AGENDA PACKET
Town of Atherton
City Council
SEPTEMBER 04, 2024
SPECIAL MEETING – STUDY SESSION
4:00 PM
Council Chambers
80 Fair Oaks Lane
Atherton, CA 94027
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SPECIAL MEETING STUDY SESSION
ROLL CALL – Holland, DeGolia, Widmer, Vice Mayor Lewis , Mayor HawkinsManuelian PUBLIC COMMENT – Public Comments can be emailed directly to [email protected]
As a special meeting, public comment is limited to items on the agenda. Speakers’s time is limited to three minutes. Speakers may also speak when the item is discussed during the meeting.
ACTION ITEMS
STUDY SESSION
1. RECEIVE AN UPDATE AND PROVIDE FEEDBACK ON THE ALAMEDA DE LAS PULGAS / ATHERTON AVENUE ROUNDABOUT ANALYSIS
Report: ROBERT OVADIA, PUBLIC WORKS DIRECTOR
Recommendation: It is recommended that the Council provide feedback and direction regarding the feasibility analysis of a roundabout on Alameda de las Pulgas at Atherton Avenue.
Description: This item involves Council feedback and direction on whether a roundabout on Alameda de las Pulgas at Atherton Avenue is feasible.
2. DIRECTION AND FEEDBACK REGARDING TRAFFIC STUDIES AND
RECOMMENDATIONS
Report: ROBERT OVADIA, PUBLIC WORKS DIRECTOR
Recommendation: It is recommended that the Council review and provide feedback and direction to staff regarding prioritization of traffic improvements.
Meeting Agenda Packet – September 04, 2024
PULGAS / ATHERTON AVENUE ROUNDABOUT ANALYSIS
Report: ROBERT OVADIA, PUBLIC WORKS DIRECTOR
Recommendation: It is recommended that the Council provide feedback and direction regarding the feasibility analysis of a roundabout on Alameda de las Pulgas at Atherton Avenue.
Description: This item involves Council feedback and direction on whether a roundabout on Alameda de las Pulgas at Atherton Avenue is feasible.
2. DIRECTION AND FEEDBACK REGARDING TRAFFIC STUDIES AND
RECOMMENDATIONS
Report: ROBERT OVADIA, PUBLIC WORKS DIRECTOR
Recommendation: It is recommended that the Council review and provide feedback and direction to staff regarding prioritization of traffic improvements.
Description: This item involves Council review and direction to staff on how to prioritize traffic improvements.
COUNCIL REPORTS/COMMENTS
ADJOURN
PLEASE NOTE THE FOLLOWING INFORMATION:
If you challenge a Town zoning, planning, or any other decision in court, you may be limited to raising only those issues you or someone else raised at the public hearing described in this agenda, or in written correspondence delivered to the Town at, or prior to, the public hearing. Judicial review of any Town administrative decision may be had only if a petition is filed with the court not later than the 90th day following the date upon which the decision becomes final. Judicial review of environmental determinations may be subject to a shorter time period.
Copies of all staff reports and documents subject to disclosure that relate to each item of business referred to on the agenda are available for public inspection by 5:00 p.m. the Friday before each regularly scheduled City Council meeting.
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The Town of Atherton Council and Committee or Commission meetings are a limited public forum, and all public comment must relate to something that is within the subject matter jurisdiction of the Council or Committees. If comments do not relate to the subject matter jurisdiction of the Council or Committee, we will stop the comment and a warning may be provided. If the comment continues to be outside of the subject matter jurisdiction the speaker will be stopped, and we will move on to the next speaker. Speakers found in violation of this rule of procedure may be removed from the meeting.
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No person participating in a public meeting shall engage in disorderly or boisterous conduct — including but not limited to applause, whistling, feet stamping, booing or making any loud, threatening, profane, abusive, personal, impertinent or slanderous uttering or Meeting Agenda Packet – September 04, 2024
The Town of Atherton Council and Committee or Commission meetings are a limited public forum, and all public comment must relate to something that is within the subject matter jurisdiction of the Council or Committees. If comments do not relate to the subject matter jurisdiction of the Council or Committee, we will stop the comment and a warning may be provided. If the comment continues to be outside of the subject matter jurisdiction the speaker will be stopped, and we will move on to the next speaker. Speakers found in violation of this rule of procedure may be removed from the meeting.
Rules of Decorum:
No person participating in a public meeting shall engage in disorderly or boisterous conduct — including but not limited to applause, whistling, feet stamping, booing or making any loud, threatening, profane, abusive, personal, impertinent or slanderous uttering or comments. No person is allowed to disturb, disrupt, or otherwise impede the orderly conduct of the meeting.
If any person continues to breach the Rules of Decorum in a manner that disturbs, disrupts or otherwise impedes the orderly conduct of the meeting following an order from the Mayor, or Presiding Officer, to cease the offending conduct, the Mayor, or Presiding Officer, may order that person to leave the meeting.
Meeting Agenda Packet – September 04, 2024
Item No. 1
Town of Atherton
CITY COUNCIL STAFF REPORT – STUDY SESSION
TO: HONORABLE MAYOR AND CITY COUNCIL
GEORGE RODERICKS, CITY MANAGER
FROM: ROBERT OVADIA, PUBLIC WORKS DIRECTOR
DATE: SEPTEMBER 4, 2024
SUBJECT: RECEIVE AN UPDATE AND PROVIDE FEEDBACK ON THE
ALAMEDA DE LAS PULGAS / ATHERTON AVENUE
ROUNDABOUT ANALYSIS
RECOMMENDATION
It is recommended that the Council provide feedback and direction regarding the feasibility analysis of a roundabout on Alameda de las Pulgas at Atherton Avenue.
BACKGROUND
The Alameda de las Pulgas corridor which connects Redwood City to Menlo Park and Palo Alto, through the Town of Atherton, and unincorporated San Mateo County is a high traffic corridor that serves as a north-south alternate to El Camino Real. Pass-through traffic has been measured to be between 60% to 89% of the overall traffic volume. Residential streets are impacted as commuters attempt to find alternative routes around congested roadways during peak hours, particularly around the Atherton Avenue intersection which is four-way stop controlled.
The Alameda de las Pulgas corridor was evaluated in two separate studies in 2019. The Alameda de las Pulgas Corridor Traffic Study reviewed existing conditions along Alameda de las Pulgas and recommended several improvements, both within and outside of Town limits. The Local Traffic Flow/Long Range Planning Solutions Study evaluated existing traffic operations and origin-designation patterns and recommended short- and long-term measures for efficient circulation. Additionally, it has been determined through these studies that the all-way stop intersection of Atherton Ave and ADLP currently operates at a level of service (LOS) F with delays up to 92 seconds during the peak hours and that signalizing this intersection will improve operations to LOS B with projected delays less than 18 seconds.
The corridor study also advised that a roundabout at the Atherton Avenue intersection would also significantly reduce vehicle delays. Though a full analysis was not completed at the time, in consideration of the limited right-of-way at the intersection, the study recommended the
ADLP/Atherton Avenue Roundabout Analysis
SEPTEMBER 4, 2024
installation of a traffic signal rather than a roundabout at the intersection.
Following City Council discussion at its March 6, 2024, meeting, staff issued a task order to Interwest Consulting Group (Interwest) to evaluate the feasibility of a traffic circle, roundabout or mini-roundabout at the Alameda de las Pulgas / Atherton Avenue intersection.
ANALYSIS
In evaluating the feasibility of a potential roundabout, Interwest reviewed existing conditions, accident history, level of service and various design considerations.
