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HomeMy WebLinkAboutTrans 2008-03-25 Item 2A - Presentation - Tukwila's Traffic Calming ProgramTo: From: Date: Subject: ISSUE Presentation of the City's Traffic Calming Program. BACKGROUND Over the past several years, the City has received numerous requests for traffic calming treatments on local streets throughout the City. In order to address these neighborhood concerns, staff was directed to develop and begin implementing a Traffic Calming Program. After much research into traffic calming throughout North America, a Tukwila Traffic Calming Program was presented to the Transportation Committee in June 2005. This program was customized to meet Tukwila's needs for a user friendly, flexible program but one that also provided structure, guidance, and thresholds to ensure that limited funds and staffing were appropriately utilized. As part of the program development, one neighborhood agreed to participate as the city's pilot project: the area surrounding 37`h Avenue S and S 130 Street. A traffic committee was formed after staff met with the local residents and some data collection was done. Due to limited resources, and the opportunity to resolve much of the neighborhood concerns with the TIB Phase II project, no additional traffic calming measures were explored beyond the closure of the 37 Avenue S /TIB intersection. ANALYSIS Mayor Haggerton Public Works Director_Q March 25, 2008 Traffic Calming Initiating a Request Preliminary Evaluation Criteria Solution Alternatives Qualifying Requests INFORMATION MEMO Tukwila has a very good traffic calming program in place and staff will go through the program with the Transportation Committee. Attached to this Information Memo is the Traffic Calming Program (Attachment A) as well as the research report, Traffic Calming: Research into Select North American Traffic Calming Programs (Attachment B). A matrix and description of traffic calming measures analyzing effectiveness, advantages and disadvantages, potential impacts, and relative implementation and operation costs is also attached (Attachment C). Discussion will center around the Tukwila Traffic Calming Program. Plan Development Funding Design and Construction Evaluation Removal i \pubworks \cyndy \traffic calming \information memo traffic calming presentation 3 -25 -08 changes.doc At this time, staff has 21 requests for traffic calming They are as follows: Traffic Ca WO* Request =Laca ii Petition from residents 37`" Ave S and S 130 St Cascade View neighborhood 37 Ave S between S 135`" St and S 140 S Cascade View neighborhood intersection of S 144`" St and 37` Ave S Foster Park neighborhood 53`° Ave S between S 137 St and S 144 St S 160 St and 51 Ave S Crestview neighborhood S 160 St 42 Ave S 1200 block of S 58 St S 150 Place 42II Ave S from top of hill to S 154' St S 144 St between 56" Ave S and 58 Ave S S 128 St between E Marginal Way and Macadam 48 Place South and 144th St. 125th St and 50 Place South 34th Ave S/S 137th Street S 160th St between 46th and 48th 33rd Ave S between S 140th St S 144th St Cascade View Elementary: Solar Powered Stop Signs at 135th/32nd 144th/33rd 140th/37th and 133rd/Military: Solar Powered Stop Signs S 141st at 34th P1. S: request for chicanes :1/25/08 Military Rd between S 152' S 150 Street (SeaTac jurisdiction) S 150th Street between TIB 42h° Ave S ACTION Date Primary Received Complaint Speeding Cut through ;12/12/04 ;7/16/04 15/20/04 ;9/17/04 112/21/04 ;1/3/06 11/6/06 =1/18/08 11/18/08 is \pubworks \cyndy \traffic calming \information memo traffic calming presentation 3 25 08 changes.doc Speeding Speeding (Solar stop sign request !Solar stop sign ;request =Speeding Pedestrian 'Crossing !Pedestrian ,Safety Staff will investigate each request and provide a cursory review against the criteria and report back to the Transportation Committee with the priorities. Attachments: Attachment A Traffic Calming Program Attachment B Traffic Calming: Research into Select North American Traffic Calming Programs Attachment C Traffic Calming Methods Matrix and Descriptions Traffic Calming Program Attachment A Table of Contents INTRODUCTION 3 OBJECTIVES 3 PROCESS STEPS 3 INITIATING A REQUEST 3 PRELLMINARY EVALUATION 4 CRITERIA 4 SOLUTION ALTERNATIVES 4 No Action 4 Level I 4 Level ....5 PROCESS FOR QUALIFYING REQUESTS 5 PLAN DEVELOPMENT 6 PROJECT FUNDING 7 PROJECT DESIGN AND CONSTRUCTION 7 EVALUATION 7 REMOVAL 7 APPENDICES 8 APPENDIX A: DEFINITIONS OF TYPES OF STREETS 8 APPENDIX B: LEVEL I TREATMENT 9 APPENDIX C: PRIORITY POR■IT WORKSHEET 1. 10 Introduction Traffic conditions on residential streets greatly affect neighborhood livability. Speeding and unnecessary through traffic in neighborhoods create safety hazards on residential streets. The City of Tukwila has developed a Neighborhood Traffic Calming Program (NTCP) to guide City staff and inform residents about the procedures for implementing traffic calming on residential streets and collector streets. As defined by the Institute of Transportation Engineers (ITE), traffic calming is the application of measures which can be taken which reduce the negative effects of motor vehicle use, alter driver behavior and improve conditions for non motorized street users. The City's NTCP outlines a process for staff and residents to carry out a traffic calming program. It shows how to establish procedures with which to prioritize traffic calming requests. These procedures incorporate prioritization, planning, evaluation, implementation, and maintenance of the traffic calming devices in residential areas. Also, it combines the four E's Education, Engineering, Enforcement and Emergency Services. Objectives The primary goal of the City's NTCP is to improve the livability of the local streets and residential collectors. With this in mind, the City has identified the following objectives: Provide alternative solutions to reduce vehicular speeds and accidents on residential streets. Endorse safe and pleasant conditions for motorists, bicyclists, pedestrians, and residents of neighborhood streets Provide a means for a collaborative working relationship between City staff and neighborhood residents in development of traffic calming measures. Discourage use of residential streets for cut through vehicular traffic. Process Stens Initiating a Request Request for traffic calming assistance can come from a citizen's association or from concerned individuals. Requests can be made by letter clearly stating the problem and location, accompanied with completed application which is provided by the City. The request can be made by either mailing or emailing the request to the Public Works Department. The request must include a contact person. Staff will then acknowledge the completed application in writing to the citizen's association or to the contact person listed in the application. An application fee could be implemented in the future to offset some of the costs involved. Preliminary Evaluation In order to ensure that traffic calming concerns are addressed in an equitable manner, staff assess the situation by reviewing the request and determining if the area qualifies for treatment using set criteria. The primary purpose of a preliminary evaluation is to determine whether the speeding or accident situation is significant enough to warrant further study. At this stage, staff collect data and analyze it to determine whether: Roadway is eligible for traffic calming treatment. City recorded data supports the problem identified in the application. Criteria Each street in the community is a part of the larger roadway network that connects residents to each other, work, schools, goods, services and the countless destinations to which drivers and pedestrians travel daily. Common issues within neighborhoods include speeding, traffic volumes, and the utilization of neighborhood streets as a cut through route, among others. Qualification criteria for the NTCP assistance for local streets, and residential collectors (for definition of local street and residential collectors see Appendix A) are as follows: Speeding: the speeding criteria is met if 15% of the motorists travel at l0mph or more above the posted