In the United States, the criteria for installation of a traffic control signal are prescribed by the Manual on Uniform Traffic Control Devices (MUTCD), which defines the criteria in nine warrants:Section 4C. Manual on Uniform Traffic Control Devices (2009 Edition). Mutcd.fhwa.dot.gov. Eight-hour vehicular volume. Traffic volume must exceed prescribed minima for eight hours of an average weekday. Four-hour vehicular volume. Traffic volume must exceed prescribed minima for four hours of an average weekday. Peak hour volume or delay. This is applied only in unusual cases, such as office parks, industrial complexes, and park and ride lots that attract or discharge large numbers of vehicles in a short time, and for a minimum of one hour of an average weekday. The side road traffic suffers undue delays when entering or crossing the major street. Pedestrian volume. If the traffic volume on a major street is so heavy that pedestrians experience excessive delays in attempting to cross it. School crossing. If the traffic density at school crossing times exceeds one per minute which is considered to provide too few gaps in the traffic for children to safely cross the street. Coordinated signal system. For places where adjacent traffic control signals do not keep traffic grouped together efficiently. Crash experience. The volumes in the eight- and four-hour warrants may be reduced if five or more right-angle and cross traffic turn collisions have happened at the intersection in a twelve-month period. Roadway network. Installing a traffic control signal at some intersections might be justified to encourage concentration and organization of traffic flow on a roadway network. Intersection near a grade crossing. A traffic control signal is often justified at an intersection near a railroad crossing, in order to provide a preemption sequence to allow traffic queued up on the tracks an opportunity to clear the tracks before the train arrives.
in the united states the criteria for installation of a traffic control signal are prescribed by the manual on uniform traffic control devices (mutcd) which defines the criteria in nine warrantssection 4c manual on uniform traffic control devices (2009 edition) mutcdfhwadotgov eight-hour vehicular volume traffic volume must exceed prescribed minima for eight hours of an average weekday four-hour vehicular volume traffic volume must exceed prescribed minima for four hours of an average weekday peak hour volume or delay this is applied only in unusual cases such as office parks industrial complexes and park and ride lots that attract or discharge large numbers of vehicles in a short time and for a minimum of one hour of an average weekday the side road traffic suffers undue delays when entering or crossing the major street pedestrian volume if the traffic volume on a major street is so heavy that pedestrians experience excessive delays in attempting to cross it school crossing if the traffic density at school crossing times exceeds one per minute which is considered to provide too few gaps in the traffic for children to safely cross the street coordinated signal system for places where adjacent traffic control signals do not keep traffic grouped together efficiently crash experience the volumes in the eight- and four-hour warrants may be reduced if five or more right-angle and cross traffic turn collisions have happened at the intersection in a twelve-month period roadway network installing a traffic control signal at some intersections might be justified to encourage concentration and organization of traffic flow on a roadway network intersection near a grade crossing a traffic control signal is often justified at an intersection near a railroad crossing in order to provide a preemption sequence to allow traffic queued up on the tracks an opportunity to clear the tracks before the train arrives