Existing conditions:
• Alameda de las Pulgas is a minor arterial with a speed limit of 30 miles per hour, features a Class II bikeway (dedicated bike lanes), is served by two bus stops on the north leg of the intersection, and has various utilities located in and around the intersection. o It is noted that the Alameda Traffic and Safety Improvements Project will adjust lane widths and bicycle lane configuration along the Alameda de las Pulgas corridor.
• Atherton Avenue is a local collector street, with a speed limit of 30 miles per hour east of the Alameda de las Pulgas intersection and 25 miles per hour to the west of the intersection.
The roadway is currently marked as a Class III (shared use) bikeway east of the intersection, with a designation as a future Class II facility (dedicated bike lanes) in the bicycle and pedestrian master plan.
Collision History:
• Two collisions were noted at the intersection between January 1, 2019, and December 31, 2023. One, in May 2022, located approximately 60 feet south of the intersection, involved a bicycle and a vehicle and resulted in suspected minor/visible injury. The other collision involved a vehicle with object. Both collisions were determined to be related to speeding.
Traffic Analysis:
• The intersection is currently stop controlled.
• Per the Alameda de las Pulgas Corridor Study, prepared by AMG, the current Level of Service (LOS) is at F, with delays of approximately 1.5 minutes southbound in the morning peak and northbound in the afternoon peak. The study concludes that the implementation of a roundabout, or traffic signal would significantly reduce vehicle delays and improve the Level of Service at the intersection.
Findings:
Interwest reviewed various alternatives for the roundabout and concluded that, if a roundabout is to be implemented, a single-lane roundabout with a non-traversable central island (with truck apron), raised splitter islands, mixed use pathways and separated pedestrian crossings would be most appropriate. Raised truck aprons are proposed to be provided to accommodate turning movements of larger trucks and emergency vehicles. An illustration of a standard configuration is shown in Attachment 1.
ADLP/Atherton Avenue Roundabout Analysis
SEPTEMBER 4, 2024
Interwest recommends the following for the layout of the roundabout:
• Inscribed diameter of traffic lane (outside edge to outside edge) = 90 feet • Travel lane width (within the roundabout) = 12 feet
• Truck apron width (to accommodate truck and emergency vehicle turn movements) = 15 feet
• Truck apron height = 3-inches, with rolled curb
• Raised splitter islands to separate traffic and provide pedestrian refuges for street crossings • Mixed uses pathway (10 feet wide minimum), with ramps to and from bike lanes, around each corner
The analysis also identifies several constraints as follows:
• Right-of-way/property acquisition – the conceptual design shows that a roundabout can be accommodated at the intersection with nominal acquisition, predominantly at the northwest and southeast corners. Interwest believes that the need for right-of-way can be reduced or eliminated with minor adjustments in the layout during the design process by slightly changing the shape of the roundabout, making it a little more oval in shape. • Major utility conflicts – in addition to some minor utility adjustments, there a couple of significant utility conflicts that will require significant coordination and resources to accomplish. These include:
o Electrical transmission pole relocation (northwest corner) o Communications infrastructure relocation (southeast corner) • Bus stops – there are two bus stops located north of the intersection that will need to be considered in the final design
• Drainage system – drainage system modifications in the intersection will be needed to align with the reconfiguration of the intersection and to coordinate with green infrastructure improvements
• Environmental impacts and considerations – The Town is currently working with Caltrans regarding potential impacts of the Alameda de las Pulgas Corridor Traffic and Safety Improvements Project. Concerns have been raised regarding potential impacts to cultural resources associated with the proposed traffic signal and intersection reconfiguration. The environmental review is still pending. The potential impacts associated with the increased footprint of the roundabout would need to be analyzed.
• Costs – the preliminary cost estimate for the roundabout is quite a bit higher than the estimated cost of the traffic signal installation, approximately $500,000, not including design costs.
The implementation of a roundabout would have several additional impacts that were not included in the analysis. These include, but are not limited to:
• Additional stormwater treatment/green infrastructure areas required along Alameda de las Pulgas and in the area of the intersection to accommodate regulatory requirements associated with the creation and replacement of impervious areas. • Though property acquisition may be reduced/eliminated through final design, there will be impacts to property frontages and frontage improvements associated with the roadway realignment and widening required to implement the roundabout.
ADLP/Atherton Avenue Roundabout Analysis
SEPTEMBER 4, 2024
• Access impacts – the implementation of the roundabout would also impact driveway access. The splitter islands (raised and marked) would restrict left turns in and out of driveways along both Atherton Avenue and Alameda de las Pulgas. • Noise impacts – noise impacts are anticipated at the intersection related to truck movements as they traverse the roundabout and truck apron.
• Lighting impacts – It is recommended that the Town consider the installation of streetlights to improve visibility of pedestrians crossing the street. Installation of Rectangular Rapid Flashing Beacons (RRFB’s) may also be considered to further advise traffic of pedestrians crossing the street.
• Grant Impacts – The grant received for the Alameda de las Pulgas Traffic and Safety Improvement project requires obligation of federal funds for construction by Fall 2025.
The current project schedule forecasts construction beginning in summer 2025, in advance of the obligation deadline. It is unclear if the grant would cover the roundabout as the initial project description included a traffic signal at the intersection. Further, the implementation of the roundabout will require environmental, right-of-way and utility clearance and certification by Caltrans in advance of requesting obligation of construction funding. This will further extend the timeline of the project. Coordination is required with both AT &T and PG&E to facilitate relocation of utility infrastructure. The process and timelines associated with utility relocations, particularly with PG&E is not timely. It is noted that a power connection would be required from PG&E for the traffic signal alternative.
Public engagement:
• Outreach letters – Prior to initiating the evaluation of the roundabout, the Town sent letters to the properties directly adjacent to the intersection to gauge interest and concerns regarding the potential roundabout. Two property owners reached out via phone after receiving the letter. One resident, though supportive of roundabouts in general, was opposed to a roundabout in this location. The other resident did not respond after several attempts at contacting.
• Public outreach meeting – a public outreach meeting associated with the Alameda de las Pulgas Traffic and Safety improvements project was held on June 20, 2024, to review the conceptual design of the project. Approximately 12 members of the public attended the meeting. The conceptual design outlined proposed improvements along the corridor including lane width reductions and modifications to allow for buffered bike lanes, as well as traffic signals at the Camino al Lago and Atherton Avenue intersections. Additionally, attendees were advised that we were also evaluating the possibility of a roundabout at the Atherton Avenue intersection. Two residents expressed opposition to a traffic signal at the Atherton Avenue intersection and asked what problem we were solving as they did not see a significant issue at the intersection. They were more supportive of the idea of a roundabout than a signal at the location.
• The conceptual design for the Alameda de las Pulgas Traffic and Safety Improvements, along with the conceptual roundabout layout, were also presented to the Transportation, Bicycle and Pedestrian Safety Committee. The Committee was supportive of the roundabout concept.
• Public education may be needed regarding roundabouts and how to navigate.
ADLP/Atherton Avenue Roundabout Analysis
SEPTEMBER 4, 2024
FISCAL IMPACT
None at this time. Additional costs will be incurred for the design and construction of the roundabout. Should the Council desire to pursue the design of the roundabout, staff will seek guidance from Caltrans regarding the potential and process for revising the scope of the grant to allow for a roundabout at the intersection.
GOAL ALIGNMENT
This Report and its contents are in alignment with the following Council Policy Goals:
• Goal Area A – Maintain Fiscal Responsibility
• Goal Area B – Preserve Small Town Character and Quality of Life • Goal Area D – Manage Circulation and Improve Safety
• Goal Area F – Be Forward-Thinking, Well-Managed, and Well-Planned
POLICY FOCUS
The Council policy focus should be on the desire to improve public, pedestrian, and bicycle safety, and traffic flow along the Alameda de las Pulgas corridor. In addition, the Council will need to consider impacts on grant funding, locally required funding, and project timing.
