City Council Memorandum
TO: HONORABLE MAYOR AND CITY COUNCIL DATE: MAY 20, 2025 FROM: PUBLIC WORKS DEPARTMENT WARDS: 4
SUBJECT: REQUEST FOR SPEED HUMPS ON KILMARNOCK WAY
ISSUE:
Consider implementation of speed humps along Kilmarnock Way between Kelty Drive and Barton Street.
RECOMMENDATION:
That the City Council approve the proposed speed humps on Kilmarnock Way between Kelty Drive and Barton Street in support of the Transportation Board’s recommendation.
BOARD RECOMMENDATION:
On April 2, 2025, the Transportation Board (Board) reviewed this matter; six of six members were present. Staff recommended denial of the speed humps based on established criteria, however, the denial was appealed by residents of Kilmarnock Way. After a thorough discussion, the Board ultimately voted unanimously to recommend approval of the proposed speed humps along Kilmarnock Way between Kelty Drive and Barton Street.
BACKGROUND:
The Neighborhood Traffic Management Program (NTMP) was designed to provide general guidelines for the assessment of traffic issues on local, collector, and arterial roadways throughout the City as well as outline various traffic mitigation measures which may serve as suitable solutions to demonstrated traffic issues.
As part of the Neighborhood Traffic Management Program (NTMP), the city re-instated a formal Speed Hump Policy Guidelines and Procedure on May 7, 2024, to effectively address concerns related to speeding on residential streets. The goal of this policy is to enhance neighborhood safety by implementing traffic calming measures, such as speed humps, to reduce vehicle speeds on eligible residential streets. This policy aims to unite neighborhoods and identify appropriate measures to improve travel behavior for the benefit of affected communities. Speed humps are a potential secondary option for residential designated streets. A website outlining details of the Speed Hump Program has been developed – Speed Hump Program | Public Works A speed hump is an elongated mound in the roadway pavement surface extending across the traveled way designed perpendicular to the traffic flow. The purpose of a speed hump is to regulate traffic speeds by providing minor vertical deflection while driving through it. Speed humps are still considered experimental roadway features; therefore, additions, alterations, or removals of all speed humps may occur at any time.
DISCUSSION:
The city received a petition from the residents on Kilmarnock Way requesting speed humps to be installed on their street. The petition and roadway conditions on Kilmarnock Way between Kelty Drive and Barton Street (Attachment 1 – Location Map) were reviewed for consistency with the City’s Speed Hump Program. The petition reflects that 41 of the 46 residents (89%) on Kilmarnock Way support speed humps, which meets the minimum requirement of 70%. There were no signatures from residents opposing the consideration of speed humps. Staff investigated speeds, volumes, and street geometrics. Comparing staff’s investigation of Kilmarnock Way with the City’s set guidelines for speed humps resulted in 6 out of 8 criteria being met. Based on the requirement to meet all 8 criteria, Kilmarnock Way does not qualify for speed humps per the approved policy. A summary of the findings is provided on Attachment 2 and staff have provided all this information to the Kilmarnock Way residents. However, a letter of appeal (Attachment 10) was submitted to staff requesting that the Transportation Board consider the speed hump request.
Because the roadway does not meet the established criteria for speed hump installation and staff are not aware of mitigating circumstances that would merit overriding the established criteria, staff recommend denial of the appeal to the Transportation Board at the April 2, 2025. The preliminary cost estimate of the speed humps is $21,480. However, the Transportation Board recommended approval of the speed humps to the City Council upon receiving six e-comments and three in-person meeting comments in support of the speed humps. One e-comment opposed the speed hump installation. Due to the overwhelming support and the majority of the criteria being met, the Public Works Department is supportive of the request.
Kilmarnock Way is a two-way (one lane in each direction) collector street located between Barton Street to the east, and Kelty Drive to the west. It is approximately 1,440 feet in length and 36 feet wide, which meets the minimum required length of ¼ mile (1,320) and does not exceed the maximum width of 40 feet. There are 46 homes on both sides of the street meeting the minimum requirement of sixteen (16) homes for a double-loaded street. Attachment 3 illustrates the potential speed hump locations along Kilmarnock Way. There are three (3) speed humps shown.
There were two speed surveys and traffic counts conducted on Kilmarnock Way as part of staff’s investigation. The radar surveys measured the 85th percentile speed in the range of 28mph to 33 mph on Kilmarnock Way which does not meet the 37-mph minimum required by the city program. The corresponding 24-hour two-way volume counts indicated total daily volumes in the range of 594 to 729 vehicles per day, which does not meet the minimum threshold of 750 vehicles per day. The estimated vertical grade is in the range of 1.6%-2.98% along Kilmarnock Way which is below the maximum eight (8) percent vertical grade threshold. Several photos of Kilmarnock Way are included in Attachment 5. Despite all the previously utilized speed management alternatives, vehicular speeding continues to persist with an 85th percentile speed in the range of 28MPH-33 MPH (3MPH-8 MPH over the prima facie speed limit of 25 MPH).
The Riverside Fire Department has provided a general comment regarding proposed speed humps in consideration of potential impacts to emergency response times, if any. The RFD has requested the city to consider installing a Speed Bump (Type II) of Standard Plan 257 for new speed hump installations. The Type II Speed Bump has gaps in the middle to allow emergency vehicles to bypass speed humps on the roadway during an urgent emergency call. Golden Avenue between Pierce Street and Cypress Avenue currently has Type II Speed Bumps installed and there have not been any concerns with its utilization.
