PROGRAMS AND SERVICES
TRAFFIC CALMING PROGRAM
The program described herein applies only to local and minor collector residential roadways. This is because the sensitivity to maintain the character of these roadways, and because the primary function of these types of roadways is for property access rather than to accommodate larger volumes of through (bypass) traffic in a free-flowing manner.
The following objectives for residential roadways have been identified for the Alameda County Neighborhood Traffic Calming Program:
- Increase motorist awareness of the residential character of the neighborhood
- Reduce motorist speed
- Discourage bypass traffic on local and minor collector roadways
- Reduce traffic collisions
- Promote a pleasant environment for pedestrians, bicyclists, and non-motorized roadway users
- Improve community awareness in residential neighborhoods
- Maintain Emergency Service response time
In addition, the following are auxiliary objectives of the program:
- Involve local residents in developing the traffic calming program for their neighborhood
- Provide a step process, which is streamlined
and well-defined, to address residents' requests for traffic
calming measures
- Establish consistent screening criteria
for implementing traffic calming measures where applicable
- Establish design guidelines for installing
traffic calming measures
- Provide for prioritized, cost effective
implementation of traffic calming devices
Step Process
The process for developing and implementing
traffic calming measures in a neighborhood involves the participation
of the community and governmental entities including Public Works
Agency, Community Development Agency, CHP, and the Sheriffs and
Fire Departments. The following steps are included in the process
for implementing traffic calming measures (the responsible party
for each step is identified by italics):
- Define the neighborhood in terms of surrounding roadway network, circulation boundaries, and connections to arterial and collector roadways. (Public Works and the neighborhood)
- Determine the level of community support for the Neighborhood Traffic Calming Program (generally in the form of a petition letter from residents and property owners representing 2/3 of the neighborhood's properties). (Public Works and the neighborhood)
- Discuss the Neighborhood Traffic Calming Program with residents and/or property owners to identify traffic issues and determine objectives for the neighborhood. (Public Works and the neighborhood)
- Study traffic conditions (traffic volumes, motorist speed, on-street parking demands, typical travel routes, emergency service, etc.) and identify types of measures that may be applicable and effective in achieving neighborhood objectives. (Public Works)
- Develop a preliminary implementation plan
of traffic calming measures and alternatives and present the
plan to the neighborhood. (Public Works)
- Negotiate an implementation plan with neighborhood residents and specific affected property owners. (Public Works and the neighborhood)
- Revise implementation plan to assimilate comments from the neighborhood and commitments obtained from affected property owners and/or residents, if necessary. (Public Works)
- Negotiate appropriate financial participation from the neighborhood, if necessary. (Public Works and the neighborhood)
- Implement traffic calming measures including any necessary design and construction. (Public Works)
- Perform follow-up evaluation of whether neighborhood objectives were met. (Public Works)
- Repeat steps 5 through 10 if necessary.
When a physical traffic calming measure is approved, installation of the device will be installed after all appropriate steps are completed (environmental review, preparation of plans and specifications, construction, and inspection).
Guidelines for Construction
As part of the process in developing the design guidelines for the Neighborhood Traffic Calming Program, applicable roadway safety criteria from the following design manuals were considered:
- AASHTO (American Association of State Highway and Transportation Officials) - A Policy on Geometric Design of Highways and Streets
- Caltrans - Highway Design & Traffic Manuals
- FHWA (Federal Highways Administration - Manual on Uniform Traffic Control Devices
- ITE (Institute of Transportation Engineers) Design Criteria
- ACPWA (Alameda County Public Works Agency) Design Guidelines
The following are construction guidelines for the program:
- A step process will be used to apply traffic calming measures in communities.
- The device must be located on relatively straight, level roadway sections (i.e. tangents to horizontal and vertical curves)
- Proximity to intersections
- For speed humps, the roadway must have a gradient of less than five percent (5%) for a minimum of 230 m (750 feet) between intersections in the traffic calming area. Road humps may be used on roadways up to eight percent (8%). The minimum roadway section length may be increased for vehicle control considerations for steep grades adjacent to the roadway section under consideration. The roadway should have a minimum curb to curb or pavement width (unimproved shoulder) of 7.3 m (24 feet) or a maximum of 12.2 m (40 feet).