PUBLIC NOTICE
Public notification was achieved by posting the agenda, with this agenda item being listed, at least 72 hours prior to the meeting in print and electronically. Information about the project is also disseminated via the Town’s electronic News Flash and Atherton Online. There are approximately 1,200 subscribers to the Town’s electronic News Flash publications. Subscribers include residents as well as stakeholders –to include, but be not limited to, media outlets, school districts, Menlo Park Fire Protection District, service provides (water, power, and sewer), and regional elected officials.
COMMISSION/COMMITTEE FEEDBACK/REFERRAL
This item has not been before a Town Committee or Commission
ATTACHMENTS
1. Roundabout Feasibility Report
2. Utility and right-of-way photos
3. Conceptual layout of the traffic signal option
Alameda de las Pulgas and Atherton Avenue
Roundabout Feasibility Report
Prepared for:
Town of Atherton
80 Fair Oaks Ln
Atherton, CA 94027
Prepared by:
Interwest Consulting Group, Inc.
9300 W. Stockton Blvd, Suite 105
Elk Grove, CA 95758
(Final) August 13, 2024
Table of Contents
Executive Summary ...................................................................................................................................................4 Introduction ...............................................................................................................................................................4 Existing Conditions ....................................................................................................................................................5 Collision History Data ............................................................................................................................................5 Traffic Counts .........................................................................................................................................................6 Level of Service ......................................................................................................................................................6 Design Alternatives ....................................................................................................................................................7
1. Traffic Signal Alternative ...................................................................................................................................7
2. Neighborhood Traffic Circle Alternative ...........................................................................................................7
3. Roundabout Alternative ....................................................................................................................................7 Roundabout Alternative Approach ......................................................................................................................... 10 Design Considerations ......................................................................................................................................... 10 Coordination and Relocation Items .................................................................................................................... 12 Property Right-of-Way Acquisitions .................................................................................................................... 12 Schedule .............................................................................................................................................................. 13 Preliminary Cost Estimate ................................................................................................................................... 14 Education ............................................................................................................................................................. 15 Safety ................................................................................................................................................................... 15 Environmental Review ............................................................................................................................................. 15 Conclusion ............................................................................................................................................................... 16 References ................................................................................................................................................................ 17 Appendix .................................................................................................................................................................. 18 Appendix A - San Mateo County GIS property map for intersection of Alameda de las Pulgas and Atherton Avenue .................................................................................................................................................... 19 Appendix B - Preliminary Cost Estimate ........................................................................................................ 20
List of Figures
Figure 1: Intersection of Alameda de las Pulgas and Atherton Avenue. .................................................................5 Figure 2: Turning Movement Volumes. ....................................................................................................................6 Figure 3: Roundabout Alternative Concept. ............................................................................................................9 Figure 4: Intersection Conflict Points. .................................................................................................................... 15 List of Tables
Table 1: Intersection of ADLP and Atherton Avenue Level of Service (LOS) – Existing Conditions. .......................6 Table 2: Intersection of ADLP and Atherton Avenue Level of Service (LOS) – Design Alternatives. .......................6 Table 3: Comparison of Common Roundabout Features Across Types of Roundabouts. .....................................8 Table 4: Relocation Items. ...................................................................................................................................... 12 Table 5: Roundabout Schedule. ............................................................................................................................. 13 Table 6: Roundabout Alternative Preliminary Cost Estimate. .............................................................................. 14
EXECUTIVE SUMMARY
The Town of Atherton aims to enhance safety and efficiency at the intersection of Alameda de las Pulgas and Atherton Avenue, as highlighted by the Alameda de las Pulgas Corridor Traffic Study. Currently, the Level of Service (LOS) at this intersection is poor with significant delays. Initial planning for installation of a traffic signal to improve traffic flow at this intersection is concurrently underway. This feasibility study explores the viability of a roundabout at this intersection as an alternative solution. The proposed roundabout would improve traffic flow, reduce collision conflict points, improve pedestrian safety, and efficiently accommodate all users.
The implementation of a roundabout is feasible if key obstacles can be effectively managed. The primary challenge is property acquisition, followed by utilities relocation. Additional considerations include cost, timeline of permitting and environmental clearance, and grant-related deadlines. Finally, public education on using the roundabout will be necessary, although it is the least critical factor. While the preferred design alternative remains open for consideration, addressing these issues will be crucial to the success of implementing a roundabout.
INTRODUCTION
The Town of Atherton, located within the County of San Mateo, is looking at improvements for all modes of travel at the intersection of Alameda de las Pulgas and Atherton Avenue after the release of the Alameda de las Pulgas Corridor Traffic Study. Refer to Figure 1 for an aerial image of the location. This intersection is currently an all-way stop controlled (AWSC) intersection, located within the Towns’s Residential District R1-A.
This roundabout feasibility report evaluates the potential challenges and benefits of implementing a roundabout at the intersection of Alameda de las Pulgas and Atherton Avenue, analyzing factors to determine its viability in enhancing overall efficiency and safety.
Figure 1: Intersection of Alameda de las Pulgas and Atherton Avenue.
Source: Google Earth Pro
EXISTING CONDITIONS
Alameda de las Pulgas (ADLP) is a north-south corridor classified as a minor arterial with a speed limit of 30 miles per hour (mph). It currently features an existing class II bikeway with a 6-feet (ft) bike lane without a buffer. ADLP also serves as a bus route for SamTrans, which is a bus service throughout San Mateo County.
There are two (2) bus stops at the north leg of the intersection at Atherton Avenue for northbound and southbound bus route 87.
Atherton Avenue serves as an east-west corridor, classified as a collector with a speed limit of 30 mph east of ADLP and 25 mph west of ADLP. Currently, Atherton Avenue is a class III bikeway with bike route sharrows.
Collision History Data
Collision history data of the Town was downloaded from the Transportation Injury Mapping System (TIMS) for the latest available five (5) years. From January 1, 2019, to December 31, 2023, only one (1) collision appeared on TIMS, which occurred 60 feet south of the intersection of ADLP and Atherton Avenue in May of 2022. The crash severity was level 3 for suspected minor injury or visible injury.
However, according to crash history data collected from the Atherton Police Department from 2019 to 2024, a total of two (2) collisions were reported at the intersection, including the same one shown from TIMS on May of 2022, which involved a bicycle and a vehicle. The other collision reported from the Atherton Police Department occurred in August of 2022, which only involved an object with a vehicle. Both collisions were determined to be the result of speeding.
Traffic Counts
Using the Streetlight InSight software provided by the Town, average weekday peak hour turning movement volumes are shown in the following figure below from the years 2018 to 2023.
Figure 2: Turning Movement Volumes.
XX(XX) = AM (PM) Peak Hour Turning Movement Volumes
Source: Streetlight InSight, 2018 to 2023
Level of Service
Based on the turning movement volumes, the following tables show existing and predicted level of service for the project intersection.
Table 1: Intersection of ADLP and Atherton Avenue Level of Service (LOS) – Existing Conditions.
Traffic Control AM Peak Hour PM Peak Hour
Delay (seconds/vehicle) LOS Delay (seconds/vehicle) LOS AWSC 87.2 F 91.9 F
Source: Alameda de las Pulgas Corridor Traffic Study by AMG, 2018 Table 2: Intersection of ADLP and Atherton Avenue Level of Service (LOS) – Design Alternatives.