speed limit. Volume: the traffic volume criteria is met if the volume for the Local Streets are less than 3000 vehicles per day and Residential Collectors are less than 7,000 vehicles per day Traffic Accidents: the number of accidents for Local Streets and Residential Collectors is three or more in one year. If the analysis confirms that traffic problem exists based upon the above criteria, the Public Works Department will conduct a traffic calming study as explained in the following sections. Solution Alternatives The solution alternatives are defined into three levels. No Action If the request for a roadway are is judged to be not significant, the city staff will inform the applicant by letter that their request does not meet the city criteria for action. Level I First step to the improvement of traffic calming is some type of passive traffic control of Level I measures. Level I uses less restrictive measures, and does not require a neighborhood vote. The improvements used in Level I include: trimming bushes to allow better sight distance; pavement markings; police enforcement; traffic speed display signs; neighborhood awareness campaigns; and education (for list of potential Level I improvements see Appendix B). This reduces the need for installing physical devices on every local street. Level II Level II improvements should be considered if the Level I treatments do not resolve the problem. Level II improvements focus on physical devices such as speed humps, traffic circles, and chicanes (for a comprehensive list of devices see Appendix C) to calm traffic. These solution alternatives are much more costly than Level I and generally permanent. Therefore, a more detailed evaluation is required and approval by key departments and impacted area residents is required before the implementation. The detailed evaluation includes as follows: The speed, volume and accident history collected during the preliminary evaluation. Additional speed and volume, which may be collected after Level I implementation. (Data collection should be conducted on weekdays, September through May, when public school is in session.) Other factors such as proximity to schools, parks and other pedestrian destinations, lack of sidewalks, accessibility and special needs issues, bicycle accessibility, roadway characteristics. Process for Qualifying Requests If a traffic problem, as defined in Criteria section, does exist, then the staff establishes an impact area, collects additional data and calculates the priority score for the street segment using the Priority Worksheet (see Appendix C). To determine the score staff will: Collect any accident history for three consecutive years, traffic speed and/or traffic volume data available. If no count information is available, data will be collected. Identify users of the affected streets. Identify traffic generators, such as schools, parks and shopping centers. Analyze street use with respect to street classification. Document any other relative factors. The applications are then prioritized based on the scores. Accordingly, the highest ranking request should be undertaken during the coming year, depending on the budget. Plan Development Once an area has been selected for a traffic- calming project, steps need to be taken to determine solutions. Since Level 1 solutions are simpler in scope, the solution formulation process can usually be handled within the engineering department. Public meetings are not usually required, although some type of public communication is beneficial and recommended. Level II improvements require a more comprehensive plan development due to the cost and high impact of the actions taken. A public meeting with all affected property owners is required. The initial public meeting will: Discuss the steps to develop a traffic calming plan. Gather additional information regarding traffic problems and related neighborhood needs. Form a citizen traffic committee. The committee should consist of about four to six residents and will work with the city staff during this stage. The neighborhood committee should be representative of the entire impacted area rather than concentrated on one or two streets or areas. Once the committee is formed, it will function as the liaison between the city and neighborhood residents. The city staff will work closely with the neighborhood committee to identify the petition area and to find a traffic-calming measure that most realistically addresses the traffic concerns. The committee will inform the residents of the traffic calming process and will assists in obtaining the required number of signatures needed. The next step in the implementation process is that the staff must determine if the project has sufficient neighborhood support to warrant funding. A ballot is sent to each property owner in the impacted area where they are asked to vote on the issue. The implementation must receive at least 65% approval of all residents in the impacted area in order to proceed. In addition to the community support, the approval of the following public officials is required: City Police and Fire Departments Neighborhood Traffic Committee City Council Once the necessary level of support is determined, projects will be funded according to their prioritization. In cases where a request does not receive sufficient support, the project is dropped from the list and the next highest ranked project can go through the same process. Residents in an area where a project has been dropped are able to resubmit their request for the following program year. Project Funding Once a solution has been determined and approved, the project will go through the process of approval for funding. All traffic calming projects are fully funded by the City. The number of traffic- calming projects undertaken each year depends on a City's budget. In some cases, landscaping, maintenance and necessary easement dedication can be the responsibility of the residents or the homeowners associations. If this is the selected choice, an agreement must be signed between the City and residents before the project is implemented. Project Design and Construction Once traffic- calming treatments have been agreed upon and approved, the City's staff or a consultant develops the detailed plan, based on the study and the residents' input. The traffic calming device will be installed as soon as possible. In some situation, a test installation might be warranted to assure that the device is both effective and truly desired by the community. In this case, within three to twelve months after installation, staff evaluates how well the test installation performed in terms of the defined problems and a poll is taken of all the affected residents to ensure continued support. Evaluation An evaluation shall be conducted between six months to one year after the construction of the permanent traffic calming device. Speed, volume and collision data is collected and compared with the data collected before the installation of the traffic calming device. The data collection should be done at approximately the same time of year as the original data collection. Removal If the impacted neighborhood is dissatisfied with the outcome of the implementation, they can submit a petition to modify or remove the traffic calming device. The petition must be signed by over 70% of the residents within the impacted area. If the residents vote to remove the traffic calming device then the residents must pay the cost of removal and fixing the road way to the City's standard. If the staff determine that the traffic calming devices have resulted in an unacceptable safety issue, the removal of the devices will be done at the City's cost. Ap pendices Appendix A: Definitions of types of streets Local streets (typical speed limit 25 mph) serve local circulation needs for motor vehicles, bicycles, and pedestrian traffic and provide access to residences and some businesses. Local streets are not intended to carry significant volumes of through traffic. Residential collectors (typical speed limit 30 -35 mph) are somewhat more difficult to define. Collector streets are typically streets that provide access between local service