To: PUBLIC WORKS AND SUSTAINABILITY COMMISSION
From: DEPARTMENT OF PUBLIC WORKS
TITLE
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DISCUSSION OF TRAFFIC CALMING MEASURES AT FLAGLER/CLARK INTERSECTION
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EXECUTIVE SUMMARY
The City received a request for an all-way stop (AWS) from a local homebuilder at the Flagler Lane and Clark Lane intersection to address speeding concerns along Flagler, which is currently stop-controlled for the one-way eastbound Clark approach. The request was not initiated by a current resident. City staff is exploring other engineering countermeasures besides stop signs when conditions allow, especially since AWS are not appropriate for speed control per the CAMUTCD. Staff discussed the Flagler/Clark intersection with the District 4 Councilmember, who provided direction to explore median treatments at this intersection to address excessive speeds. Staff is seeking input from the PWSC and the public. Noticing was provided to the residents living within 150 feet of Flagler/Clark.
BACKGROUND
In February 2025, staff and the District 4 Councilmember received a request from a local homebuilder who is redeveloping a residential lot at the corner of Flagler/Clark. The homebuilder is concerned that future residents would have difficulty backing out of driveways onto Flagler due to traffic speeds on Flagler. Staff would like to note that Flagler is the same width as other residential streets in the area, but does not contain street parking on either side. While this improves driveway exiting visibility compared to most streets in the area, the lack of parked cars encourages higher driving speeds due to wider lanes. The homebuilder requested stop signs on Flagler to address speeding. According to CAMUTCD Section 2B.04.05, yield or stop signs should not be solely used for speed control. Therefore, staff proposed that data should be collected and alternative traffic calming measures should be explored before considering an all-way stop per the City’s AWS Policy. The councilmember was in support of this plan of action.
ANALYSIS
Engineers from the City visited the Flagler/Clark intersection to determine if there are any visibility issues that could warrant an AWS. Staff observed no visibility issues on the eastbound Clark approach that would require Flagler traffic to stop in order to proceed safely through the intersection. Staff also performed a collision analysis and found two (2) collisions within the past five years that could be corrected by either traffic calming measures or an AWS. Note that the visibility and collision data does not meet typical AWS thresholds found in the City’s AWS Policy or the CAMUTCD.
Staff then collected traffic data at Flagler/Clark, which includes 24-hour/7 days of speed and volume data along Flagler north of Clark, and 24-hours of volume data along Clark west of Flagler. Data was collected in February/March of 2025, and can be found in Attachment 1. 85th percentile speeds along Flagler were 30 mph. While this is above the 25 mph speed limit, they are not considered excessive enough to install speed bumps/cushions per City policy thresholds. An average of 2,671 vehicles traveled along Flagler, which is higher than typical residential streets since Flagler connects with 190th St and Beryl St. Traffic volumes show that only 11-12% of the intersection’s traffic originates from Clark. Therefore, it would be inappropriate to force 88% of traffic to stop for very little cross traffic.
Because the reported collisions, visibility analysis, and traffic volumes do not meet typical City or State/Federal policy thresholds, an AWS is not recommended at this intersection. To control excessive speeding, staff proposes to install short medians at this intersection to slow down drivers. This is possible because Flagler does not allow parking on either side of the street, and medians would force drivers on Flagler to slow down and shift laterally to the right to proceed. Medians on the north and south legs would narrow the approach lanes to approximately 10-11 feet. The medians would also serve as a de facto pedestrian refuge island, and would not conflict with turning movements or driveways. These treatments are common in other cities. Attachment 2 shows two median treatment alternatives, both of which offer effective countermeasures to excessive speed by narrowing the lanes near the intersection. The first alternative installs 8-inch diameter raised/reflective pavement markers. These pavement markers are faster and cheaper to install, and do not require drilling holes in the pavement. They are also traversable and are felt by drivers like a speed bump. Similar treatments were installed at Harkness/Agate and Del Amo/Paulina. The second option installs a 6.5-foot-wide modular prefabricated median that requires drilling holes in the pavement. This treatment may be more visible than the first option and provides full height curb. However, a modular median is more costly to install and maintain. The City will install a similar median at Beryl/Guadalupe as a trial but has not determined such treatment to be a sustainable standard at this time.
Given the finite resources of the City for traffic calming improvements, staff is seeking input from the Commission and public as to whether to install a median treatment at this location. If the Commission so recommends, staff will then determine which treatment is selected based on cost, availability and availability of crew to install.
COORDINATION
Coordination of this report took place within the Public Works Department.
ATTACHMENTS
1 - Flagler/Clark Speed & Volume Data
2 - Flagler/Clark Median Options