Design Alternatives AM Peak Hour PM Peak Hour
Delay (seconds/vehicle) LOS Delay (seconds/vehicle) LOS AWSC (Existing) (No Build) 87.2 F 91.9 F
Traffic Signal Alternative 17.6 B 16.8 B
Roundabout Alternative 12.3 B 7.1 A
Source: Alameda de las Pulgas Corridor Traffic Study by AMG, 2018 With the information from Table 2, design alternatives for the improvements of the project intersection were developed and are discussed in the following section.
DESIGN ALTERNATIVES
Since the existing LOS of this report location is F, improvements to the intersection are necessary to bring it back to an acceptable LOS.
The following design alternatives for the intersection of ADLP and Atherton Avenue are proposed for the Town:
1. Traffic Signal Alternative
2. Neighborhood Traffic Circle Alternative
3. Roundabout Alternative
The following subsections will provide a general description and overview of each alternative considered for the project location.
1. Traffic Signal Alternative
The Town is considering the implementation of a new traffic signal for the intersection of ADLP and Atherton Avenue, but that alternative evaluation is currently being handled by an outside consultant.
2. Neighborhood Traffic Circle Alternative
Neighborhood traffic circles are typically built at local street intersections for traffic calming or aesthetics. The intersection approaches are either uncontrolled or stop-controlled. Since ADLP and Atherton Avenue are minor arterial and collector streets, respectively, a neighborhood traffic circle is not considered for this location at this time.
3. Roundabout Alternative
The California Manual of Uniform Traffic Control Devices (CA MUTCD) defines a roundabout as “a circular intersection with yield control at entry, which permits a vehicle on the circulatory roadway to proceed, and with deflection of the approaching vehicle counterclockwise around a central island.” Different types of roundabouts include mini-roundabout, compact roundabout, single-lane roundabout, and multilane roundabout. Each type of roundabout is defined by the features as shown in the Table 3 below.
Table 3: Comparison of Common Roundabout Features Across Types of Roundabouts.
Source: NCHRP Research Report 1043: Guide for Roundabouts ICD = inscribed circle diameter
The ICD values provided in the table are descriptive and not to be used as strict design constraints. It is a flexible dimension that can be adapted to meet the specific requirements of different locations, emphasizing the importance of not using ICD values as rigid design constraints but rather as guidelines for effective roundabout design. Roundabouts can be adapted to various site conditions, and configurations with an ICD of 90 feet or more often provide sufficient space for necessary design elements while meeting operational and safety performance targets.
For the roundabout alternative, an initial concept was developed to include accommodation of bicycle and pedestrian traffic based off the Town’s Bike Pedestrian Master Plan, see Figure 3 on the following page. The roundabout alternative concept will be described further in the following section, Roundabout Alternative Approach. Please note that the central island does not necessarily need to be circular in shape. While this concept iteration in Figure 3 is drawn to fit within the public right-of-way, it is important to recognize that other limitations may arise. Further refinement stages will be needed to fully develop the final design of the roundabout.
ROUNDABOUT ALTERNATIVE APPROACH
In developing the roundabout design concept for the intersection of ADLP and Atherton Avenue, we have thoroughly examined aspects such as design, coordination, property acquisitions, scheduling, cost, education, and safety.
Design Considerations
Designing a single-lane roundabout involves considering various elements to ensure safety, efficiency, and accessibility for all users, including pedestrians, bicyclists, commuter vehicles, heavy vehicles, emergency vehicles, and buses. Figure 3 can be referred to when going over the considerations of these users along with the conceptual layout of the roundabout features.
The Town proposed to enhance the existing bike lane along ADLP by adding a 2-ft buffer between the bike lane and vehicle travel lane per the Town’s Bike and Pedestrian Master Plan. Also, the Town proposes to convert Atherton Avenue, east of ADLP, to a class II bikeway with a dedicated 4-ft bike lane (no buffer) with 11 to 12-ft travel lanes and 3 to 4-ft shoulders according to the Town’s Bike and Pedestrian Master Plan. This will require widening the existing soft shoulders with drainage improvements.
Pedestrians use sidewalks, mixed-use paths, and crosswalks to navigate their journeys safely and efficiently.
Crosswalks are placed a short distance from the roundabout's entries and exits, ensuring they are highly visible and illuminated with streetlights. To enhance safety, concrete splitter islands are included in the concept, allowing pedestrians to cross one direction of traffic at a time, thus providing a secure and manageable crossing experience.
ADA compliance is crucial in the conceptual design of a roundabout. Key elements include providing welldesigned curb ramps at all pedestrian crossings, ensuring these crossings are clearly marked and equipped with raised truncated domes to aid visually impaired individuals. Sidewalks and mixed-use paths are to be wide enough to accommodate wheelchairs and other mobility devices. For the Town’s conceptual design, the sidewalks are proposed to be 5-feet wide, and the mixed-use path to be 10-feet wide.
Bicyclists have varying abilities and comfort levels. When approaching the roundabout, bicyclists have two options: they can merge from the bike lane into the vehicle traffic to navigate through the circulatory roadway, or they can use the bike on-ramp to access a 10-foot mixed-use path on the curb. On the mixed-use path, they can continue in their desired direction. When crossing the street, bicyclists use the crosswalk and then continue on the mixed-use path. To rejoin the bike lane, they can use the designated bike off-ramp and continue their journey. Bicyclists that choose to merge into the vehicle traffic to navigate through the circulatory roadway can then continue on the designated bike lane after exiting the roundabout.
Vehicles must adhere to specific guidelines to ensure smooth and safe traffic flow. As vehicles approach a roundabout, they are required to slow down and yield to traffic already circulating within the roundabout.
Drivers should only enter when there is sufficient space and, once inside, maintain a staggered spacing to allow for the entry of other vehicles. Upon reaching their desired exit, vehicles should signal and exit appropriately. Special accommodations are made for trucks and emergency vehicles. Traversable truck aprons, as shown in Figure 3, and mountable curbs on the central and splitter islands facilitate easier navigation for larger and emergency vehicles. In the event of an emergency vehicle entering the roundabout, other vehicles should not stop within the circulatory roadway but should instead exit the roundabout and move aside to allow the emergency vehicle to pass.
Bus stops are ideally positioned on the far-side of an intersection because positioning immediately beyond the pedestrian crossing improves visibility of pedestrians for exiting vehicles, thereby enhancing safety. This setup allows buses to depart while pedestrians are still crossing, reducing the risk of pedestrian-vehicle conflicts. As later mentioned in Table 4, there is one existing bus stop at the project intersection that needs coordination to be relocated from the near-side to the far-side of the intersection along Alameda de las Pulgas.
Features of the roundabout concept design include splitter islands and central island. Splitter islands serve to slow down traffic before entering the roundabout and provide safe refuge areas for pedestrians. The central island must be clearly visible to approaching drivers, which can be achieved through distinctive landscaping or markings. Additionally, clear, reflective signage and road markings are essential to guide all users, and lowmaintenance landscaping in both the central island and splitter islands can enhance visibility and aesthetics without obstructing sight lines. Single-lane roundabouts with a 90 feet inscribed circle diameter are suitable for daily service volumes of up to approximately 25,000 vehicles.
Impacts to the side streets along the Alameda de las Pulgas corridor will vary compared to a signalized intersection. The roundabout facilitates a staggered flow of vehicles, creating gaps in traffic that make it easier for side street vehicles to enter the ADPL corridor. Unlike signalized intersections, which create platoons of vehicles, the continuous movement in a roundabout ensures regular breaks, enhancing access from side streets.
