Draft Traffic Calming Policy Paper What is Traffic Calming The term traffic calming is defined differently throughout the United States. The Institute of Transportation Engineers, an international educational and scientific association of transportation professionals, defines traffic calming as follows: Traffic calming is the combination of mainly physical measures that reduce the negative effects of motor vehicle use, alter driver behavior, and improve conditions for non-motorized street users (bicyclists, pedestrians, etc ). In an effort to improve safety for non-motorized street users and improve neighborhood livability, many cities in the Bay Area have expanded this definition to also include non-physical measures, such as education programs and enhanced enforcement. Introduction As traffic congestion increases in the Bay Area, many cities frequently receive complaints from their residents about speeding and cut-through traffic in their neighborhoods. In response to public concerns, many cities have adopted a traffic calming program, frequently referred to as the Neighborhood Traffic Management Plan, to systematically address public concerns. The City of Gilroy currently does not have an adopted traffic calming program. The purpose of this policy paper is to describe typical traffic calming approaches in other cities, and serve as the first step in developing a traffic calming policy in the City of Gilroy. This policy paper reviewed the current traffic calming plans in nine comparable cities within the Bay Area: City of Morgan Hill City of Sunnyvale City of Mountain View City of Palo Alto City of Menlo Park City of Redwood City City of San Mateo City of Fremont City of Livermore This policy paper found that most adopted traffic calming plans contain five sections: 1) traffic calming issues, 2) street qualifications, 3) appropriate traffic calming devices and implementation stages, 4) implementation procedures, and 5) funding and prioritization mechanisms. This paper first defines the various terminologies in this paper, then discusses each section of a typical traffic calming plan in detail and highlights the commonalities and differences between each city s adopted plan.
Definitions This section presents a brief definition and discussion about the terminologies used in this paper. 85 th Percentile Traffic The 85 th percentile speed is the speed that 15 percent of the vehicles on the roadway exceed. The 85 th percentile speed is important because it is used by traffic engineers to determine speed limits, which must be set at reasonable levels to achieve compliance. Average Daily Traffic (ADT) Average daily traffic (ADT) represents the total number of vehicles using the street on a typical day. Cut-Through Traffic Cut-through traffic refers to traffic that has neither an origin nor destination within the neighborhood. Neighborhood Neighborhood is a contiguous area bounded by arterials or natural boundaries. Roadway Classification Roadways within a City are typically classified in the City s General Plan. There are differences among cities in street classifications, but there is an overall theme that each City has arterials, collectors, and local streets. Arterials are the major thoroughfares within the City that connect City streets to the regional network. Local streets are roadways that provide access to individual properties and are mostly residential in nature. Collector streets serve as the connection between local streets and arterials. Traffic Calming Issues Many cities have clearly identified the issues that could be mitigated using the traffic calming plan. In most cities, speeding and high traffic volume (due to cut-through traffic) are the two primary traffic calming issues. Some cities, such as the City of Morgan Hill, have also included accidents and high truck volume as traffic calming issues. Many cities recognize that not all traffic related issues can be addressed with the traffic calming policy. The City of Fremont is unique because it identifies only speeding as a traffic calming issue. Street Qualifications Traffic calming measures are mostly designed to maintain a reasonable travel speed and/or regulate the volume on the affected streets. Therefore, traffic calming measures may not be applicable to all street types. Applying traffic calming measures on residential streets makes sense as these are the streets that should have lower speeds and volumes. Reducing arterial speeds and capacities may cause more vehicles to seek alternative cut-through routes on collector and residential streets, and would undermine the purpose of traffic calming. Collector streets are more challenging because these streets should be allowed to maintain an intermediate level of traffic volume (lower than arterials but higher than residential streets), so traffic calming measures should be used more carefully on these streets.
