School crossing control devices are an extension of a Safety Education Program, applicable to both the pedestrian and motorist. Every request for school crossing protection is considered by the Public Works Department, on its own merits and treated consistently with other similar school crossing sites. Traffic controls necessary in a school area adjacent to a major arterial street may not be applicable on a residential street. However, a uniform approach to school area traffic controls is maintained to assure the use of similar controls for similar conditions. This promotes a uniform behavior on the part of both the pedestrian and motorist.
Generally, requests can be classified under one of the following categories:
No protection is generally required at locations where only a few children are crossing the street and the opposing vehicle volumes and speeds are such that more than adequate safe crossing opportunities exist. Crossing locations such as these are typical of many residential streets. At these locations the child is primarily dependent upon his or her early safety education along with normal driver caution.
Type "A" Protection
Type "A" Protection is necessary at locations where there is a high number of children crossing the street, but the opposing vehicle volumes and speeds are such that at least one safe crossing opportunity per minute exists. Crossing locations such as these identified by a marked and signed crosswalk, are typical of some residential streets, collector streets and some low-volume arterial streets.
A marked and signed crosswalk, when installed in conformance with the minimum standards, informs both the school children and the driver that the location is an authorized school crossing. This type of control helps in focusing a driver's attention to one location, where there is a reasonable expectation of children being present. A minimum rating value of 10.0 is required for consideration of a marked and signed crosswalk. The crosswalk rating is derived by using a formula which includes the pedestrian volume, vehicle volume, speed and street width. Details of the crosswalk rating procedures are described in the area titled, "School Crosswalk Rating Criteria".
Type "B" Protection
Type "B" Protection is necessary at locations where a moderate or high number of children crossing a street are subjected to long delays due to the infrequent occurrence of natural, safe crossing opportunities in the traffic stream. When the delay becomes excessive, children may become impatient and endanger themselves by attempting to cross during a less than adequate gap or crossing opportunity. Crossing locations such as these, identified by Pedestrian actuated signals, are typical of major arterial streets with high volumes and speeds.
Pedestrian Actuated Signals:
New School crossing signals may only be installed at mid-block crossings, where adequate trial of less restrictive controls with satisfactory observance and enforcement have failed to assure a safe crossing. To be considered for a school crossing signal, a location must meet the minimum requirement for each of the following three conditions:
- Safe Gap: The most important factor that controls the crossing of a street by a pedestrian is the available "safe gap". A "safe gap" or break in traffic is the total time required by a pedestrian to walk from one curb or edge of roadway to the opposite curb or edge of roadway, also included in this time is the pedestrian perception and reaction time. When the delay between safe crossing opportunities becomes excessive, an artificial method (traffic signal) can be introduced to provide the necessary breaks in traffic.
A street crossing delay is considered excessive when the number of safe gaps in the natural traffic stream, during the period that children are using the crossing, is less than the number of minutes in the same time period. In other words, if at least one safe crossing opportunity per minute is not available, the delay is considered excessive.
- Crosswalk Rating: A minimum crosswalk rating value of 100 is required for consideration of a school signal. The rating procedure is the same as that for a Marked and Signed Crosswalk, described in detail in the area titled, "School Crosswalk Rating Criteria".
- Minimum Pedestrian Volume: A total of 20 students crossing within the crosswalk during the peak A.M. and P.M. 1/2-hour periods are required for consideration of a school signal. If there are less than 20 students during the peak periods, but few safe breaks in traffic and a high exposure rating, alternate means of getting the children safely across are pursued before considering a traffic signal.