Coordination and Relocation Items
The roundabout alternative concept faces some challenges requiring the relocation of utilities among other items. Table 4 lists the items, quantities, and action required to address these obstacles in order to implement a roundabout.
Table 4: Relocation Items.
Level of Challenge,
High (1) to Low (8)
Item Quantity Location Notes
1 Property R/W Acquisition 2.30 SQFT SE Corner;
SW Corner
Requires coordination; significant
cost and schedule impacts.
2 Overhead Utility Pole with
Luminaire
1 EA NW Corner Requires coordination; significant
cost and schedule impacts.
3 Drainage Inlet 2 EA SE Corner;
SW Corner
Requires coordination, design, and
additional cost.
4 Control Cabinet 2 EA SE Corner Requires coordination, design, and additional cost.
5 Pull Boxes Various Varies Requires coordination, design, and additional cost.
6 Bus Stop 1 EA NE Corner Requires coordination, design, and additional cost.
7 6” to 8” Diameter Trees 3 EA SE Corner Relocation to be determined if there is enough clearance on the mixeduse path to meet ADA requirements. 8 Automated License Plate
Reader (ALPR) Monitoring
Device Equipment & Pole
2 EA NW Corner;
NE Corner
Town-owned and can be easily
relocated.
Source: Interwest, 2024
The items in the above Table 4 are also called out in the Roundabout Alternative Concept, Figure 3.
Property Right-of-Way Acquisitions
The Town shared the San Mateo County GIS Property Maps Portal to provide approximate property right-ofway boundaries. A map was extracted from the GIS Property Maps Portal, see Appendix A, and overlayed on the concept (Figure 3) to demonstrate the approximate locations of the right-of-way property lines. As shown in the roundabout concept, Figure 3, there is minor encroachment to the adjacent properties in order to widen the roadway to include proper safe pedestrian and bicycle facilities. In total, approximately 2.3 square feet of private property overlaps with the concept roundabout. Despite that, approximate locations of property fences are outlined in the roundabout concept, which does not impact the conceptual design.
Schedule
A tentative timeline schedule to implement a roundabout is broken down in the following table. The table includes planning, design, rounds of reviews, coordination, utilities relocation, permitting and environmental clearance, project bidding, and construction. Grant-related deadlines should also be taken into consideration.
Table 5: Roundabout Schedule.
No. Milestone Description Assigned To Estimated Number of Days 1 Preliminary Concept/Design Consultant 36
2 Town Review Town 7
3 35% Design Consultant 21
4 Town Review Town 7
5 65% Design Consultant 21
6 Town Review Town 7
7 95% Design and Draft PS&E Consultant 7
8 Town Review Town 7
9 Final Design and PS&E, Bid Set Consultant 24
10 Town Review Town 12
11 Coordination Various Agencies **
12 Utilities Relocation PG&E and Others **
13 Permitting Various Agencies **
14 Environmental Clearance Various Agencies **
15 Bidding Town 60
16 Construction Contractor 365
Source: Interwest, 2024
** Estimated number of days is dependent on a number of factors.
The typical service life of a roundabout is approximately 25 years compared to 10 years for a traffic signal. This lifespan can be influenced by factors such as traffic volume, environmental conditions, and maintenance practices. Properly designed and maintained roundabouts can provide safe and efficient operation for decades, making them a long-term investment in traffic management and road safety.
Preliminary Cost Estimate
Based on the concept for the roundabout design alternative, a preliminary cost estimate was developed. Refer to the following table, and Appendix B, for a breakdown with the total cost of $1,506,742.60.
Table 6: Roundabout Alternative Preliminary Cost Estimate.
Item
No. Item Description Quantity Unit Unit Price Cost
General Items
1 Property Right of Way Acquisition 2.30 SF $ *** $ *** Removal Items
2 Excavation, Demolition, and Grading 1.63 ACRE $ 22,000.00 $ 35,860.00 3 Remove Concrete Curb and Gutter 2,720.00 LF $ 30.00 $ 81,600.00 4 Remove Thermoplastic Traffic Stripe 2,920.00 LF $ 1.50 $ 4,380.00 5 Remove Thermoplastic Pavement Marking 270.50 SF $ 3.00 $ 811.50 6 Remove Roadside Sign and Post 5.00 EA $ 100.00 $ 500.00 Relocation Items
7 Relocate Roadside Sign and Post 9.00 EA $ 250.00 $ 2,250.00 8 Relocate License Reader Pole and Equipment 2.00 EA $ 500.00 $ 1,000.00 9 Relocate Drainage Inlet 2.00 EA $ 3,500.00 $ 7,000.00 10 Relocate Utility Cabinet and Concrete Base 2.00 EA $ 1,000.00 $ 2,000.00 11 Adjust Utility Box / Cover to Grade 5.00 EA $ 800.00 $ 4,000.00 12 Transplant Tree 3.00 EA $ 1,250.00 $ 3,750.00
13 Relocate Overhead Utility Pole with Luminaire 1.00 EA $ 100,000.00 $ 100,000.00 Installation Items
14 Signing and Striping 1.00 LS $ 31,109.50 $ 31,109.50 15 Roadway Pavement 33,665.00 SF $ 5.00 $ 168,325.00
16 Concrete Curb and Gutter 2,635.00 LF $ 25.00 $ 65,875.00 17 Concrete Sidewalk 17,285.00 SF $ 30.00 $ 518,550.00
18 Concrete Splitter Islands and Central Island 4,075.00 SF $ 25.00 $ 101,875.00 19 Traversable Truck Apron 2,310.00 SF $ 30.00 $ 69,300.00 20 Pedestrian Curb Ramp 8.00 EA $ 5,000.00 $ 40,000.00
21 Bicycle Curb Ramp 8.00 EA $ 5,000.00 $ 40,000.00
22 Truncated Domes 252.00 SF $ 60.00 $ 15,120.00
23 Vegetation 3,823.00 SF $ 20.00 $ 76,460.00
Subtotal $ 1,369,766.00
10% Contingency $ 136,976.60
Total Cost $ 1,506,742.60
Source: Interwest, 2024
*** Cost is dependent on a number of factors.
While the upfront costs for constructing a roundabout are higher than those for installing a traffic signal, the ongoing operating and replacement costs are significantly lower. The return on investment for constructing a roundabout becomes evident through energy savings and reduced maintenance expenses. Roundabouts
require less ongoing maintenance, which mainly includes signage and striping, compared to traffic signals that incur ongoing costs for power and energy.
Education
Educating the community about roundabouts is crucial for their successful implementation and effective use.
Public awareness campaigns should inform residents about the benefits of roundabouts, such as improved safety and traffic flow. Instructional materials, including brochures, videos, and online resources, should be developed to explain how to navigate roundabouts safely. When the new roundabout is installed, advanced warning signs for all approaches to the improved intersection will be posted for 6-12 months to inform travelers of a new roadway condition ahead.
Safety
Roundabouts are designed to enhance safety significantly by reducing vehicle speeds, with entry and exit speeds typically ranging from 15 to 25 mph. These lower speeds decrease the severity of collisions, often resulting in minor sideswipe or rear-end accidents instead of high-severity right-angle or head-on collisions.
As previously mentioned, only two (2) collisions have occurred, and both were due to speeding. The implementation of a roundabout will help to limit speed related collisions in the future, as roundabouts inherently reduce vehicle speeds and have fewer conflict points compared to regular intersections, as shown in Figure 4. Additionally, roundabouts promote a continuous flow of traffic, reducing the risk of rear-end collisions common at intersections with traffic signals or stop signs. Pedestrian safety is also improved through slower vehicle speeds and crosswalks positioned slightly away from entries and exits of the roundabout, enhancing visibility and reaction time with pedestrians only having to check oncoming traffic in one direction at a time. Refuge islands also provide a safe crossing point for pedestrians. This steady movement leads to a smoother and safer driving experience, significantly reducing collision rates and injuries, making roundabouts a safer alternative to traditional intersections for drivers and pedestrians alike.