Research found that cities do not have a consensus on the types of streets qualified for traffic calming measures. Three cities restrict traffic calming measures exclusively to streets that are local and/or residential as classified in their general plans. Five cities allow some collectors that are residential in nature to qualify for traffic calming. The City of San Mateo is unique because it also allows certain non-aggressive traffic calming measures on arterial streets. In all cities, the qualified streets also have to pass a threshold test to be eligible for traffic calming measures. The 85 th percentile speed and average daily traffic (ADT) volume are two common criteria used to qualify streets for traffic calming measures, as discussed below: Speeding: Most cities within the Bay Area define a speeding issue within a residential neighborhood (25 mph speed limit) as having the 85 th percentile speed exceed 30 mph to 32 mph. Volume: Typical ADT thresholds range between 1,000 vehicles per day (vpd) to 2,000 vpd for residential/local streets, and between 3,000 vpd to 4,000 vpd for collector streets, if qualified. Some cities, like Sunnyvale and Mountain View, also require streets to meet a cut-through percentage threshold. The cut-through traffic threshold ranges between 25% to 40% of the ADT. For cities whose traffic calming plan is restricted to speeding and volume issues, the 85 th percentile speed, ADT and/or cut-through percentage are the only thresholds qualifying a street for traffic calming. Other cities, like Palo Alto and Morgan Hill, that have broader definitions of traffic calming issues have also included accident rates as a threshold. It should be noted that many physical traffic calming measures that are designed to slow vehicles or restrict vehicle access would have negative effects for emergency vehicles, buses, and/or trucks. All cities recognize these effects and most cities require these be considered when qualifying streets for traffic calming and/or analyzing traffic calming alternatives. The City of San Mateo has further spelled out in the plan that all designated primary response routes, bus routes, and truck routes are ineligible for physical traffic calming measures. Each City s qualification criteria for traffic calming is summarized on Table 1.
Table 1 Qualification Criteria Summary City Qualification Criteria General Plan Classification 85th Percentile Speed Volume Accidents * Morgan Hill "Local", "Collector" 32 mph "Local" ADT >2,000 vpd; "Collector" ADT > 3,500 vpd 5 in last 3 years Sunnyvale "Residential" 32 mph ADT > 1,000 vpd Mountain View Residential local and collector speed limit + 7mph cut-through > 25% ADT Palo Alto Residential local and collector "Local" > 32 mph; "Collector" > 35 mph "Local" ADT > 1,200 vpd; Collector ADT > 4,000 vpd 6 in last 3 years; Menlo Park (Level 2 projects) "Local", "Collector" speed limit + 7mph "Local" ADT > 1,500 vpd; Collector ADT > 3,000 vpd 3-yr accident rate > City average for comparable streets Redwood City "Local Street"; "Pedestrian Street"; or "Bicycle Boulevard" speed limit + 5mph cut-through > 40% ADT San Mateo Residential streets speed limit + 7mph ADT > 1,000 vpd; and cut-through > 25% ADT Fremont Residential streets 33 mph ADT > 3,500 vpd Livermore "Local", "Collector" 33 mph ADT > 1,000 vpd Notes: * Must be accidents preventable via traffic calming
Traffic Calming Measures & Implementation Stages Traffic calming measures can typically be divided into two categories: non-physical and physical measures. Common non-intrusive and potentially-intrusive measures are briefly discussed below and listed in Table 2: Non-intrusive measures include educational programs, police enforcement, additional signage (stop signs and turn-prohibition signs excluded), and additional pavement striping. These measures do not disturb normal traffic operations and target only those that are speeding and/or cutting-through. These measures are easy to implement, relatively inexpensive, less intrusive, and have few negative effects. At the same time, these measures are also less effective in mitigating the traffic calming issues. Potentially-intrusive measures typically include speed humps/tables, traffic circles/roundabouts, physical lane narrowing/shifting measures (i.e. bulbouts, chokers, chicanes), and physical movement-restriction measures (i.e. turn-prohibition, forced-turn channelization, half street closure and full street closure). Unlike non-intrusive measures, potentially-intrusive measures inconvenience all vehicles. Potentially-intrusive measures are difficult to implement, relatively expensive, can be very intrusive (i.e. full street closure), and have varying negative effects (i.e. visual and noise impacts, primary response times, diverted traffic). Examples of the potentially-intrusive measures are presented in Appendix A. Research found that there are mainly two ways cities approach traffic calming measures: caseby-case and staged. The case-by-case approach allows staff more options in evaluating each traffic calming case because the adopted traffic calming policies do not restrict the available traffic calming measures. The City of Palo Alto and City of Redwood City are the two cities that provide this flexibility. The other cities that were studied have defined stages of implementation of traffic calming measures. Stage 1 typically allows only the non-physical measures discussed above, and stage 2 measures encompass the physical measures. These cities require staff to consider Stage 2 measures only after determining Stage 1 measures are ineffective. Some cities, like Sunnyvale, do not restrict the available measures in Stage 2. Some cities, like Menlo Park, have clearly defined measures that staff can choose from in Stage 2. The City of Morgan Hill separates the movement-restriction measures from the rest of the physical measures and labels them as Stage 3 measures. The City of Fremont is unique because the ADT is used as a threshold to determine the implementable measures. Streets with ADT greater than 800 vpd but less than 3,500 vpd are allowed to implement only speed humps. Fremont has an adopted Speed Hump Policy that guides the process. Streets with ADT greater than 3,500 vpd are allowed to implement traffic calming measures from the City-approved list.