streets or from local streets to thorough fares. Residential collectors often carry some through traffic. Appendix B: Level I Possible Treatments Educating the Community Educating the community on traffic issues is an important first step in addressing the residents' concerns. Most of the time, the residents do not acknowledge that the majority of people who speed in neighborhood streets are the local residents; therefore, educating them about speeding and their driving behaviors can improve driving habits. Neighborhood Awareness Campaign In the neighborhood awareness campaign, residents should be given partnership in solving speeding problem in their neighborhood. This is done by allowing residents to go out in their local streets, using radar equipment, and monitor speeding vehicles. Residents should be trained to use the radar equipment and should be given instruction in collecting data. These volunteers should record license numbers of the speeding vehicles. The violators (vehicles registered owner) will receive a letter from the City, informing the owner of the observed violation and encourage them or drivers of their vehicles to drive at or below the posted speed limit. However, no formal violations or fines are issued. Pavement Markings, Speeding Limit Signs and Vegetation Trimming Improvement can be made by simply marking the pavement, installing speed limit signs at more visible locations, or trimming bushes for a better visibility; this will allow drivers to be aware of the speed limit of the local streets. Pavement marking and signing include signs for residential zone designation, speed limit and other necessary information needed for motorists. Police Enforcement The traffic enforcement encourage drivers to change their driving behaviors through giving citation to violators. The Police Department should be given the information of the data collected of the location. This information helps the officer to determine the time of day of the speeding mostly occurs. Radar Speed Trailer Deployment Use of a Radar Speed Trailer to heighten the drivers' awareness of the speed they are traveling is also useful in driver education. Sometimes deploying the Radar Speed Trailer will result in allowing the concerned neighborhood to see that actual speeds may not be as high as what had been perceived. Appendix C: Priority Point Worksheet. Location: Date: Staff Name: Category 1. Accidents: 1pts for each recorded accident of the roadway for the past 3years 2. Volume: Average daily traffic volumes (weekday) divided by 100 3. Speed: 5pts for every mph more than 5 -1 Omph above the posted speed limit 4. Sidewalks: If sidewalks exist Opts; if not 5pts 5. School: l Opts for each school within the impacted area Speed. Accident and Volume Data Volume 85% Speed l0mph above Total Points: Points I Basis for Point Assignment Chart Criteria 1 Basis for Point Assignment Accidents 10 points for each recorded accident of roadway for the past three years total (5 points will be added if there an injury reported) Speed 5 points for every mph greater thanl0mph above the posted speed or [(85th percentile speed limit 10 mph posted speed limit) x 5 points] Volume 1 point for every 200 vehicles (Residential) Average daily traffic volumes (weekday) Volume 1 point for every 500 vehicles (Collector) Average daily traffic volumes (weekday) Sidewalks 5 points if there is not a continuous sidewalk on one side of residential streets or both sides of collectors Schools 5 points for every school within the impact area and 2 points for school property within 500 ft of the impact area CITY OF TUKWILA PUBLIC WORKS DEPARTMENT TRAFFIC CALMING: Research into Select North American Traffic Calming Programs June 2005 Research Conducted By Sara Haile Report by Sara Haile and Cyndy Knighton ATTACHMENT B TABLE OF CONTENTS Introduction 4 The Traffic Calming Approach 4 Level I 5 Level II 5 Level III 5 Implementation Process 5 Initiating a Request 5 Preliminary Evaluation 6 Local Street 6 Residential Collectors 6 No Action 7 Level I 8 Level II 8 Traffic Speed 8 Traffic Volume 8 Accident History 9 Plan Development 10 Final Ballot 10 Final Design 11 Project Funding 11 Construction 12 Evaluation 12 Removal and/or Modification of Treatments 12 Level III 13 Information on Sample Data Set 13 Additional Information 15 Summary 15 Appendix A Priority Ranking Criteria Sample 16 TABLE OF TABLES Table 1: Street Classification Criteria 7 Table 2: Traffic Volume Criteria 9 Table 3: Funding Solutions 11 Table 4 Jurisdiction Profile 14 Introduction One of the City of Tukwila's priorities has long been to protect and strengthen the quality of life in its residential neighborhoods. Traffic conditions on residential streets greatly affect neighborhood livability. Speeding and unnecessary through traffic in neighborhoods create potential safety hazards on residential streets, an issue which led the City to develop a traffic calming program. The purpose of the traffic calming program is to guide City staff and inform residents about the procedures for implementing traffic calming on residential streets. In order to assist the City of Tukwila in developing an effective traffic calming program, this report assesses traffic calming programs in different jurisdictions throughout the United States as well as the Canadian Guide to Neighborhood Traffic Calming Handbook. The following jurisdictions were studied for this report: Alexandria, VA Asheville, NC Bellevue, WA Bloomington, IL Bothell, WA Chattanooga, TN Overland Park, KC The Traffic Calming Approach Portland, OR Roswell, GA Sandy, OR Sandusky, OH Sebastopol, CA Seattle, WA Snohomish County, WA In general, it is essential for a jurisdiction to maintain a system of local access neighborhood roads as well as arterial roads that allow people to travel from their neighborhoods to places of employment, recreation, schooling, and shopping. Traffic calming programs should encourage through -traffic to use arterial roads and not simply divert traffic from one local access road to another. However, achieving this requires careful planning. Traffic calming is defined by the Institute for Transportation Engineers (ITE) as "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." A traffic- calming program implements a process for staff and residents to follow, as well as establishes criteria with which to prioritize requests. The intent of a traffic calming program is to enable individual citizens and/or community groups to participate in problem identification, planning, designing, implementing, and evaluating stages of the traffic- calming process while working jointly with City staff towards a solution. Community involvement allows staff to learn about the residents' perception of problems, the extent of their concern and needs, and to evaluate solutions on the basis of interaction with local residents. An effective traffic- calming program requires a carefully designed process of implementation, based on explicit guidelines, policies, and procedures. These procedures cover prioritization, planning, evaluation, implementation, and maintenance of the traffic- calming devices in residential areas. An effective traffic- calming program combines all of the four E's Education, Engineering, Enforcement and Emergency Services. Analysis of the various traffic calming programs studied for this report revealed similar goals for each jurisdiction. However, the processes and treatment used to achieve these goals varied from jurisdiction to jurisdiction. The study found that traffic calming programs typically provide three distinct levels of response. Level I. In general, Level I uses less restrictive measures, which rarely require a neighborhood vote. The improvements used in Level I include: trimming brushes to allow better sight distance; pavement markings; police enforcement; traffic speed display signs; neighborhood awareness campaigns; and education. This reduces the need for installing physical devices on every local street and allows residents the opportunity to play an active role in addressing the situation in their neighborhood. Level II. Level II improvements focus on physical devices to calm traffic, such as speed