Figure 4: Intersection Conflict Points.
ENVIRONMENTAL REVIEW
The California Environmental Quality Act (CEQA) and the National Environmental Policy Act (NEPA) require local or state, and federal agencies, respectively, to assess the environmental impacts of their proposed actions prior to making decisions. These Acts establish a policy of sustainability to “create and maintain
conditions under which [human] and nature can exist in productive harmony to fulfill the social and economic requirements of present and future generations” (2024 CEQA Statutes and Guidelines).
The implementation of roundabouts aligns seamlessly with the Town's commitment to addressing climate change, as outlined in its Climate Action Plan. By reducing gas consumption and minimizing car idling, roundabouts contribute to cleaner air and support the Town's goal of reducing its carbon footprint. This initiative is further reinforced by the Town's General Plan, which emphasizes the preservation of scenic routes and environmental quality, aligning with the CEQA guidelines.
Environmental impact assessment is still pending and may be handled for the next phase. The environmental consultation with Caltrans raised a concern about cultural resources. Thus, the Town is going to seek additional information about Caltrans concerns.
CONCLUSION
Roundabouts serve as a sustainable alternative that promotes both safety and traffic calming. Unlike traditional traffic signals, which primarily function as traffic control devices, roundabouts are a proven safety countermeasure that enhances road safety while also providing aesthetic improvements through the incorporation of green spaces and vegetation. This approach not only enhances the visual appeal of the Town but also fosters a safer and more sustainable transportation infrastructure for residents and visitors alike.
Based on the findings of this feasibility study, implementing a roundabout at the intersection of Alameda de las Pulgas and Atherton Avenue presents a viable option that could significantly improve traffic flow, enhance safety for all users, and provide a long-term solution for the Town of Atherton. While the project faces challenges, such as property acquisition and utilities relocation, the long-term benefits outweigh the initial investment and complexities. Strategic planning and effective management of these challenges are essential to realizing the full potential of the roundabout, making it a highly effective and sustainable improvement for the Town of Atherton.
REFERENCES
2024 CEQA Statutes and Guidelines:
https://www.califaep.org/docs/2024_CEQA_Statute_and_Guidelines_Handbook.pdf California Manual of Uniform Traffic Control Devices (CA MUTCD) 2014 Revision 8 https://dot.ca.gov/-/media/dot-media/programs/safety-programs/documents/ca-mutcd/rev8/camutcd2014- rev8-all.pdf
Climate Action Plan
https://www.ci.atherton.ca.us/DocumentCenter/View/3535/CAP-Admin-Draft-ATT-2-10-19-16-FINAL-ADMINDRAFT-002?bidId= Climate Change in Atherton
https://climateaction.ci.atherton.ca.us/category/transportation NCHRP Research Report 1043: Guide for Roundabouts
https://nap.nationalacademies.org/catalog/27069/guide-for-roundabouts SamTrans
https://www.samtrans.com/
San Mateo County GIS Property Maps Portal
https://gis.smcgov.org/Html5Viewer/?viewer=raster
Streetlight InSight
https://insight.streetlightdata.com
Transportation Injury Mapping System (TIMS)
https://tims.berkeley.edu/
Town of Atherton Bike Pedestrian Master Plan
https://www.ci.atherton.ca.us/298/Bike-Pedestrian-Master-Plan Town of Atherton General Plan 2019
https://www.ci.atherton.ca.us/DocumentCenter/View/7325/General-Plan-2019_FINAL-DRAFT
APPENDIX
Agency: Town of Atherton
Project: Roundabout Feasability
Location: Alameda de las Pulgas and Atherton Avenue
Date: 8/13/2024
Item No. Item Description Quantity Unit Unit Price Cost General Items
1 Property Right of Way Acquisition 2 .30 SF $ - - $
Removal Items
2 Excavation, Demolition, and Grading 1 .63 ACRE $ 35,860.00 22,000.00 $ 3 Remove Concrete Curb and Gutter 2,720.00 LF $ 81,600.00 30.00 $ 4 Remove Thermoplastic Traffic Stripe 2,920.00 LF $ 4,380.00 1.50 $ 5 Remove Thermoplastic Pavement Marking 270.50 SF $ 811.50 3.00 $ 6 Remove Roadside Sign and Post 5 .00 EA $ 500.00 100.00 $ Relocation Items
7 Relocate Roadside Sign and Post 9 .00 EA $ 2,250.00 250.00 $ 8 Relocate License Reader Pole and Equipment 2.00 EA $ 1,000.00 500.00 $ 9 Relocate Drainage Inlet 2 .00 EA $ 7,000.00 3,500.00 $ 10 Relocate Utility Cabinet and Concrete Base 2.00 EA $ 2,000.00 1,000.00 $ 11 Adjust Utility Box / Cover to Grade 5 .00 EA $ 4,000.00 800.00 $ 12 Transplant Tree 3 .00 EA $ 3,750.00 1,250.00 $
13 Relocate Overhead Utility Pole with Luminaire 1.00 EA $ 100,000.00 100,000.00 $ Installation Items
14 Roadside Sign 8 .00 EA $ 2,400.00 300.00 $
15 Roadside Sign and Post 28.00 EA $ 9,800.00 350.00 $
16 6" White Thermoplastic Traffic Stripe - Detail 27B 9 0.00 LF $ 180.00 2.00 $ 17 6" White Thermoplastic Traffic Stripe - Detail 39 1, 760.00 LF $ 3,520.00 2.00 $ 18 6" White Thermoplastic Traffic Stripe - Detail 39A 4 00.00 LF $ 800.00 2.00 $ 19 12" White Thermoplastic Traffic Stripe - Wide Dotted Circulatory Roadway Edgeline 92.00 LF $ 276.00 3.00 $ 20 6" Yellow Thermoplastic Traffic Stripe - Detail 22 2 05.00 LF $ 512.50 2.50 $ 21 6" Yellow Thermoplastic Traffic Stripe - Detail 25A 1,140.00 LF $ 2,850.00 2.50 $ 22 6" Yellow Thermoplastic Traffic Stripe - Detail 29 1 ,870.00 LF $ 4,675.00 2.50 $ 23 White Thermoplastic Crosswalk Line 440.00 SF $ 3,520.00 8.00 $ 24 White Thermoplastic Yield Line 36.00 SF $ 288.00 8.00 $ 25 White Thermoplastic Sharrow Pavement Marking 115.00 SF $ 920.00 8.00 $ 26 White Thermoplastic Bike Lane Pavement Marking 63.00 SF $ 504.00 8.00 $ 27 White Thermoplastic Type VII (L) Arrow Pavement Marking 108.00 SF $ 864.00 8.00 $ 28 Roadway Pavement 3 3,665.00 SF $ 168,325.00 5.00 $
29 Concrete Curb and Gutter 2,635.00 LF $ 65,875.00 25.00 $ 30 Concrete Sidewalk 1 7,285.00 SF $ 518,550.00 30.00 $ 31 Concrete Splitter Islands and Central Island 4,075.0 0 SF $ 101,875.00 25.00 $ 32 Traversable Truck Apron 2,310.00 SF $ 69,300.00 30.00 $ 33 Pedestrian Curb Ramp 8 .00 EA $ 40,000.00 5,000.00 $ 34 Bicycle Curb Ramp 8 .00 EA $ 40,000.00 5,000.00 $
35 Truncated Domes 252.00 SF $ 15,120.00 60.00 $
36 Vegetation 3,823.00 SF $ 76,460.00 20.00 $
Subtotal 1,369,766.00 $
10% Contingency 136,976.60 $
Total Cost 1,506,742.60 $
Preliminary Cost Estimate
California MUTCD 2014 Edition Page 1433
(FHWA’s MUTCD 2009 Edition, including Revisions 1,2, &3, as amended for use in California) Chapter 9C – Markings
Part 9 – Traffic Control for Bicycle Facilities
November 7, 2014
Revised March 9, 2018 Revised December 7, 2023 Page 29 of 43 ADLP/Atherton Avenue
Utility and Right-of-Way Pictures
PG&E Transmission Pole
AT&T Communications Cabinets
Frontage of 303 Atherton Avenue
At corner
302 Atherton
297 Atherton Avenue
296 Atherton Avenue
ADLP/Atherton Avenue
Traffic Signal Conceptual Intersection Layout
Item No. 2
Town of Atherton
CITY COUNCIL STAFF REPORT – STUDY SESSION
TO: HONORABLE MAYOR AND CITY COUNCIL
GEORGE RODERICKS, CITY MANAGER
FROM: ROBERT OVADIA, PUBLIC WORKS DIRECTOR
DATE: SEPTEMBER 4, 2024
SUBJECT: DIRECTION AND FEEDBACK REGARDING TRAFFIC STUDIES
AND RECOMMENDATIONS
RECOMMENDATION
It is recommended that the Council review and provide feedback and direction to staff regarding prioritization of traffic improvements.