Table 2 Common Traffic Calming Measures/Devices Traffic Calming Measure/Device Non-Intrusive Measures Educational Programs Brief Discussion Meetings and workshops to educate residents about traffic safety issues Police Enforcement Signage Deploy polic officers to target neighborhood streets with reported speeding problems Speed limit signs, radar speed feedbacks, etc. Pavement Striping Lane striping to narrow travel lane widths usually to 10 feet wide Potentially-Intrusive Measures Speed Humps/Tables Traffic Circles/Roundabouts Bulbouts Raised areas placed across the road designed to slow vehicles as they approach the humps/tables Raised circular islands placed in the center of an intersection designed to slow vehicles and reduce intersection conflict points Curb extensions placed at an intersection to narrow the travel lanes Chokers Curb extensions placed along a roadway to narrow the travel lanes Chicanes Turn-Prohibition Alternating curb extensions placed along a roadway to narrow the travel lanes and create an "S-shaped" street Signage restricting specified turn movements at an intersection Forced-Turn Channelization Raised islands at an intersection that block certain movements Half-Street Closure Full-Street Closure Physical barriers placed at one end of an approach so the street can only be entered from one direction but vehicles can exit in both directions Physical barriers placed at one end of the street effectively creating a dead-end Typical Implementation Procedures While each city follows a unique implementation procedure, research found that all cities procedures follow some variation of the following pattern: 1) resident-initiated request, 2) request qualification, 3) neighborhood meetings and traffic calming studies, 4) neighborhood consensus, 5) traffic calming measure approval, and 6) implementation. Each step of the procedure is discussed below in detail and summarized on Table 3. Sample implementation flow charts from the researched cities are included in the Appendix. Request Initiation Most cities require the traffic calming process to be initiated only by a resident request. Morgan Hill allows staff to initiate the process if staff has the perception that a traffic calming issue exists. Upon receiving the resident request for traffic calming, and deeming that the concerned street is a suitable street for traffic calming based on street classification, approximately half of the researched cities would continue to the next step: request qualification (discussed below). The remaining cities would request the resident submit a petition form indicating that the expressed concern is widespread and shared. Staff would determine a project area that could vary from the block of concern to a few blocks that could be affected by potential traffic calming measures. The required signatures collected vary from 10% to 60% of the study area. In cities where an initial petition is required, the traffic calming process will continue only if the concern is considered widespread and shared via the petition.
