines the topic of statutory limitations on traffic stops in counties, cities, towns, and villages, including prohibiting political subdivisions from having quotas for citations, limitations on the amount of fines and being held in custody for traffic violations, prohibitions on racial profiling and reporting requirements, and prohibitions on creating speed traps.
Section four examines the topic of miscellaneous traffic laws, including the duty to drive in a careful and prudent manner, signaling requirements, prohibitions on driving while intoxicated, and whether these laws may be enforced on private land or only on public roads and highways. This section also addresses traffic procedures for police responding to emergencies.