humps or traffic circles, (for list of devices see Appendix B of Toolbox). Level II improvements may be used if the Level 1 treatments, which usually take three months to one year to take effect, do not resolve the problem. Level II calming may be considered, depending on priorities and available funding. Level III. Level III uses the same calming devices used in Level II responses; however, Level III is usually applied during larger -scale neighborhood projects or when the neighborhood problem is determined to be caused by lack of adequate arterial facilities and sidewalks in the problem area. The City of Portland has a unique, project type approach. Instead of defining different Levels of improvement the city classifies the types of projects as: Local Streets in a neighborhood (similar to Level II) Neighborhood Area Studies, which respond to more than one local street in a neighborhood. In the City of Portland, neighborhood Area Studies generally take longer to complete than Local Street improvement projects due to more research and analysis, and a greater amount of required neighborhood involvement. Initiating a Reauest IMPLEMENTATION PROCESS To initiate a request for traffic calming, typically, some entity from the community, either an individual or a homeowners association, contacts the jurisdiction for assistance. With one exception, all jurisdictions begin an analysis based on a request from a single individual. For the majority of the jurisdictions analyzed for this report, requests are made by letter, phone or email. One jurisdiction, the City of Alexandria, has an on -line application form that must be filled out and accompanied with a letter identifying the problem in detail. The request must identify a neighborhood contact or representative person. Some jurisdictions may also initiate requests as a result of ongoing monitoring efforts by Public Works staff. Listed below are processes and requirements highlighting variations used by different jurisdictions. City of Alexandria: if there is no active neighborhood association, the application must include the signatures of at least five affected homeowners, not all from the same street. This requirement is to ensure that the problem is perceived as neighborhood -wide and is not solely an individual problem. City of Asheville: after receiving a request, questionnaires are sent to the residents asking for additional information about the problem areas. City of Sandy: the application must be accompanied by a petition with signatures of at least 50% of the residents along the affected street. City of Sebastopol: an application fee of $100.00 for initial evaluation is required. Preliminary Evaluation Traffic calming program usually addresses local streets and residential collectors which are defined as follows. a. Local streets (typical speed limit 25 mph) serve local circulation needs for motor vehicles, bicycles, and pedestrian traffic and provide access to residences and some businesses. Local streets are not intended to carry significant volumes of through traffic. b. Residential collectors (typical speed limit 30 mph) are somewhat more difficult to define. Collector streets are typically streets that provide access between local service streets or from local streets to thorough fares. Residential collectors often carry some through traffic. These street definitions in some cases differ from one jurisdiction to another. Some jurisdictions, such as Bloomington, IL and Chattanooga, TN, do not consider collector streets for traffic calming treatment. See below in Table 1. As a result, in order to ensure that traffic calming concerns are addressed in an equitable manner, an appropriate city official assesses the situation by reviewing the request and determining if the area qualifies for treatment. Typical steps taken to evaluate include: 1. Determine if road way is eligible for traffic calming treatment. 2. Research city records on the history of the location and collect any accident, speed or volume data available. 3. Check roadway type and conditions. The primary purpose of a preliminary evaluation is to determine first, if the roadway area qualifies for any kind of treatment and then whether the speeding or traffic volume problem is significant enough to warrant further study. The preliminary evaluation is based on information already held by the jurisdiction, such as type of street; know traffic volumes, and accident histories. However, in cases where there are no known traffic volume available, a traffic count should be conducted. No Action Table 1 Street Classification Criteria Jurisdictions 1 Street Classification Local Street et I Residential Collector Alexandria, VA Asheville, NC 1 Bellevue, WA' 1 Bloomington, IL 1 o Bothell, WA 1 Canada Chattanooga, TN o Overland Park, KC Portland, OR Roswell, GA 2 Sandy, OR Sandusky, OH 3 Seattle, WA Sebastopol, CA Snohomish County, WA Note: o Streets not considered for traffic calming If the request for a roadway area is judged to be not significant, it is handled differently by the various jurisdictions in the study. For instance, cities of Asheville, Sandy and Sandusky, inform the applicant by letter or community meeting that their request does not meet city criteria for funding. Some jurisdictions, when a request is deemed not warranted at the current time, place the request on hold for reevaluation at a later date. The City of Alexandria has a two -year waiting period, and City of Sandy has a one -year waiting period before a re- evaluation of the situation takes place, unless there is a significant change in the transportation network in the affected area. 1 Residential Collectors the traffic volume has to be less than 6500 per day. 2 Streets are classified with each device used. 3 Residential Collector has to be 750ft or more in uninterrupted length 4 Any arterial road as long the posted speed limit is less than 35 mph Level I If the requested roadway is eligible and determination is made to address the problem, then the first line of action is usually some type of passive traffic control, which is Level I. Level I treatment as it is explained in the previous page is a less restrictive measure and usually does not require any further evaluation beyond the preliminary evaluation. In some jurisdictions, such as the cities of Chattanooga, Portland, and Sebastopol, Level I- type solutions are considered in cases where the street does not meet the criteria to warrant traffic calming improvements. Level II If Level I improvement strategies are ineffective, Level II solutions may be considered. Level II actions require a more detailed evaluation. Qualification criteria for Level II action varies by jurisdiction. If further study is warranted, the appropriate city official makes a more detailed field review and study of the situation. A detailed evaluation typically includes as follows: The speed and volume data collected during preliminary evaluation. Additional speed and volume data, which may be collected. (Data collection should be done on weekdays, September through May, when public school is in session.) Accident history, usually from three consecutive years. Other factors such as proximity to schools, parks and other pedestrian destinations lack of sidewalks, accessibility and special needs issues, bicycle accessibility, roadway characteristics. Table2 below illustrates the Average Daily Traffic criteria for Local Street and Residential Collector of the different jurisdictions. The three major criteria of traffic calming of a Level II solution include minimum speeding, minimum or maximum traffic volume and history of accidents correctable by traffic calming measures. Detailed list of the criteria are as follows: Traffic Speed: When considering traffic speed on residential streets, the majority of the jurisdictions use the eighty -fifth percentile speed. (The eighty fifth percentile is the speed which no more than fifteen percent of the drivers are exceeding.) The speeding criterion is met if 15% of the motorists on any street travel at 5 -1 Omph or more above the posted limit. Not all the cities follow this measurement. The City of Sandusky, for example, requires 55% average