Neighborhood Traffic Management Program (NTMP)

What the program is

The Neighborhood Traffic Management Program (NTMP) represents the City's commitment to the safety and livability of residential neighborhoods. It is a joint effort between residents, the Public Works Department, and Sammamish City Police. The program aims reduce the impact of traffic on neighborhoods. The NTMP provides a process for identifying and addressing traffic concerns.

Under the program, Public Works (PW) staff and City Police work with residents to evaluate traffic issues. Through active participation by community members, we can identify the type and severity of problems. Then we plan an approach to address the problems. After implementing solutions, we evaluate their effectiveness.

The City of Sammamish places a high value on neighborhood livability. Although livability has no precise definition, it can be thought of as encompassing the following characteristics:

• The ability of residents to feel safe and secure in their neighborhoods.
• The opportunity to interact socially with neighbors without distractions or threats.
• The ability to experience a sense of home and privacy.
• A sense of community and neighborhood identity.
• A balanced relationship between multiple uses and needs of a neighborhood.

Traffic management plays a vital role in promoting these characteristics.

Program goals

The overall goals of the NTMP are derived from existing city policy. They are:

• Encourage and promote citizen involvement in all phases of neighborhood traffic management activities.
• Improve neighborhood livability by reducing the speed and impact of vehicular traffic.
• Promote safe and pleasant conditions for residents, pedestrians, bicyclists, and motorists.
• Utilize city resources efficiently by prioritizing traffic management requests.
• Support the policies contained in the Transportation Element of the Comprehensive Plan.

Process

The program is a two-phase, two-year process:

• Phase I focuses on passive, less-restrictive measures. This includes educational programs, enforcement, pavement markings, and signing.
• Should “Phase I” actions prove ineffective, more restrictive “Phase II” methods and physical devices may be considered. These are based on certain threshold criteria.

Neighborhood Traffic Management Program: Phase I

Education, Public Awareness, Enforcement, and Passive Measures

The first step is to identify the traffic concerns in your neighborhood and inform the city’s Public Works Department. You can do this by using the online My Sammamish Fix It portal.

Following to this step, you may submit a formal letter addressed to:

Sammamish Public Works Department
801 228th Ave SE
Sammamish, WA 98075

The City must receive your formal request in writing to place your neighborhood on the list. Your neighborhood must submit a formal letter to be scheduled for evaluation.

Once we receive your request, a site visit will be conducted to review current traffic control measures. These include pavement markings, signs, sight distance, and road conditions. Next, we will collect pertinent data (historical traffic data, volume and speed counts, etc.).

From this information, Public Works staff and City Police will compose a Neighborhood Traffic Plan for the location. Staff will inform you of our findings and recommendations for Phase I solutions. This review takes approximately 6 to 8 weeks from the day we receive your request.

Possible Phase I solutions may include one or more of the following:

Neighborhood Speed Watch: 

This program is a public awareness program addressing and impacting the problem of numerous vehicles exceeding legal speed limits. The program solicits concerned residents as volunteers to actively participate in reducing speeding in their neighborhoods.

The City Police Department furnishes training and equipment for program volunteers. Volunteers will record speeds and vehicle license numbers of cars traveling in excess of the legal speed limit. Two volunteers are usually needed. While one volunteer clocks speeds and states information, the other records it. (Additional details are available from the Police Department).

Upon receipt of the data, the City obtains the names and addresses of the registered owner of the recorded vehicles. The City sends notices encouraging the owners or drivers of the vehicle to observe the speed limit.

Traffic Trailer:

A portable trailer equipped with a radar unit detects and records the speed of passing vehicles. It displays their speed on a digital reader board. The trailer displays actual speed compared to the posted speed limit and encourages compliance.

Neighborhood Traffic Safety Campaign:

This program involves a personalized newsletter mailed or distributed to your neighborhood. The newsletter explains:

• traffic volumes and speeds in your area,
• recommended traffic calming measures,
• traffic laws,
• pedestrian safety, and
• other relevant information.