Prior to qualifying the request, four cities (Redwood City, Morgan Hill, Mountain View, and San Mateo) require Public Works staff to review the signage and striping of the concerned street. If determined by staff that either additional signage (i.e. speed warning signs) and striping could mitigate the expressed concern, then such measures are implemented and it is deemed that the concern has been addressed. The City of Morgan Hill in addition requires staff to hold an initial neighborhood meeting to gauge the concerns before qualifying the request/concerns. Request Qualification After the request initiation, based on the specific concern (i.e. cut-through traffic, speeding), staff would collect data on the concerned street and determine whether the street meets the criteria (85 th percentile speed, ADT, or percent cut-through) for traffic calming. The process is continued if the request is qualified. For the City of San Mateo, data are collected as part of a follow-up study 3 months after Step 1 measures have been implemented. For the cities that do not require neighborhood petitions prior to data collection, most of them require a neighborhood petition with 50%-60% support after qualifying the request. Neighborhood Meetings and Traffic Calming Studies All cities share a common philosophy that traffic calming projects are for the residents, and neighborhood involvement is critical in each step of the traffic calming procedure. Research shows that once the resident request is qualified for traffic calming, all cities then begin the process of hosting neighborhood meetings and developing traffic calming studies. The neighborhood process all entailed at least two meetings: one initial meeting to explain the traffic calming process and a second meeting to discuss the potential traffic calming measures. Many cities also ask the residents to form a steering committee after the initial neighborhood meeting to represent the neighborhood and interact with staff. While all cities involve residents in the study process by hosting neighborhood meetings, there are various levels of resident involvement in determining the traffic calming plans: 1) staff lead the process, 2) residents lead the process, and 3) resident/staff share the lead. These distinctions are discussed below: The City of San Mateo is the only researched city that requests residents take the lead in developing the traffic calming plans. City staff s role is limited to periodically reviewing the plans and providing support in the process. Staff review is to ensure that the proposed plan is in line with the city adopted policies and that no considerable impacts (i.e. diverted traffic, primary response times, drainage) would occur as a result of the proposed plan. In Sunnyvale, Menlo Park, Livermore, and Redwood City, City staff would lead the process in developing the traffic calming plans. This is not saying that residents are not involved in the process, it just means that the process of developing a traffic calming plan is led by City staff. After qualifying the resident requests, City staff would develop the initial traffic calming plans with alternatives. Neighborhood meetings then occur so staff could explain the various alternatives and hear feedback from residents. Staff would then revise the plans based on resident feedback and hold additional meetings so residents could reach a consensus on the identified traffic calming plan. During the initial development of traffic calming plans, City staff would have considered the potential negative impacts of the plan, and consulted other relevant departments to ensure city policies are upheld with the plan.
The remaining cities require staff and residents to work together to develop a desired traffic calming plan during the neighborhood meetings. Palo Alto and Fremont specify that the residents should select a working group to work with city staff to develop the plans. The other cities do not specify the need for a working group. Neighborhood Consensus Once the traffic calming plan is identified and supported by both the staff and neighbors during the neighborhood meetings, most cities then require a neighborhood vote to put the plan before city decision bodies (i.e. traffic commission, city council) for approval. The voting area and level of required support to advance the plan differ among cities. The required support level within the voting area ranges between 50% and 70%. For some cities, the neighborhood voting area is the same as the study area. Other cities restrict the voting area to only the affected blocks, which may be smaller than the initial petition area to start the traffic calming process. The City of Morgan Hill further requires that all owners with properties directly fronting the installation must approve the plan for the plan to advance. The City of Livermore is unique because once a traffic calming plan is finalized during the neighborhood meetings, staff will install temporary devices to serve as a trial installation of the traffic calming measures. At the end of the trial implementation period (length not specified), staff will prepare a follow-up study, and present findings to the neighborhood. The neighborhood is then asked to vote on the permanent implementation with a required 60% support to advance the plan for city council approval. Traffic Calming Plan Approval The traffic calming plan that has been developed by the neighborhood and city staff and reviewed by other City departments is then submitted to the city decision bodies for approval. Half of the cities require only the City Council to hear the plan. San Mateo requires the Public Works Commission to review the plan prior to City Council. Palo Alto and Menlo Park require the Planning/Transportation Commission to review the plan prior to City Council. Implementation For half of the researched cities, once the appropriate decision bodies (discussed above) approve the plan, city staff would permanently implement the traffic calming measures. A trial implementation is not needed, except in the City of Livermore where a trial implementation is required prior to neighborhood approval of the plan. The City of Fremont requires a follow-up study to evaluate the effectiveness of the traffic calming measures. In the other half of the researched cities, a trial implementation of the traffic calming measures is required. All of these cities require staff to conduct a follow-up study 3 months to a year after the trial implementation. The follow-up study would ensure the implemented traffic calming measure is effective in mitigating the expressed concern and would ensure that no unintended impacts are generated. In Morgan Hill, if staff determines that the implemented trial measures are effective, permanent measures will be implemented. Staff do not need to consult the neighborhood. In Mountain View, staff have the option to recommend the permanent implementation to Transportation Commission and/or City Council without neighborhood review. In Palo Alto and Menlo Park, staff present the follow-up study results to the neighbors in another neighborhood meeting. Neighbors are then asked to vote on the final implementation. If a simple majority is achieved, the final implementation plan is brought forward for Transportation Commission and/or City Council approvals. The approved final plans will then be permanently implemented.