daily traffic exceeding the posted speed limit. Traffic volumes: In order to warrant traffic calming devices, most jurisdictions require volume on local streets and residential collectors to range between 300 and 3000 vehicles per day. If the traffic volume on any street proposed for traffic calming exceeds 3000 vehicles per day, traffic calming devices are not considered. (One exception to this rule is the City of Alexandria, which requires 3000 or more vehicles per day for local street usage, and 7000 or more vehicles per day for residential collector.) Accident History: When evaluating accident history, most jurisdictions use data from three consecutive years. In order to be included in the count, the accidents must be correctible through implementation of traffic calming devices. Table 2. Traffic Volume Criteria Jurisdiction Local Street Alexandria, VA Asheville, NC Bellevue, WA Bloomington, IL Bothell, WA Canada' Chattanooga, TN Overland Park, KC Portland, OR Roswell, GA Sandy, OR Sandusky, OH Seattle, WA Sebastopol, CA Snohomish County, WA <3000 >1000 300 3000 900 -3000 500 -2900 3000 >1000 >750 >1000 500 >500 >600 Traffic Volume (ADT) 1 Canadian guideline: the criteria are defined with each device. Residential Collector >7000 6500 >2500 2700 >1000 The evaluation process generally scores each request against the criteria to prioritize the request. Examples of rating charts used by other jurisdictions are included in Appendix A. After scoring requests staff creates a priority list of the requests based on the scores. The primary purpose of the prioritization is to assist staff objectively in determining where the limited funds for the traffic calming program would best be allocated. In general, based on the available resources, a jurisdiction undertakes a limited number of traffic calming projects each year. Those that are not addressed in the given fiscal year usually are placed on a waiting list. These requests are dealt differently by the different jurisdictions. For example, in Alexandria, the program specifies that if an eligible street segment remains on the list without receiving assistance for one year, two points are added to its worksheet score to compensate for a likely increase in traffic volume. In Portland, if after three years a project has not been prioritized high enough to proceed, the request drops from the program. However, the project may be reentered in the program ranking at the request of a neighborhood and/or neighborhood association. In Snohomish County, a project deferred for more than five years must be re- evaluated. Plan Develonment Generally, once an area has been selected for a traffic calming project, traffic engineering staff holds a public meeting to inform residents of the pending project. All property owners within the affected area should be invited. In Alexandria and Roswell, before a neighborhood meeting is called the staff first meets with the Fire Department to determine any specific emergency requirements of the street. The initial meeting typically includes: A discussion of the steps to develop a traffic- calming plan A definition of the neighborhood The formation of citizen traffic committee. The committee usually consists of about 4 -10 residents who work with the city staff during this stage. The neighborhood committee should be representative of the entire impacted area rather than concentrated on one or two streets. Once the committee is formed, it functions as a liaison between the city and the neighborhood. The city staff work closely with the neighborhood committee to identify the petition area and to find traffic calming measures that most realistically addresses the traffic concerns of both the residents and the city. The committee informs the residents of the traffic calming process and assists in obtaining the required number of signatures needed. Also, the committee is involved in developing preliminary design options and in estimating costs for review by the neighborhood at public meetings. Following the initial meeting, some jurisdictions require an approval threshold in order to proceed. For example, the cities of Ashville, Overland Park, Sebastopol, Sandusky, and Bloomington, require signatures be gathered from 40 to 60% of the households in the impacted area in order to proceed with the next phase of project development. Final Ballot The next step in the implementation process is to find out if the project has sufficient support of the neighborhood to warrant funding. A ballot is sent to each property owner in the impacted area. The property owners are asked to vote on the issue. Usually between 60 -70% approval of all residents in the impacted area is required in order to proceed. In addition to community support the, approval of the following public officials is required: The City Police/Fire Department The Transportation committee The Mayor and City Council Once the necessary level of support is determined, projects are funded according to their prioritization. However, when a plan does not receive sufficient support, the project is dropped from the list and the next highest ranked project is selected. Residents in an area where a project has been dropped may resubmit their request for the next program year. Final Design Once traffic calming treatments have been agreed upon and approved, the city's staff develop detailed plans, based on the study and the resident's input. In some jurisdictions, neighborhoods need to sign of on these plans before they can be implemented. For instance, in the cities of Overland Park, Roswell, and Asheville, the landscaping installation, maintenance and necessary easement dedication is the responsibility of the residents or the homeowners associations. Before the project is constructed, an agreement must be signed between the city and residents. In the City of Roswell, the neighborhood must also agree to share the cost as explained in the funding section. Proiect Funding The number of traffic calming projects initiated and the number of projects undertaken each year depends on a city's budget and the neighborhood's willingness to participate in sharing the cost. More than 2/3 of the jurisdictions' traffic- calming projects are city funded. However, some jurisdictions require neighborhood participation. Table 3 below shows different funding structures. Table 3 Funding Solutions Jurisdictions Fully Funded by Shared Jurisdiction Funding Alexandria, VA Asheville, NC Bellevue, WA Bloomington, IL Bothell, WA Canada Chattanooga, TN Overland Park, KC Portland, OR Roswell, GA Sandy, OR Sandusky, OH Seattle, WA I Sebastopol, CA 1 Snohomish County, WA 1 Some specific examples of funding strategies are as follows: In Roswell, citizens are responsible for 25% of the total cost of the traffic calming device(s); but, if the neighborhood is unable to share the cost with the city, then they can submit a letter of exemption. The mayor and council vote on whether to grant a neighborhood an exemption. In Asheville and Snohomish County, homeowners or civic associations may elect to pay 100% of the construction cost to expedite a low priority project while the other high priority projects remain on schedule. In Sebastopol, the neighborhood is asked to pay for engineering analysis work; funding for improvement projects may also depend on the financial participation of residents in order to move forward to construction. In Sandy, 50% of the cost is funded by the neighborhood. Construction For the majority of the programs studied for this report, once project design is approved and funded, construction starts within one to three months of approval (or as soon as possible). About 2/3 of the jurisdictions studied use test installations to assure that the traffic measure device are both effective and truly desired by the community. Test installations are usually done once the fmal proposal is agreed on by the area residents and jurisdiction staff. Within three to twelve months after installation, the staff evaluates how well the test installation performed in terms of the defined problems. Some jurisdictions require additional approval from the impacted residents following the test implementation before