Staff has prepared an exhibit showing potential locations for the installation of speed humps. The locations are selected based on having adequate spacing between curves and intersections and adequate sight distance to allow for proper signing on each approach. Utility covers and driveways in the street are also avoided. Staff selected locations where signs may be placed on existing poles or streetlights to minimize the impacts of the signs on the neighborhood. A total of three (3) potential locations were found for speed humps. Each speed hump installed would potentially add an additional delay of 10 (ten) seconds to emergency vehicles. However, the usage of the Type II Speed Bumps would significantly minimize if not eliminate delays for emergency vehicles.
A review of our traffic accident records for the past three years on Kilmarnock Way from 2022 through 2024 shows zero reported traffic collisions. There were no speed related collisions.
The City’s Speed Hump Policies, Guidelines, and Procedures are included in Attachment 6. Attachment 7 illustrates the City’s Standard Plan Detail No. 251 – Speed Bump (Type II).
The Institute of Transportation Engineers (ITE) has also published some Guidelines for the Design and Application of Speed Humps. One of the guidelines worth mentioning from the ITE guidelines is the spacing for speed humps (see Attachment 8). The exhibit displays a properly designed speed hump spacing in the range of 150–500-foot space on each side prior to the speed hump.
The Federal Highway Administration (FHWA) Engineering Speed Management Countermeasures offers an excellent resource for speed humps studies and resulting speed reduction effectiveness (Attachment 9). As documented, speed humps can be effective at reducing speeds in the range of 5-13 mph.
Conclusion:
Kilmarnock Way meets 6 of the 8 criteria of the City’s adopted policy for speed humps. It does not meet the minimum average daily traffic (ADT) threshold of 750 vehicles per day. The observed ADT was 729 vehicles, the observed 85th percentile speed was 33 mph not meeting the minimum speed of 37 mph. Based on the requirement to meet all 8 criteria, Kilmarnock Way does not qualify for speed humps per the City approved policy. A summary of the findings is provided via Attachment 2 and staff has provided this information to the residents on Kilmarnock Way. However, a letter of appeal (Attachment 10) was submitted to city staff requesting for proposed speed humps to be reviewed by the Transportation Board. If speeds humps are approved, then there is a potential to add three (3) speed humps as shown in Attachment 3. If speed humps are not approved, traffic calming measures can be considered including posted speed limit signs, stop ahead signage & striping, centerline striping, and / or spot police enforcement.
STRATEGIC PLAN ALIGNMENT:
The proposed speed humps on Kilmarnock Way align with Strategic Priority 2 – Community Well-Being and Goal 2.4 - Support programs and innovations that enhance community safety, encourage neighborhood engagement, and build public trust.
This item aligns with each of the five Cross Cutting Threads as follows:
Community Trust – As part of the Neighborhood Traffic Management Program (NTMP), the Speed Hump Program establishes community Trust through the transparent methodology and public process set forth at multiple public meetings. The proposed speed humps are based on engineering judgement, cited benefits, and public interest.
Equity – The Speed Hump Program provides safe usage of the public right of way for all roadway users including vehicles, bicycles, and pedestrians. Proposed restoration of the use of speed humps as a secondary mitigation measure option under the NTMP for local 25 MPH streets and the qualifying criteria apply to all eligible neighborhoods and street segments.
Fiscal Responsibility – The proposed speed humps technical qualifying criteria will aid in reducing potential annual project costs by targeting 25 MPH local streets experiencing both high traffic volumes and substantial speeding to provide a traffic calming and increase safety at the most impacted locations.
Innovation – The proposed Speed Bump (Type II) design will create gaps on each speed hump which minimizes, if not eliminate, impacts to emergency response times for emergency vehicles.
Sustainability & Resiliency – The use of speed humps as part of the NTMP will provide another potential traffic calming tool to reduce speeding and increase safety in residential neighborhoods. Speed humps serve as a sustainable, lasting, and physical deterrent to vehicle speeding.
FISCAL IMPACT:
If the proposed speed humps are recommended for approval by City Council, then the fiscal impact of this action for the cost of installation of speed humps, signage and pavement markings is estimated at $21,480. Funding is budgeted and available in the Measure A Fund, Speed Hump Traffic Calming Project account number 9927230-440313, to cover this cost.
Prepared by: Philip Nitollama, City Traffic Engineer
Approved by: Gilbert Hernandez, Public Works Director
Certified as to
availability of funds: Kristie Thomas, Finance Director/Assistant Chief Financial Officer Approved by: Kris Martinez, Assistant City Manager
Approved as to form: Rebecca McKee-Reimbold, Interim City Attorney Attachments:
Location Map
Speed Hump Criteria Checklist
Potential Locations
Traffic Count Data
Street View Photos
Speed Hump Program Policies, Procedures, and Guidelines Standard Plan No. 251 – Speed Bump (Type II)
Speed Hump Spacing Exhibit from ITE Speed Hump Guidelines FHWA Engineering Speed Management Countermeasures – Speed Humps Appeal Letter
Presentation
Transportation Board Meeting Minutes – April 2, 2025
Kilmarnock Way Proposed Speed Humps ● Page 2