See Table 1 Table 3 Summary of Each City s Traffic Calming Procedure City Process Initiation Immediate Staff Action Qualification Allowed? Criteria Plan Development Required Support Test Period Funding Prioritization Morgan Hill Citizen Request or staff Yes Staff and neighbors 60% * 6 months CIP/Citizens Priority List * Sunnyvale Citizen Request No Staff 60% * None General Fund First come first serve Mountain View Citizen Request Yes Staff and neighbors 67% 1 year CIP First come first serve Palo Alto Citizen Request No Resident committee 50% None General Fund/Citizens Priority List Menlo Park (Level 2 projects) Citizen Request No Staff 50% Yes, unspecified General Fund length Priority List Redwood City Citizen Request Yes Staff 50% None General Fund Priority List San Mateo Citizen Request Yes Resident Committee 50% None Traffic Impact Fee First come first serve Fremont Citizen Request No Resident Committee 70% None General Fund Priority List Livermore Citizen Request No Staff 60% None Citizens Priority List Notes: Funding * 100% of fronting propoerties * considers level of citizen funding Most researched cities provide funding for the traffic calming program. The City of Mountain View specifies that funding will come from the general fund and for larger projects from the Capital Improvement Program. San Mateo specifies that funding will come exclusively from the Traffic Mitigation account, which is funded by an impact fee on new development. Three of the researched cities will accept/request outside funding. Morgan Hill funds projects through the Capital Improvement Plan but will also accept voluntary contributions. The City of Palo Alto dedicates $100,000 annually to fund traffic calming projects and will also accept voluntary contributions. For both Morgan Hill and Palo Alto, the voluntary contribution from residents would not affect the traffic calming planning and approval process. The contributions may be used only to speed up the construction process. The City of Livermore specifies that the City will cover full administration costs and will share the construction cost with the residents based on a scale system. Maintenance of the project is funded entirely by the residents.
Prioritization All researched cities recognize that they have only limited staff resources and budgets that can be devoted to traffic calming projects. Therefore, all researched cities have specified a prioritization method for the traffic calming requests. There are generally two methods of prioritization: 1) first-come first-served, and 2) scale system. Both are discussed below: San Mateo, Mountain View, and Sunnyvale are the three cities that work on traffic calming projects on a first-come first-served basis. Morgan Hill and Fremont specify that traffic calming projects will be taken by staff on a first-come first-served basis. Upon City approval of the implementation of the traffic calming measures, the projects will then be placed on a priority list based on a scale system. Priority is given to projects with the more severe traffic calming issues. In Morgan Hill, where the City accepts resident contributions, priority could be given to projects that are mostly funded by residents. The remaining researched cities will prioritize working on traffic calming projects based on a scale system after collecting sufficient data to qualify the projects. Priority is given to projects with more severe traffic calming issues. Device Removal The entire traffic calming process is designed to ensure community buy-in for the permanent installation of the traffic calming devices. However, it is possible that residents may later request the removal of the traffic calming devices. Three cities have not specified a process for device removals. Four cities have specified that only residents within the study area could later petition to remove the devices. The process to remove the device would be similar to the installation process with neighborhood meetings, neighborhood approval and city approvals. Mountain View and Morgan Hill also specify that if the follow-up study finds the devices to be ineffective, staff could recommend the removal of the devices and/or implementation of additional devices. While most cities have not specified the funding responsibility for device removals, San Mateo and Livermore require the neighborhood to fully fund the removal cost.