installing a permanent device. In this case the majority of the neighborhood must respond favorably. In cases where cities do not practice test installation, the project is constructed and inspected following standard city's procedures. Evaluation Between six months to one year after construction of calming devices an evaluation should be conducted. Speed, volume and collision data are compared with the data collected before the device was installed. The data should be collected in the same month as pre calmed data was collected. In addition, city staff should conduct neighborhood surveys, to evaluate the perceived effectiveness of the project as well as project acceptance. Removal and /or Modification of Treatments After the installation of the device, the neighborhoods may request the removal or modification of the devices if residents of the impacted area feel the strategy has not achieved the goals defined in the public process. This request is accompanied by signatures of over 50% of the households within the defined impact area. If the task force agrees that the implemented device is defective, then staff comes up with a plan, which then goes to a neighborhood vote. The number of owners voting in favor of the modification or removal of the device must be over 60 -90% of the total ballots issued. However, if a public safety issue is identified after the installation of any traffic calming measure, the city traffic engineer may direct modifications to be made without the required property owners' approval. The removal process of the traffic calming improvement device may not be started until the measures have been in place for at least one year. Removal of traffic calming treatments seems to be rare in all of traffic calming programs studied. In the majority of the jurisdictions, residents of the affected neighborhood would pay for the removal of the traffic claming device, unless it is a safety issue. City of Alexandria allows no removal of a device unless it is compromising the safety of the neighborhood residents and/or the drivers. Level III Two jurisdictions, City of Bothell and Snohomish County, have a specification of Level III improvements. In both cases, the solution is applied on larger -scale neighborhood projects or when the neighborhood problem is determined to be caused by a lack of adequate arterial facilities and sidewalks in the problem area. Information on Sample Data Set The data used in this report was gathered from a group of jurisdictions representing a wide range of characteristics. Effort was made to include jurisdictions of varying sizes, as well as geographic location. Table 4 below illustrates the variation in population, annual budget, annual average number of traffic calming requests received, number of employees dedicated to traffic calming projects, and the number of traffic calming projects each jurisdiction takes up per year. Table 4 Jurisdiction Profile Jurisdictions Alexandria, VA Asheville, NC Bellevue, WA Bloomington, IL Bothell, WA Canada' Chattanooga, TN Overland Park, KC Portland, OR Population of Jurisdictions 125,000 1 112,000 30,900 150,000 163,000 530,000 85,000 62,000 27,000 1,000,000 7,500 600,000 Traffic Calming Budget Per Year $400,000 $375,000 $15,000 $25,000 $50,000 $100,000 Roswell, GA Sandy, OR Sandusky, OH Seattle, WA Sebastopol, CA Snohomish County, WA Note: Cities of Overland Park, Sandusky, and Sebastopol, do not have calming. $80,000 $10,000 $200,000 $70,000 Average Number of Request Received Per Year 27 40 -60 12 26 50 50 100+ 12 10 2 -3 300 -400 6 -8 40 -50 Number of Number of Employees Projects Working Undertaken On Traffic (Per Year) Calming 1 1 6 3 1 1 -2 2 4 1.25 plus administrative 5 -10 support 3 t 1 -3 1 1 -2 1 2 -7 1 1 exclusive budget for traffic- 8 -10 1 -3 2 -3 15 -20 2 20 -25 1 6 -8 'Canada, unlike the United States, has a multi jurisdiction neighborhood traffic calming program which is used throughout the nation; therefore, the budget varies with each jurisdiction. 2 The $50,000 budget per year budget does not include labor. 3 City of Roswell has no specific budget solely for traffic- calming; the city's program is fairly new but has already installed two temporary traffic calming programs this year. 4 10,000 budget per year is only for the traffic- calming device; it does not include other traffic- calming treatment. Additional Information The City of Bellevue has a budget of $375,000 per year for neighborhood traffic calming. The city has no prioritization system. It has sufficient resource to do 3 -4 projects of Level II every year. In Bellevue, educating the neighborhoods and involving citizens early on in the implementation process is considered a very important part of the traffic calming program. Much of the programs success can be contributed to adequate funding and a dedicated staff of three personnel. The City of Seattle's program is more spot oriented and not area oriented. The City's annual budget has been reduced from about Imillion in 2003 to $200,000 for the year 2004 (an 80% drop). The city allows for neighborhoods to share the cost. If residents are willing to pay 50 percent of the cost for pre construction data collection and engineering and the installation of the traffic- calming device, the neighborhood may install traffic calming device. The city's program mostly concentrates on traffic circles and speed humps. However, currently the city has not done any traffic- calming projects in 2004 due to the large budget cut. The City of Alexandria has an annual budget of $400,000 to $500,000 for neighborhood traffic calming. Unlike cities such as Roswell, Sandy, and Seattle, the City of Alexandra doesn't allow neighborhood participation on cost sharing. Allowing the neighborhood to share the cost would favor the streets with neighborhood of higher income. And, the streets where neighborhoods with low income, which really need traffic- calming, might not get the attention needed. The city's traffic-calming is done according to a prioritization list. The City of Bothell does not have priority ranking. They use a "technical committee" which includes representatives from the police department, traffic engineers and maintenance department that make decisions about which local street qualifies for the traffic- calming budget. Summary The major cause for traffic calming request stem from speeding. Since speeding has the largest impact on livability and safety, in all evaluation procedures it is given the most weight. It is also the condition that can be most easily improved using traffic calming measures. However, correctable accidents do not appear to be the major cause of traffic- calming request for the jurisdictions considered in this report. The conclusion one might make from this fact is that community members are very concerned about safety in their community, and often want to take measures before an accident occurs. In implementing traffic calming programs, a recurring theme through all the jurisdictions programs was the need for set criteria, and involvement of the community. All the jurisdictions have set procedures, which include similar levels of public involvement. All jurisdictions voiced concern about budget. Some felt they did not have adequate budget, while others were concerned about maintaining their current budget. One distinction is the issue of whether or not to allow private participation in financing for traffic- calming improvements; and if so, to what extent. One concern about allowing private participation is that it might lead to traffic- calming efforts only being implemented in the more affluent neighborhoods. An interesting point for further study would be the reception which implemented traffic- calming efforts have met in the neighborhoods. Append A Priority Ranking Criteria Sample The following Tables are different choices of priority ranking used by different jurisdictions: City of Overland Park Rating Chart: 1 Criteria 1 Basis for Point Assignment Speed 5 points assigned for every mph greater than 5 mph above the posted speed [(85th percentile speed limit 5 mph posted speed limit) x 5 points] Volume Average daily traffic volumes (weekday) (Residential) 1 point for every 100 vehicles Volume Average daily traffic volumes (weekday) (Collector) 1 point for every 300 vehicles Schools 5 points assigned for every school within the impact area and 2 points for school property within 500 ft of the impact area Sidewalks 5 points assigned if there is not a continuous sidewalk on one side of residential streets or both sides of collectors Sidewalks 5 points subtracted if the street is a primary emergency vehicle response Response route Accidents 5 points assigned for each recorded accident (15 points if it is a disabling injury accident) per mile of roadway (past three year's total) 1 City of Asheville Rating Chart: 1 Criteria 1 Points 1 Basis for point assignment Speed 0 to 40 4 points assigned for every mph greater than 5 mph above the posted speed limit (using the full day 85th percentile speed)* 1 Volume 1 0 to 20 1 1 point for every 200 vehicles per day.