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3. TOOLBOX OF TRAFFIC CALMING MEASURES Traffic calming is defined as physical measures that reduce the negative effects of motor vehicle use, alter driver behavior, improve safety for non-motorized street users, and improve neighborhood livability. The following pages describe and illustrate physical traffic calming measures that may be used in the City of San Leandro. For a variety of reasons, not all measures may be acceptable or desirable in all situations. Some measures are not acceptable for use on certain streets that may be primary emergency response routes as determined by the Fire Department. The Fire Department must approve the location and design of all traffic calming devices. The determination of which measures best suit each application will be worked out between the Engineering and Transportation Department, the Fire Department and the residents in the neighborhood. This toolbox is meant to be a flexible inventory of tools that may be updated as new and innovated traffic calming measures are discovered. There are a few devices that are commonly requested as traffic calming devices but are not allowable under this program. As few examples are as follows: Stop Signs: Stop signs are traffic control devices, not traffic calming devices. As such, their use is governed by the State that requires certain established criteria (warrants) to be met. Studies have shown that stop signs that do not meet established criteria have a higher violation rates which may increase collisions. Also, these studies show that vehicle speeds after the vehicle has passed through an unwarranted stop controlled intersection are as high, if not higher that without a stop sign, as motorists try to "make up" time lost. The acceleration and deceleration near stop signs generates noise and adversely effects air quality. A stop sign may be requested as part of a routine request for traffic control devices and they will be evaluated based on established criteria. Diverters and Street Closures: Diverters and street closures are measures that alter the existing transportation circulation system. In developing a solution for one neighborhood traffic problem, it is important not to shift the problem to another neighborhood. These devices can cause a tremendous amount of traffic diversion over a wide area. As such, their impacts would need to be evaluated in a greater scope than just within a particular neighborhood. The impacts would include the environmental impacts due to changing the transportation circulation system. Many other cities have policies that ban or discourage street closures. For these reasons, diverters and street closures are not recommended for use as traffic calming measures, but rather should be evaluated as part of a larger area-wide study if their use is to be considered. Rumble Strips: Rumble strips are a series of pavement bumps that create a "rumble" effect as cars drive over them. They are often used to alert drivers as they approach tolls on toll-ways or stop signs on highways in rural isolated areas. Rumble strips are not effective as speed control devices. In addition, due to the noise they generates as vehicles pass over them, their use is inappropriate within neighborhoods. Children at Play Signs: These signs are commonly requested in neighborhoods, however, they are no longer approved traffic control devices. They have not been found to be effective in improving the safety of children. Residential areas commonly have children and the presence of signs does not change driving behavior in the neighborhood. One of the disadvantages of these signs is that they can create a false sense of security amongst children and their parents which may increase the potential for accidents. If the safety of children is the major concern in a neighborhood, there are more effective tools that can be used to improve safety. City of San Leandro, Engineering and Transportation Page 9 of 23 4/20/06 NEIGHBORHOOD TRAFFIC CALMING PROGRAM