BACKGROUND
Over the last several years, a variety of traffic studies have been completed to assist the Town in outlining areas where traffic flows can be improved and cut-through traffic reduced in various locations. These studies include:
Alameda de las Pulgas Corridor Traffic Study – AMG 2019 Local Traffic Flow – Long Range Planning Solutions Study – TJKM 2019 El Camino Real/Selby Lane Traffic Analysis – Mark Thomas 2017 Neighborhood Traffic Management Action Plan
Local Roadway Safety Plan (draft 2024)
As background for discussion of this item, the Council was provided with copies of the above reports for early review.
Each of the studies included recommendations for improvements and the Town, with the approval of the City Council, has initiated various Capital Improvement Projects using the priorities and direction provided by these studies. However, a refresh of Council consideration and confirmation of priorities would be helpful as staff moves forward with projects that improve mobility and safety along Town roadways.
In addition to the above studies, the Town is working with the San Mateo County Transportation Authority in evaluating complete streets options for El Camino Real to accommodate pedestrian
Traffic Studies Feedback and Direction
SEPTEMBER 4, 2024
and bicycle facilities on this important route, and has released a request for proposals to update the Town’s Bicycle and Pedestrian Master Plan. These efforts will also be used in outlining priorities for improvements to our roadway network. The Town also completed a traffic impact study associated with its proposed Housing Element which identified impacts and potential improvements.
ANALYSIS
Major findings and recommendations of the above reports include the following:
Alameda de las Pulgas Corridor Traffic Study – AMG 2019 • Intersection of ADLP and Woodside Road – Update signal timing and provide traffic signal coordination between Woodside Road and Hull Avenue. (Outside of Town Limits – Caltrans signal)
• Intersection of ADLP and Hull Avenue – Provide traffic signal coordination between Woodside Road and Hull Avenue and reconstruct all the corner ramps to meet current ADA standards. (Outside of Town Limits – SM County signal) o San Mateo County upgraded ramps in association with their street slurry seal project
o The Town can request San Mateo County evaluate and adjust signal timing in a coordinated manner with the completion of the Alameda de las Pulgas Traffic and Safety Improvements project
• Intersection of ADLP and Stockbridge Avenue – Installation of a roundabout or a traffic signal is expected to reduce traffic delay at the intersection. However, due to restricted right of way, it was recommended to install a traffic signal. (Shared intersection between Town and SM County)
o Town has included installation of a pedestrian activated rectangular rapid flashing beacon to improve pedestrian visibility and mobility in the FY 23-24 Capital Improvement Program. The project design is approximately 90% complete and was be submitted to San Mateo County for review. The Town will be working with San Mateo County to secure a contractor once the design has been approved. • Intersection of ADLP and Atherton Avenue – Installation a roundabout or a traffic signal at this intersection is expected to improve traffic operations and intersection LOS from existing conditions. However, due to restricted right of way and the potential need for property acquisition to install a roundabout, installation of a signal was deemed more feasible.
o The reconfiguration and signalization of this intersection is included in the scope of the Alameda de Las Pulgas Traffic and Safety Improvements Project, which is currently in design. The City Council has also approved an additional analysis to better determine feasibility of a roundabout at this location. The roundabout analysis is the subject of a separate staff report.
• Intersection of ADLP and Camino Al Lago – Installation of a traffic signal at this intersection and remove the existing mid-block crosswalk and signal on ADLP approximately 150 feet south of this intersection; and, reconfigure the intersection to
Traffic Studies Feedback and Direction
SEPTEMBER 4, 2024
shorten the crossing distances. (Shared intersection between Town and SM County; midblock crossing SM County) – o The signalization of this intersection, along with the removal of the mid-block pedestrian activated signal, is included in the scope of the Alameda de Las Pulgas Traffic and Safety Improvements Project, which is currently in design. • Intersection of ADLP and Valparaiso Avenue – Installation of protected left-turn phases for the ADLP approaches at this intersection (Outside of Town Limits – SM County signal)
• [GR1]Include a summary of next steps - which ones are in 2024/25 CIP, which ones are programmed in out years.
Local Traffic Flow/ Long Range Planning Solutions Study – TJKM 2019 Alameda de Las Pulgas:
• Left-turn restrictions from ADPL to Stockbridge Avenue and to Polhemus Avenue – restrict during the am peak (Stockbridge Avenue intersection is shared with SM County). o Review of the potential restriction of turning movements has been deferred pending completion of eth Alameda delas Pulgas Traffic and Safety Improvements project.
• Signalization of the ADPL/Atherton Avenue intersection; Square-out the intersection by removing existing pork-chop and adding an exclusive right-turn lane making it safer for all modes of transportation; Provide protected left-turn phasing along Alameda De Las Pulgas with westbound right-turn overlap for Atherton Avenue. o As noted above, the reconfiguration and signalization of this intersection is included in the scope of the Alameda de Las Pulgas Traffic and Safety Improvements Project, which is currently in design.
• Meter traffic along the corridor upon signalization
o This option would be considered in the implementation of the Alameda de las Pulgas Traffic and Safety Improvements project and coordinated with San Mateo County
Valparaiso Avenue:
• The intersections of Valparaiso Avenue/Emilie Avenue and Valparaiso Avenue/Elena Avenue operate at LOS F during all study peak periods. Though these intersections meet peak hour signal warrants, to operate at acceptable level of service, exclusive left-turn lanes have to be provided along with the signalization at the intersections which would require ROW take. Due to ROW constraints this would not be a viable option at this time.
TJKM also indicated that a one-way circulation loop between Elena Avenue and Emilie Avenue may improve operations. As Valparaiso is shared jurisdictionally with Menlo Park, coordination with Menlo Park would be needed.
o The Town is currently working with the City of Menlo Park on the slurry seal and restriping of Valparaiso Avenue to include buffering of the bike lanes. No action has been taken regarding evaluation of roadway widening, signalization or implementation of a one-way traffic loop.
Middlefield Road:
Traffic Studies Feedback and Direction
SEPTEMBER 4, 2024
• Signalization of Middlefield Road/Fair Oaks Lane and Middlefield Road/Watkins Avenue intersections
o This item has not yet been programmed.