* Crash history 0 to 10 1 point assigned for each 0.3 recorded crashes per year per mile of roadway (based on the past three years) 0 to 10 4 points for each elementary or middle school within 500 feet of the project area. 2 points for each other school, bus route, park, or community center within 500 feet of the project area. 2 points should be given if any (not for each) retail, commercial, or other institutional (including churches) uses exist within 500 feet of the project area. 0 to 8 Each street segment will be rated on a scale of 0 to 8 for potentially hazardous roadway geometry and other factors. Factors to be considered include horizontal and vertical curvature, street width, proximity of homes to the street, stopping sight distance, intersection sight distance, and driveway sight distance and geometry. 0 to 7 1 point assigned for every 25 dwelling units per mile. Pedestrian Generators Roadway Geometry Residential Density Sidewalks Total Points 100 Possible 0 or 5 5 points assigned if there is no continuous sidewalk on at least one side of the street. *For streets that exhibit cut through traffic characteristics during specific hours, the following alternative method may be used if it results in a higher score. For speed: 3 points for every mph greater than 5 mph over the posted speed (using the 85th percentile speed calculated during heavy cut through traffic periods). For traffic volume: 1 point for every 20 vehicles per hour during the peak hour recorded on the street. City of Seattle Criteria Speed (85 Percentile Speed) Volume ADT (Weekday Traffic) Accident History (Over 3yrs) Rating Chart: (Point Criteria) Points Traffic Speeds (mph) 0.5 26 -29 1.0 29.1 -32 1.5 32.1 -35 2.0 35.1 -38 2.5 38.1 -41 3.0 41.1 -44 Points Traffic Volumes 0.5 500 -1100 1.0 1101 -1700 1.5 1701 -2300 2.0 2301 -2700 Points Annual Accident Rate (acc /yr) at intersection .5 If accidents on a midblock section exceeds 2 /yr over the last 3yr 1 .5 -0.875 2 0.586 -1.250 3 1.251 -1.625 4 1.626 -2000 5 2.001 -2.375 6 2.376 -2.750 ethod Potential Degree of Effectiven Advantage Disadvantages n Reduction Depe nden Police Enforceme Construe i NIA NIA Spee Watch Program Radar Spee Trailer Target E Striping Mid i Mdd Ve getation Trim Impro S ignag e Tr fficSafety Campaig Multi -way Stop �li1d Educates residents on what the legal speed linitlee nt Educates like tom' •edestrian stand motorists of their current, actual speed 1 ti ed of travel the Makes motorists aware of the activeness of community h are drivin Reduces speeds and rases awareness of drivers. Mild of road Can srg •d visual du h bltual Corre Probably not e ing points for Creates more stopp M to Moderate 1 Vehicles ins allocations Addressescoo eat with confectp Iraq dUC0 Does not reduce speeds or Volumes. Only changes in motorists while in place. Some motorists use the reader board teclock' how fast they can g ram is ongoing Very Slght Staffing needs vary E{{eceve only when ba ed o n area s� -c+fic need i used method of speed Notcomino Y control Degree of effectiveness may vary substanti Unlikely Must be No stant! mainta --1 nik IY Must be constantly ma onitored d planning to Requires monit� g NIA Only when possible NIA Possibly Improve Sign If ciensres avo► yr eC ti v e to a possible d yes awareness viorato� have a program i N regulations City does not currently c ooperatio n, o f pr and Rn S d appreciaf awareness, of g estabeshe coop general Requires develop meat and progr motoftrtg public. an Continuation of staffing I when actmay be reduced newness' of To ram is lost Stop signs that are installed that tdon't e often meet engineering warrants sear ten not obeyed by motorists lam with pedestrian safety if not 1 e intersection Can rd correctly installed top signs as speed Should not use ouldbe used to control. stop signs should intersections owl define ri hw N o NIA Unllkely Increased Possibly Improved visual pollution Slight Sight N I A posSSbly i Improv Improv Ii Increased \I\ Nixed N NIA IA Low o Moderate Low None t Hig Can be used i conjunction with target enfo� rese NIA NIP High N Problem NIA None 1 NIA N(A I NA NIA I m g provement None NIA Low to Moderate \Low Moderate 1 Low Moderate to H No p oblem NIP Low to Moderate Moderate Low L Low Method Potential Degree of Effectiveness Advantages Disadvantages Volume Reduction Speed Reduction Noise Pollution Safety Access Restrictions Emergency Vehicle Access Dependence on Police Enforcement Operation and /or Construction Cost Maintenance Cost/ Problems Pedestrian Safety Measures Gateway/ Entrance Treatment Traffic Circle Creates clearly defined areas for pedestrians Provides safer areas for pedestrians Moderate Provides visual transition between arterials and residential areas Can improve pedestrian crossing safety on wider streets Moderate Moderate Requires reduction in vehicle speed without use of stop signs Removes conflict potential for many types of accidents Turn Prohibitor: Moderate Can reduces through traffic. Signing restrictions Chicane Moderate Effectively slows motorists traveling through and approaching the treated section Can be designed to improve pedestrian safety. P: \Cyndy \Traffic Calming \MATRIX2 General Comparision.doc Traffic Calming Methods GENERAL OVERVIEW Painted crosswalks could create a false sense of security for pedestrians Pavement markings require additional maintenance. Speed change could result in rear -end accidents May move traffic /problem to other roads Neglect of landscaping can become a sight distance problems Neglect of landscaping can become neighborhood "eyesores" Ongoing maintenance costs Definition of who is responsible for maintenance possible landscape maintenance agreements with residents May be restrictive for larger vehicles or Possible vehicles with trailers May move traffic /problem to other roads May require additional lighting May be confusing for left turns May require additional Right -of -way Requires consideration for aesthetics Requires consideration for maintenance of landscaping, if used Moves traffic /problem to other roads Yes Inconveniences local residents in gaining access to their property Becomes an enforcement problem Moves traffic /problem to other roads Yes May be restrictive for larger vehicles or vehicles with trailers May require additional lighting Can create confrontations between opposing motorists Fire codes requirement must be maintained Requires consideration for aesthetics Requires consideration for No No N/A Possible Slight No Mixed None Possibly None Improved Likely No Change Improved None Possible Decrease Mixed Somewhat Restricted Yes Decrease Mixed None No Problem N/A No Problem N/A Some Constraint Minor Constraint Minor Constraint Low Moderate to High Low N/A Moderate Low to Moderate Low to Moderate/ Possible Vandalism Moderate Moderate Moderate/ Possible Vandalism Moderate/ Possible Vandalism Moderate to High Moderate to High /Possible Vandalism Method Potential Degree Advantages of Effectiveness Disadvantages Volume Reduction Speed Noise Reduction Pollution Emergency Vehicle Access Dependence on Operation and/or Maintenance Cost/ Police Construction Cost Problems Enforcement Speed Hump Turn Prohibitor: Physical deterrent Diagonal Road Closure Street Closure Extreme Reduces speeds of vehicles at and in the vicinity of the bump Can