Brush Trimming:

The trimming and removal of brush by homeowners or City staff to facilitate better sight distance.

Pavement Markings:

The painting of legends and markings on the pavement. These may include centerlines, fog lines, crossings, and speed limits.

Signing:

The posting of appropriate traffic control signs. These may include speed limit, parking, dead-end, no outlet, school signs, etc.

Target Enforcement:

Increased enforcement by Sammamish Police Department.

Once the Proposed Improvement Plan is complete, Staff will work with citizens to initiate recommended solutions. Approximate timeline: 12 to 16 weeks.

Neighborhood Traffic Management Program: Phase II

Traffic Calming Projects

About 32 weeks after implementing Phase I of the program, Phase II begins. The City again collects data and compares it to Phase I data. If the data demonstrate that traffic concerns still exist, the location will be considered for physical traffic calming devices.

Possible Phase II solutions may include, but are not limited to, the following physical devices:

• Choker and Curb extensions
• Traffic circles
• Partial closures
• Chicanes
• Entry treatments
• Raised intersections
• Medians

Step 1: Project Consideration and Preliminary Review

PW staff reviews and gathers additional data if necessary. The potential project is rated using “Point Assignment for NTMP Projects” (Attachment A). The numerical score helps determine placement on a priority list. Approximate time line is 4 to 8 weeks.

Step 2: Plan Development

A public meeting is held to inform residents of pending project and to gather further information. PW staff is responsible for public notification. Approximate time line is 4 to 6 weeks.

Step 3: Ballot for Design and Construction

The project plan is modified if necessary and placed on a funding priority list. The requestor is then responsible for circulating a ballot in support of permanent device construction. A 60% signature rate is needed to proceed.

Final design and construction are contingent on funding. Approximate timeline is 16 to 26 weeks (Target for construction is 100 weeks from original Phase I request date).

Step 4: Reporting of Design and Construction

PW staff generates a report of the final design and construction schedule. They distribute it to the study area, preferably through an active HOA or neighborhood point of contact. Approximate timeline is 4 to 8 weeks.

Step 5: Landscaping

Initial installation costs associated with landscaping will be covered by the City. Landscaping of NTMP devices may be feasible. If feasible and desired by the neighborhood, maintenance will be negotiated with the neighborhood and/or adjacent property owners. The neighborhood will be responsible for ensuring the landscaping does not obstruct the view of traffic or become unsightly. If the neighborhood fails to fulfill their assigned maintenance responsibility, the City reserves the authority to remove the landscaping.

Step 6: Follow Up Evaluation

Within three to five years after construction of an NTMP project, the Public Works Department will conduct a follow-up evaluation. They will assess whether the project’s goals and objectives continue to be met.

Attachment A

Point Assignment for NTMP Projects

The following information is used to develop a numerical score for each NTMP project request. Scores are used to rank requests on a citywide basis. A high-ranking, available budget, and other factors are used to determine which projects will precede to the petition-to-study stage.

1. Traffic Volume: Average daily volume (on the segment of the project street having the highest volume) divided by 100. Thirty points maximum score.
2. Speed: Percent of vehicles over the speed limit divided by three. The percent is drawn from the segment of the project street having the highest percentage over the limit. Thirty points maximum score.
3. Accidents: Ten (10) points per correctable accident in the most recent three-year period. Thirty points maximum score.
4. Schools: Five points for each private or public school in the affected neighborhood. Ten points maximum score.
5. Other Pedestrian Areas: Five points for each individual pedestrian-oriented facility. Examples include churches, daycare facilities, elderly housing, or a park in the affected neighborhood. Ten points maximum score.
6. Pathways: Five points for a subject street that is not bordered by a sidewalk or pathway. Five points maximum score.
7. Designated Bicycle Routes: Five points for a designated bicycle route. Points awarded when a subject street or cross street is designated as a bicycle route in the City’s arterial streets classifications and policies. Ten points maximum score.

Traffic Management Devices

This section provides a brief description of some commonly used traffic management devices.

