To: PUBLIC WORKS AND SUSTAINABILITY COMMISSION
From: DEPARTMENT OF PUBLIC WORKS
TITLE
title
DISCUSSION OF TRAFFIC CALMING MEASURES ON PROSPECT FRONTAGE ROAD (500-600 BLOCK)
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EXECUTIVE SUMMARY
Based on a community meeting and subsequent referral from the District 3 Councilmember, as well as staff’s analysis, staff is bringing forward a discussion of possible traffic calming and access control measures for the frontage road along the 500-600 block of Prospect Avenue. Staff is seeking input on this matter from the public and from the Public Works & Sustainability Commission (PWSC). Noticing for this item was provided to the residents living along the 500-600 frontage road of Prospect.
ANALYSIS
In December 2024, the District 3 Councilmember held a neighborhood meeting with residents living along the 500-600 block of Prospect Avenue regarding traffic speed/safety, noise, and aesthetic concerns. This included:
• Speeding, traffic safety, and cut-through traffic concerns along the frontage road
• Speeding and safety concerns along mainline Prospect Avenue
• Ambulance siren noise, possibly associated with Beach Cities Health District (BCHD)
• Visual and noise issues due to frontage median shrub deterioration (drought and disease)
• Desire for protective measures to mitigate the potential for errant driver departures from mainline to frontage Prospect
This agenda item is primarily focused on traffic-related issues, as Public Works Operations staff have been addressing the landscaping issues. Sample plantings have been installed, and a Budget Response Report is being prepared for the Council regarding a sound wall or other barrier options. The study area is the frontage road along southbound Prospect, which starts just south of Beryl Street and ends at Diamond Street. The frontage road provides two-way travel between just south of Beryl and the BCHD entrance intersection, although the road is not wide enough for unimpeded two-way travel. Frequent driveways and low parking utilization prevent such conflicts from occurring frequently. South of BCHD intersection, the frontage road is one-way northerly between Diamond and BCHD. The opening at BCHD provides signalized ingress and egress onto mainline Prospect. The 1,000-foot-long frontage road is classified as a residential street with a 25-mph residential prima facie speed limit and a street grade of less than 8%. Attachment 1 shows an overview of the area. At the neighborhood meeting in December, staff presented traffic speed and volume data for mainline Prospect between Beryl and Del Amo, which showed an average daily traffic of 16,000 vehicles per day and 42 mph 85th percentile speeds. Staff explained that the most impactful countermeasures for traffic calming on mainline Prospect would require Council direction and further study.
Speed Cushions
After the neighborhood meeting, the District 3 Councilmember and staff provided the City’s Speed Cushion Policy and materials to the residents, who proceeded to gather signatures in order for City staff to study installation of speed cushions on the frontage road. The process to approve and install speed cushions is based on City Council policy. Resident petitioners are required to seek approval of at least two-thirds of residents on the affected block by reading and signing the City’s standard signature form for these types of requests. Only one vote per dwelling unit is allowed and signatures are spot verified for residency against City records. Under the City’s policy and procedures, signatures received outside of the surveyed street segment are not considered as part of the official approval process. Only after sufficient resident support is reached does the City proceed with further technical study. In January 2025, staff received and verified support from 18 of the 27 residences along the subject block. Therefore, City staff deemed this step of the process complete.
The City has a list of technically based installation criteria for speed cushions, which includes street classification, grades, horizontal alignment, speed limit, surveyed 85th percentile speed, and traffic volumes, shown in Attachment 2. While staff deemed most technical criteria were met, speed and volume data collected in February 2025 shows that this block does not meet speed thresholds for speed cushion per City policy. The City’s policy threshold for speed cushions requires an average two-way 85th percentile speed of 32 mph. Speeds were collected at 515 and 603 N Prospect, which are representative of the highest likely speeds along the frontage road. The 85th percentile speeds of 22 and 24 mph were recorded, substantially below the thresholds. Attachment 3 shows the speed and volume summary for the frontage road.
Therefore, staff is not able to recommend the installation of speed cushions along the 500-600 Prospect frontage road per current City policy. Staff would like to note that reaching this outcome during this process is not unusual. Within the past 12 months, staff have encountered this situation twice where the resident support threshold was met but the speed threshold was not met. Typically, cases like this stop at the staff level and do not reach the PWSC for consideration. The data and staff’s evaluation were provided to the residents and the District 3 Councilmember, who referred the speed cushion analysis to the PWSC for discussion and consideration along with other traffic calming solutions. Despite the engineering thresholds not being met, staff does not oppose an installation along the frontage road on technical grounds since the only drivers likely to be significantly impacted are those who live on the block, and their visitors. When speed thresholds are met, speed cushions should be placed at regular and predictable intervals to prevent undesired acceleration. Attachment 4 shows potential locations from an engineering perspective, if it is decided to advance with the speed cushions on the frontage road.
Frontage Road Access
Another potentially feasible traffic calming solution in this area would be to remove inbound access to the frontage road at the BCHD intersection. Because the frontage road is narrow, there may not be enough space to accommodate both queued outbound vehicles and drivers making inbound maneuvers. Reducing possible turning maneuvers at intersections is a common way to reduce the potential for conflicts, especially when street width is limited. Staff proposes a 3-month trial to close inbound access into the frontage road at the BCHD traffic signal. This type of closure would be easy to implement with water-filled barricades and signage. It would involve closing the northbound left-turn lane from mainline Prospect, bagging the left-turn signal heads, closing the inbound opening adjacent to the median, and installing appropriate signage. This would leave the area around the BCHD and frontage road intersection solely for frontage road through traffic or egress. Attachment 5 shows how this trial closure could work. Inbound access into the frontage road would still be preserved via the north end of the block or from the south end at Diamond. If successful and supported, a fully funded CIP project would be required to permanentize the closure.
Attachment 6 shows public comment received after notice of this agenda item was mailed.
COORDINATION
Coordination of this report took place within the Public Works Department.
ATTACHMENTS
1 - Overview Map
2 - Speed Cushion Policy
3 - Speed and Volume Summary (500-600 Prospect Frontage)
4 - Possible Speed Cushion Locations
5 - Trial Closure (Inbound Frontage Road Access at BCHD)
6 - Public Comment