be designed for any speed Better if used in a series of 300 to 500 foot spacing. Moves traffic/problem to other roads Y es Inconveniences local residents in gaining access to their property Can affect emergency vehicle response time Becomes an enforcement problem Not viable in most locations Moves traffic /problem to other roads Inconveniences local residents in gaining access to their property Not generally supported by Fire Department Affects emergency vehicle response time Eliminates through traffic Reduces accessibility of emergency Can reduce speed of remaining vehicles traffic Forces the problems onto another Improves safety on the street street closed Reduces access to properties by residents Extreme Reduces through traffic. Extreme Eliminates through traffic Provides for landscaping Reduces conflicts Increases pedestrian safety. Extreme P: \Cyndy \Traffic Calming \MATRIX2 General Comparision.doc Traffic Calming Methods GENERAL OVERVIEW Safety Access Restrictions maintenance of landscaping, if used Causes increased noise from braking Possible Yes and accelerating vehicles, particularly if there are loose items in the vehicle May move traffic /problem to other roads Causes delays in emergency vehicle response time Not supported by Fire Department Can cause damage to fire trucks during emergency responses Yes Yes Increase at Improved None humps Likely Decrease Improved Restricted Likely Decrease Improved Left or Right turn Some Constraint Yes Decrease Improved Yes Minor Self Enforcing Moderate constraint Some Constraint Some Low Constraint Moderate to High Moderate to High Moderate/ Possible Vandalism Low to High, High dependent on features Moderate/ impacts street sweeping, snow removal Moderate/ Possible Vandalism Moderate to High Moderate to High /Possible Vandalism Method Description Picture Descri tions of Traffic Calmin Methods Speed Watch Residents check out radar gun and gather Program speed data in spot Locations Data gathered is used to validate other speed data Residents learn what certain speeds 'feel like' when standing on or near the roadway Radar Speed Offered through the Police Department, the Trailer speed reader trailer is placed in neighborhood locations on a rotating basis Can be used in conjunction with a target enforcement emphasis traffic officers can be found further down the road to provide police back up of the legal speed limit Target A progressively_ stricter enforcement schedule Enforcement with low thresholds for citations Traffic officers work a select location over a period of time, graduating from marked police cars to ultimately unmarked cars The Radar Speed Trailer shown above is generally part of the process Striping Installing center, walkway, and edge line markings to narrow or modify the travel lanes Unique striping in individual cases can be used successfully Striping can include: yellow center skip strip white edge lines wording on pavement bike lanes Applications are determined in each instance and can be modified to fit individual needs Paint cannot be applied year round weather dependent installation Striping an unstriped roadway gives the appearance of a narrowed road and assigns where vehicle and pedestrian areas are located None available None Available Vegetation Trimming Descri tions of Traffic Calmin Methods Method Description Picture City crews will trim vegetation in public right -of- way to improve sight distance at intersections, sign visibility, or general safety Vegetation that is in private property can only be trimmed by city crews if impeding sight distance or creating a safety hazard Property owners are always first encouraged to trim their private plantings Improved Signage Signs already in place may be improved by installing larger signs, or signs made of high intensity background material New signs may be installed as warranted Existing signs may be relocated to provide maximum impact Traffic Safety This program is currently not defined by the City Campaign of Bothell Could include development of traffic safety brochures or flyers Could be developed to incorporate local high school education Multi-way Stop All -way, or multi-way stops are installed at intersections where traffic flows are generally fairly equal on all legs Engineering warrants must be met before installation can occur New standards are being studied at the federal level for new installation criteria of all -way stops within residential areas Pedestrian Safety Not currently fully defined by the City of Bothell Measures Improvements can include: Sidewalk or walkway installation Crosswalk installation paint textured pavement treatment Pedestrian signals (many variants) Pedestrian scale lighting improvements Pathways None Available None Available None Available 7 Sample of textured pavement crosswalk Method Description Picture Gateway! Entrance Treatment Descri tions of Traffic Cafmin Methods Sometimes called planter islands, these are typically long and narrow islands placed in the middle of roads at intersections On wide streets, curb extensions may be used on both sides of the roadway while still maintaining 2 lanes of roadway width In some cases, pedestrian amenities such as raised crosswalks, decorative pavement, or simple painted crosswalks are also included as part of the treatment May also include additional street lighting for the intersection and decorative entrance signs Traffic Circle Round islands installed at intersections to force traffic to circle around the island, thus disrupting the flow of traffic Less expensive traffic circles can be painted on the asphalt, marked with raised pavement markers More costly traffic circles are made with curbing and back filled with asphalt The most expensive traffic circle to construct include curbing and removal of existing asphalt from the center. Soil and approved landscaping are brought in and ultimately maintained by the surrounding residents 2 j Island i .o Traffic Flow Method Description Picture Chicane Speed Hump Turn Prohibitor: Signing restrictions Descri tions of Traffic Calmin Methods A series of tight turns in a straight section of road that restricts traffic speeds Bothell Fire Code prohibits chicanes or any other treatment from narrowing the road to less than 20 feet Chicanes can be made of wooden traffic barricades, curbing with fencing, curbing with asphalt back fill, or curbing with landscaping In some instances, chicanes can be combined with on -street parking A raised mound of asphalt across the roadway that reduces speeds as vehicles travel over them Speed humps can be designed for many different speeds To be effective, speed humps need to be placed 300 -500 feet apart and installed in a series of typically at least 3 humps Not approved on primary emergency response routes or on major transit routes Signs are placed at intersection to restrict certain turning movements or to only allow a certain movement Restrictions can be all the time or can be during certain times of day only NO LEFT TURN /AsphdtBurrp' 3.5" max. r ONLY either can be implemented for specific times of day Descri tions of Traffic Calmin Methods Method Description Picture Turn Prohibitor: Physical deterrent Also known as half or partial closures or diverters Physically directs traffic flow at intersections, prohibiting specific movements Many variations can be implemented, depending on the need of the particular street Can be combined with pedestrian amenities such as textured pavement or raised crosswalks Method Picture Diagonal Road Closure Descri tions of Traffic Calmin Methods Description Diagonal road closure completely close a road to through traffic without completely closing a road Diagonal diverters can be used to fully or partially divert traffic Implementation can be done by using wooden barricades, concrete barricades, curbing, and landscaping Diagonal diverters are not applicable in most places as minimum travel lane widths of 20 feet must still be maintained Street Closure Streets are closed to through traffic by forming a cul -de -sac or hammerhead Additional right -of -way may be necessary to construct the cul -de -sac or hammerhead Street closures are not applicable in most locations Traffic Flow