This outlines the procedures followed by the City of Rio Rancho’s Department of Public Works-Engineering Division-Traffic Section for requests made to install or provide traffic calming measures on a city street.
The Department of Public Works has developed a traffic calming program for the city. Any resident can request that their street be considered for a traffic calming solution. These solutions range from the installation of speed humps to various other measures such as traffic circles, bulb outs, semi-diverters and chicanes.
· Traffic circles are small circles placed in a four-way intersection. They force the driver to deviate around them, thus slowing the vehicle down.
· Bulb outs are a way of narrowing an approach to an intersection. They are used primarily to slow turning cars.
· Semi-diverters completely shut access to one direction of traffic. This can significantly reduce volume on a road.
· Chicanes are combinations of bulb-outs or medians that force vehicles into a circuitous path.
While many see speed humps as an easy way to deter speeding on their streets, they have limited effectiveness. As a result, there are not many streets in the city that would benefit from their placement. The use of stop signs as a speed deterrent is strictly prohibited by the Manual of Uniform Traffic Control Devices (MUTCD) and shall never be placed where not warranted.
Only residential streets can be considered for speed humps and traffic circles. In addition to slowing down normal traffic, these measures also increase emergency response time. Collectors, such as Western Hills, Leon Grande, Sandia Vista, and Pecos Loop are primary emergency routes, and any calming on these streets would adversely affect Fire Department (FD) response times to a large number of residences. Public Works has other measures, such as raised pavement markings, or “buttons,” as well as various striping configurations where speed humps and traffic circles are not allowed.
To qualify for traffic calming a street must have at least an 85th percentile speed of 32 mph, and around 1000 vehicles per day. The 85th percentile speed is the speed at which 15% of traffic exceeds. If speeds are any lower, then traffic calming may not be effective. Residential streets with traffic calming measures in place typically have an 85th percentile speed of 30 mph, so streets that already have an 85th percentile speed at or below 30 mph are not eligible for traffic calming.
In all cases, engineering judgment, particularly in regard to the volume requirement, is used to ensure that special cases receive due consideration. Circumstances under which a road might not meet minimum volume requirements may include, but are not limited to:
1. Speeds higher than the 32 mph requirement.
2. Percent of drivers exceeding 10 mph over the speed limit much higher than citywide average.
3. A road being used as a “cut-through” route, where volumes are substantially higher than the surrounding neighborhood would generate.
Residents should keep in mind that while traffic calming is effective at slowing the majority of traffic, certain drivers will still travel at excessive speeds in between calming measures and occasionally over or through them.
Once a request is received, Public Works will perform a study on the street. After the study is completed, the data is reviewed. If the initial results indicate that the street is a good candidate for traffic calming, then it is presented to the City Engineer and the Traffic Safety Advisory Committee (TSAC). TSAC is composed of representatives from Public Works Engineering, the Fire and Police Departments, Rio Rancho Public Schools, and the Development Services Department. If TSAC approves the recommended traffic calming plan, then Public Works will send a petition form to the resident that requested the study. That resident is then responsible for gathering signatures from all residents who live on the street where the calming measures are to be placed. Traffic Staff can help to coordinate this petition if needed. If at least a two-thirds majority desires the proposed traffic calming measures, Public Works will install them once budget has been identified. In some cases, a presentation at a Homeowner’s Association meeting may be a more appropriate venue for presenting the traffic calming plan. In that case, approval by the HOA is considered enough to proceed with construction.