- Roadway illumination is required at the traffic calming device
- Devices, must be installed entirely within the County's right-of-way
- Devices must avoid conflicts with existing infrastructure: utilities, storm-drain facilities including gutter flow, landscaping and driveways
- Landscaping ownership and associated maintenance responsibilities must be agreed to by the adjacent property owners
- Community financial participation may be required for:
- right-of-way dedication (if necessary for the traffic calming device)
- sidewalk, curb, and gutter installation and replacement (if necessary)
- storm drain/utility relocation landscaping installation and maintenance
Prioritization (Screening) Criteria
The eligibility of residential roadways for the traffic calming pilot program will be determined by
the following criteria:
- Roadway should have a functional classification of a local or minor collector roadway. Classifications have been established with Caltrans and FHWA.
- ADT (Average Daily Traffic)
maximum volumes on local roadways: < 1,500 vehicles per day (vpd). maximum volumes on collector roadways: < 3,000 vpd.
- The posted speed limit must be not more than 30mph.
- The Critical (85' percentile) Speed must
be a minimum of 10 miles per hour mph above the posted speed
limit (typically 25 mph) for speed humps.
- Collision rates on the roadway should exceed Caltrans (District 4, Statewide, and countywide) figures.
- Lack of adequate vehicle gaps for pedestrian crossing.
- Roadways must have adequate width or shoulder area.
- An assessment of existing roadway facilities will be conducted, and additional consideration will be given to those roadways which have Portland Cement Concrete (PCC) curb, gutter and sidewalk. Existing roadway facilities that are on designated suggested routes to school, or are near parks, community centers, senior housing, retail establishments or other pedestrian generators will also be given special consideration even if PCC curb, gutter, and/or sidewalk improvements do not exist.
- Roadways should be of residential character.
Constraints, Guidelines, and Factors Affecting Design
- Enforcement efforts and traditional traffic engineering practices alone do not effectively modify motorist driving behavior
- Bypass traffic avoiding designated collector or arterial roadways by using local roadways
- Access for pedestrians, bicyclists, and other non-motorized users
- Preserving emergency vehicle access
- Access for buses (AC Transit, Paratransit), trash collection, moving vans, and construction (private and public) equipment
- The effect of the device upon street sweeping operations
- Potential loss of on-street parking
- Diversion of traffic to other nearby residential local and collector roadways
- Increase in or concentration of noise levels due to the traffic calming device
- Potential changes to community character (street lighting, loss of on-street parking, signage, and roadway surface and alignment)
- Sight distance obstructions related to landscaping, fences, roadway alignment, etc. Appropriate recovery-area spacing between devices
- The proximity to other calmed areas and intersections
- Acceptance of property owners on adjoining and parallel roadways
- Availability of funding for the installation of traffic calming measures
- Timing of proposed improvements with respect to the on-going resurfacing program
TYPICAL TRAFFIC CALMING MEASURES
The following section traffic calming measures outline the different levels of traffic calming and the required approval process for each designated level. These traffic calming measures can be implemented individually or in combination. However, not all measures will be feasible or acceptable in all locations.
This section defines each level in the order of implementation of traffic calming measures. It also serves as a guide in the decision-making process for determining the best possible treatment for specific traffic issues within a community.
Level 1 Traffic Calming:
Requires no physical roadway modifications
Approval authority: Director of Public Works Agency with District supervisor
Level 2 Traffic Calming:
Requires minor physical roadway modifictions
(e.g., raised ceramic tiles, painted legends, striping)
Approval authority: Director of Public Works Agency with District supervisor
Level 3 Traffic Calming:
Requires major physical roadway modifications (e.g., extension of curb lane into roadway, uneven roadway surface)
Approval authority: Director of Public Works Agency with District supervisor
Level 4 Traffic Calming:
Measures physically prohibit vehicular travel to a certain degree (e.g., detours to parallel routes). These are not applicale on collector roadways.
Approval authority: Director of Public Works Agency with District supervisor
Alameda County Traffic Calming Sample Forms
Download the Traffic
Calming Program Packet. (3.62 MB) *
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