Traffic Calming Paper Appendix
Appendix A Traffic Calming Devices
Speed Humps Bulbouts Chokers
Chicane Traffic Circle
Roundabout Median Barrier
Forced Turn Half Street Closure
Full Street Closure
Appendix B Traffic Calming Implementation Flow Chart - City of Sunnyvale
Appendix 1 Traffic Calming Flow Chart 23 Appendix 1 Traffic Calming Flow Chart Traffic Calming Flow Chart Report the concern. Complete Traffic Calming Request Form. Is the location eligible for Traffic Calming? YES NO City Staff will work with residents to identify other actions. Study complete. Continue Traffic Calming Study. Traffic Calming deemed inappropriate. or NO NO NO NO NO Is there neighborhood consensus? Staff data collection and evaluation. Are thresholds exceeded? YES YES Stage 1 Traffic Calming implementation. YES Follow up data collection. Are thresholds still exceeded? YES Stage 2 Traffic Calming Study. YES Is there neighborhood consensus? YES City Council approval. YES Implementation.
Appendix C Traffic Calming Implementation Flow Chart - City of Fremont
Residential Traffic Calming Program Flow Chart Citizen Request Speed & Volume Study No speeding problem if 85 th percentile < 33 mph. No further actions. Education & Enforcement 3 Month Review Monitor for long-term effects, periodic education & enforcement. Effective RESULTS If speeding problem persists and ADT between 800 and 3,500 VPD If speeding problem persists and ADT > 3,500 VPD S1 City Speed Lump Policy Applies T1 Consider installation of alternative traffic calming devices. S2 Conduct speed lump warrant analysis. T2 Petition from 70% of affected residents living on the street. S3 Petition required from at least 70% of affected residents including consent from residents whose properties are adjacent to the speed lump. S4 Priority list established for all candidate street segments. T4 T3 Hold 1 st neighborhood meeting within six weeks after petition received. Informational meeting with potentially impacted residents. Select Citizen Committee. Meeting with Citizen Committee using interest based approach. Define problem & develop solutions & alternate plans. Staff to work with Committee & neighborhood residents (3 months). S5 Annual report prepared to City Council for approval and funding of top ranked street segments. T5 2 nd Neighborhood Meeting. Staff and Citizen Committee to present conceptual plans; receive neighborhood input (1-2 month). S6 Upon City Council approval, plans & specifications are prepared and project put out to bid. T6 3 rd Neighborhood Meeting (if needed). Staff to present final plans, work to obtain neighborhood consensus (1 month). S7 Installation of speed lumps. T7 Conduct post card survey of proposed measures. Need 70% of residents living on the street. Establish priority list (1 month). T8 Upon Council approval, install traffic calming devices with landscaping. T9 9 Month Review T10 Meets objectives. T11 Does not meet objectives. Note: Total planning process is 11 months. Planning schedule may be shortened dependent on scope of project and if neighborhood consensus is achieved early in the planning process. T12 Go back to City Council. Residential Traffic Calming Program April 2002 Page 4
Appendix D Traffic Calming Implementation Flow Chart - City of Morgan Hill
Appendix E Traffic Calming Implementation Flow Chart - City of Redwood City
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Appendix F Traffic Calming Implementation Flow Chart - City of San Mateo
FIGURE 6 Traffic Calming Procedure Initial Request Implementation of Step 1 Improvements Problem Abated No Step 2 Thresholds Met? Yes Petition Process Traffic Calming Plan Reviewed by Public Works Commission Initial Neighborhood Meeting Approved? No No Further Action Steering Committee Develops/Revises Traffic Calming Plan No Yes Traffic Calming Plan Reviewed by City Council for Funding Yes Traffic Calming Plan Reviewed by City Departments Approved? Department Comments? No Yes Construct Traffic Calming Improvements Neighborhood Meeting to Present Traffic Calming Program Problem Abated Support for Program Measured via Neighborhood Survey City of San Mateo Neighborhood Traffic Calming Policy 31