To: Honorable Mayor and Members of Town Council
Through: David L. Corliss, Town Manager
Daniel Sailer, Director of Public Works
From: Thomas Reiff, Transportation Planner
Title
Discussion/Direction: Castle Oaks Drive Traffic Calming Request
Body
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Executive Summary
The purpose of this item is to request a formal recommendation from Town Council for the Castle Oaks Drive traffic calming request in the Cobblestone Ranch neighborhood. Homeowners in the area of Castle Oaks Drive near Mentha Drive are requesting the Town to reduce vehicular speed on Castle Oaks Drive through the Neighborhood Traffic Calming Program (NTCP). The procedure to evaluate potential traffic calming measures adheres to the Council approved NTCP from 2023. Speed data was collected in December 2024, and did not show a speeding problem as defined by the NTCP. The recorded 85th percentile speed was 38 miles per hour and the posted speed is 35 mph. The 85th percentile speed is the speed that 85% of people drive at or below at any given location. According to the NTCP, eligible collector streets, such as Castle Oaks Drive should have a traffic volume greater than 1,500 vehicles per day, and the minimum 85th percentile speed should be 5 mph over the posted speed limit. Based on the collected data, staff is recommending no action.
Discussion
In September 2024, homeowners in Cobblestone Ranch provided the Town with a signed petition asking to explore traffic calming measures through the NTCP for Castle Oaks Drive near Mentha Drive to slow traffic. The initial support petition met the Program’s minimum 20 homeowner signatures as required. Town staff then conducted the speed study in December 2024. This information was shared with the neighborhood point of contact along with the policy document.
he following information is from the speed study for Castle Oaks Drive.
Vehicle speeds detected:
• Measured 85th percentile speed: 38 mph
• Measured 90th percentile speed: 40 mph
• Measured 99th percentile speed: 45 mph
Traffic volume:
• Measured average daily traffic volume on the street: 3,867
Attachments B and C show the study area boundary and the location near Mentha Drive where the speed data was collected.
The Town updated the NTCP in 2023 and amended how “collector streets,” such as Castle Oaks Drive are processed. Collector streets generally serve to collect traffic from local streets and take it to nearby arterial streets. They also carry higher traffic volumes and have higher posted speed limits. In this case, Castle Oaks Drive has a posted speed limit of 35 mph. For eligible collector streets the traffic volume should be greater than 1,500 vehicles per day, and the minimum 85th percentile speed should be 5 mph over the posted speed limit. If eligible collector streets do not meet the minimum thresholds, Town Council will still consider the street and be provided with the collected data to assist in making their decision.
Since the measured 85th percentile speed is not 5 mph over the posted speed limit, the traffic calming committee representing multiple departments, including Public Works, Development Services, Castle Rock Police Department, and the Castle Rock Fire and Rescue Department are not recommending traffic calming measures along Castle Oaks Drive at this time.
However, should Town Council decide to proceed with traffic calming, there are several measures or devices that could be considered. These measures include the following:
• A chicane (lateral shift in the roadway),
• Center medians at strategic locations,
• Traffic circles at intersections
• Speed cushion(s), or
• Raised intersection
Attachment A, lists several other options to consider along with potential impacts to the roadway and its users. For example, when utilizing any vertical element (raised crosswalk, raised intersection, etc.), it could increase emergency response times for the homes in this part of Cobblestone Ranch, and the surrounding areas by 6 to 10 seconds depending on the traffic calming device. Additionally, speed cushions, center medians, and chicanes would minimally increase emergency response times. Other factors to take into account is increased noise to homeowners near a raised traffic calming device. Non-engineering options that are available include increased law enforcement, and possible signing and striping changes.
Neighborhood Outreach
If a traffic calming plan is created and recommended, the NTCP process states that staff will reach out to the public for feedback prior to going to Town Council for plan approval. However, the traffic calming committee is recommending no action.
Schedule
If Council approves the no action plan then no additional work is necessary. The street would become eligible for the NTCP in one year.
Budget Impact
There are no anticipated budget impacts with the no action recommendation. Depending on the option directed to pursue, improvements could be up to $100,000 to design and construct.
History of Past Town Council, Boards & Commissions, or Other Discussions
Town Council approved the current NTCP policies in 2023. At the February 3rd Public Works Commission meeting, the Commissioners unanimously recommended Town Council approve staff’s no action plan recommendation.
Recommendation
Staff recommends that Town Council approves the no action plan for Castle Oaks Drive.
Proposed Motions
“I move that Town Council approve the no action traffic calming plan for Castle Oaks Drive as presented by staff.”
Alternative motions:
“I move that Town Council approve the no action traffic calming plan for Castle Oaks Drive, with the following conditions: (list conditions)”
“I move to continue this item to a future Town Council meeting and have Staff develop a traffic calming plan for Castle Oaks Drive.”
Attachments
Attachment A: Possible Traffic Calming Toolbox Measures
Attachment B: Study Area Map
Attachment C: Data Collection Site