Last Updated: May 11, 2009 at 10:16 am
By: Melissa Torres
Many drivers around the Valley ask why there aren’t traffic lights at certain intersections– or requesting studies for ones in busy areas that don’t have one! With new areas still developing around town, not to mention all of the construction work– you may have found yourself stuck in traffic wondering- “why isn’t there a traffic light here?!”
So here’s the break down! When determining if an intersection needs a traffic light, a study is conducted. During the study, there are eight “traffic volume warrants” or determining factors that are looked at. All of these combined could determine if a light is needed and will be installed or not. At least one of these needs to meet the study in order to have a traffic light installed. However just one- will not always mean a traffic signal is required to be built. It depends on the intersection and what the research shows.
Warrant 1 - Eight-Hour Vehicular Volume Warrant. The volume of the traffic on the major and minor streets entering the intersection must be above a certain number during an eight hour time period on a typical day.
Warrant 2 - Four-Hour Vehicular Volume Warrant. The volume of the traffic on the major and minor streets entering the intersection must be above a certain number for a minimum of four hours on a typical day.
Warrant 3 - Peak Hour Warrant. The minor street traffic for a facility that attracts or discharges large numbers of vehicles of a short time suffers major delay or exceeds a certain value for only one hour of an average weekday.
Warrant 4 - Pedestrian Volume Warrant. The volume of pedestrians crossing a major street exceeds a certain number.
Warrant 5 - School Crossing. At an established school crossing, a traffic signal can be placed if the frequency and number of adequate gaps in the vehicular traffic for the number of students to safely cross does not exist.
Warrant 6 - Coordinated Signal System. To maintain the proper grouping of vehicles and to effectively regulate the group speed.
Warrant 7 - Crash Experience. When less restrictive remedies and enforcement has failed to decrease the crash rate.
Warrant 8 - Roadway Network. To encourage concentration and organization of traffic flow on major streets.