Traffic circles are raised islands placed in an intersection. The primary purpose of a traffic circle is to slow high-speed traffic. Traffic circles are most effective when constructed in a series on a local service street.

Chokers or curb extensions narrow the street by widening the sidewalk or the landscaped parking strip. These devices are employed to make pedestrian crossings easier and to narrow the roadway.

Chicanes are similar to chokers or curb extensions by narrowing the existing street with an alternating pattern. These devices require the driver to shift his line of travel from one side of the street to the other. Installed correctly, chicanes may make the street appear to have a restricted or limited access.

Semi-diverters limit access to a street from one direction by blocking half the street to cars. Access is only available to bicyclists, pedestrians, and transit. They may also be constructed to limit certain movements (left or right turns and through movements) at an intersection.

Diagonal diverters place a barrier diagonally across an intersection, disconnecting the legs of the intersection.

Intersection channelizations are designed to limit certain movements, narrow the intersection, or otherwise direct traffic. They are unique to each intersection and can take a variety of forms. An example is a median island that restricts through movement.

Narrow Points reduce the roadway width to one 12-foot travel lane. The one lane requires drivers to take turns driving through the device. Narrow Points make the street more visually restrictive.

Traffic Control Devices

Stop Signs are used to assign right-of-way at an intersection. They are installed at intersections where an accident problem is identified or where clear right-of-way may be in doubt.

Stop signs are generally not installed to divert traffic or reduce speeding. Stop signs or multi-way stop intersections can be used in conjunction other traffic management devices.

Modern Roundabouts are traffic control devices approved by the city for controlling traffic and reducing accidents. They can be utilized in place of traffic signals or stop signs or in conjunction with same. Three principle design features distinguishing the Modern Roundabout from Traffic Circles are:

• Yield-at-entry
• Deflection
• Flare

Glossary

Street Classifications

All of Sammamish's streets are classified. The City's arterial streets classifications designate a hierarchy of streets. Classifications are based on the type of trips the street is intended to serve. They also identify the volume and speed of traffic. They are intended to guide future development of Sammamish's transportation system.

They do not mandate any specific projects or changes in traffic movement or transit service. The classifications and policies are not strict guidelines for current operation of Sammamish's street system. Some streets may not currently be operating in accordance with their classification.

Neighborhood Streets

Neighborhood streets make up the great majority of Sammamish's street neighborhood collector streets. These streets serve local circulation needs for autos, bicycles, and pedestrians. They provide access to land uses located on the street.

Local access or neighborhood streets should not carry significant volumes of through traffic. Most reported neighborhood traffic problems are concerned with the interactions of autos and residential livability on neighborhood streets.

Neighborhood collectors are intended to be the links between the local access or neighborhood streets, collectors, and arterial streets. Shorter trips and access to commercial uses should also be emphasized in the design of neighborhood collectors.

Major collector streets are similar to neighborhood collectors, except they serve larger geographical areas and/or more concentrated development.

Arterial streets are designed to serve trips between different sections of the city. They are also designed to allow access to abutting properties without disrupting traffic flow.

Speed

may be the most frequently discuss neighborhood traffic problem. Local access streets, except where otherwise posted, have speed limits of 25 miles per hour. As needed or requested, the Public Works Department will conduct a speed study. That determines the appropriate speed limit for a given street. The Public Works Department considers factors like land use, accident history, roadway type, and speeds currently driven by motorists.

Volume

is another of the most commonly reported local traffic problems. Volume refers to the number of vehicles that cross a given section of roadway during a specified time period. In Sammamish, volumes are normally measured on weekdays for at least 24 hours.

Accident history information

is used to determine safety problems at a given location. Accidents, particularly at low-volume residential intersections, are often random. An average of less than one reported accident per year usually does not indicate a safety hazard.

An average of one or more reported accidents per year can be significant. This is more likely if there is a pattern of several similar accidents having occurred. When a pattern is apparent, the problem can be identified and appropriate solutions developed.