• Improve signal timings along Middlefield Road by updating the coordination plans through the corridor.
o Retiming and coordination of the signals along Middlefield Road from Marsh Road to Ringwood Avenue was completed through the Metropolitan Transportation Commission (MTC) Program for Arterial System Synchronization (PASS).
• Provide Northbound Left-Turn restrictions from Middlefield Road onto Glenwood Avenue during the a.m. peak period.
o This item has not been implemented.
• Meter the traffic along the corridor at controlling intersections like Middlefield Road/Fair Oaks Lane, Middlefield Road/Marsh Road and Middlefield Road/Oak Grove Avenue. o Signal timing along the corridor has been updated. Metering traffic north of Marsh Road would require upstream signalization, which has not been programmed.
• The study also made recommendations on street classification with proposed guidelines to support walking, biking, and transit usage along various streets o Certain street classifications were included in the adoption of the Circulation Element of the General Plan.
El Camino Real/Selby Lane Traffic Analysis – Mark Thomas 2017 • The study determined that most accidents, during the study period, could be attributed to vehicular turning movements. Based upon the review of the accident history, it was advised that controlling and regulating the movement of vehicles by installation of a traffic signal or physically limiting the number of movements by utilizing raised medians would improve the safety and operations of the Selby Lane/ECR intersection. Although, at the time, Caltrans preferred the traffic signal alternative since they believe it’s a better solution for reducing vehicular collisions and provide a safer crossing for pedestrians and bicycles, based on outreach at the time, the non-signalized alternative was considered less controversial for the Selby Lane neighborhood.
o Funding for improvements to this intersection was included in the Town‘s One Bay Area Grant (OBAG) application for the Selby Lane Bike Lanes Project.
Grant funding for the project was not approved. The current El Camino Real Complete Streets Gap Closure Study is evaluation the El Camino Real from north of Selby Lane to Valparaiso Avenue and will include recommendations on how to improve safety of all roadway users along the corridor.
Neighborhood Traffic Management Action Plan
• Recommended replacement of various signs to increase visibility – Completed • Restriping school crossings and installation of advance (shark tooth) yield lines – Completed
• Recommended changes to centerline striping on Atherton Avenue and Stockbridge Avenue – Completed
Traffic Studies Feedback and Direction
SEPTEMBER 4, 2024
• Recommended installation of speed humps in various locations to reduce speeding and cut-through traffic
o Partially completed – Staff has initiated outreach for the remaining speed humps identified: Selby Lane (east-west), Selby Lane (north-south), Stockbridge Avenue and Encinal Avenue. Staff has received a petition for the installation of speed humps from residents of Maple Avenue, which is currently being reviewed. • Recommended installation of turn restrictions in various locations o These have not yet been implemented.
• Improvement of the Fair Oaks Lane/Station Lane/LLoyden Drive intersection – Under construction
• Traffic and safety improvements along the Alameda de las Pulgas corridor – Included in the Alameda de Las Pulgas Traffic and Safety Improvements Project. • Bike lane improvements on Selby Lane, Atherton Avenue, Valparaiso Avenue (enhancement), Stockbridge Avenue, and Marsh Road
o Selby Lane Bicycle Lane Improvements are currently under design and enhancements to the bike lanes on Valparaiso Avenue are pending construction.
Evaluation of options of other bikeways will be included in the refresh of the Bicycle and Pedestrian Master Plan.
• Installation of a traffic signal at the Middlefield Road/Fair Oaks Lane intersection o This item has not yet been programmed
• Working with schools and school districts to implement rectangular rapid flashing beacons (RRFBs) at mid-block crossings via safe routes to schools or other funding programs
o Pending coordination and funding.
Local Roadway Safety Plan
The Local Roadway Safety Plane is intended to assist the Town in promoting a culture of roadway safety in Atherton’s departments, educational institutions, and residents, with a goal of reducing fatal and severe injury crashes to zero by 2050.
The Plan identified a High Injury Network (HIN) for the Town, including Motor Vehicle, Pedestrian and Bicyclist, including the following streets:
• El Camino Real (State Highway)
• Alameda de las Pulgas (bicycle)
• Middlefield Road (vehicle)
• Marsh Road (vehicle)
• Oak Grove Road (bicycle and pedestrian)
The Plane identified intersections for priority consideration, including the following streets:
• El Camino Real (State Highway)
• Valparaiso Avenue (shared with Menlo Park)
• Middlefield Road
• Alameda de las Pulgas
• Oak Grove Avenue
Traffic Studies Feedback and Direction
SEPTEMBER 4, 2024
Staff is planning on presenting the draft Local Roadway Safety Plan to the Transportation, Bicycle and Pedestrian Safety Committee for review and consideration at their upcoming meeting and would then bring the plan for review by the Council. Concurrent with the adoption of the plan would be consideration of designating “safety corridor” streets that would allow for speed limit reductions along those corridors per CVC 22358.7.
El Camino Real
The Town recently completed it’s California Environmental Quality Act (CEQA) review of it’s proposed Housing Element update. As part of the CEQA evaluation, the Town conducted a traffic analysis associated with the proposed changes. The study indicated that the added trips would not cause an adverse impact, as defined by the Town, at any of the signalized study intersections. The study did however identify issues at four unsignalized study intersections, including two on El Camino Real.
• Selby Lane - Selby Lane was estimated to experience long delays equivalent to LOS F under the study scenarios. The peak-hour volume signal warrant analysis indicated that peak-hour volumes at the intersection would meet the peak-hour volume warrant under all scenarios, both with and without the project traffic.
• Alejandra Avenue - During the AM peak hour, Alejandra Avenue at El Camino Real was estimated to experience long delays equivalent to LOS E under the study scenarios. The added project trips would increase the delay for this approach. The peak-hour volume signal warrant analysis indicates that peak-hour volumes at the intersection would not meet the peak-hour volume warrant under any scenario, with or without the project traffic, therefore signalization was not recommended.
As noted above, the Town is conducting a Complete Streets Gap Closure study for the El Camino Real corridor from north of Selby Lane to Valparaiso Avenue, in coordination with the San Mateo County Transportation Authority, the County of San Mateo, the City of Meno Park, Redwood City and Caltrans. This study will identity alternatives to improve safety and mobility of all users of the roadway. The evaluation will include key intersections and potential crossing improvements and/or signalization needs. It is important to note that the corridor is a State highway, under the jurisdiction of Caltrans and any improvements to El Camino Real must be coordinated and approved by Caltrans.
Funding for required design, environmental reviews and implementation would be sought after plan development and selection of a preferred alternative. Due to costs and complexities, it is anticipated that the Town would seek outside funds for the project as grant opportunities arise.
The City Council, through the Capital Improvement Program has prioritized and approved various traffic and safety improvements throughout the Town. As noted above, a number of the recommendations have been implemented or are in various stages of implementation.
The following recommendations are made to assist in prioritization of future projects:
• Complete ongoing projects such as the ADPL Corridor Traffic and Safety Improvements, Selby Bicycle Lanes and the El Camino Real Complete Streets Gap Closure Study
Traffic Studies Feedback and Direction
SEPTEMBER 4, 2024
• Continue implementation of the recommendations outlined in the Neighborhood Traffic Management Action Plan
• Complete improvements along Valparaiso Avenue, coordinated with Menlo Park • Update of the Town’s Bicycle and Pedestrian Master Plan, developed in 2014. The update of the master plan will assist in guiding and prioritizing bicycle and pedestrian projects desired by the Town and its residents
• Consider designating “safety corridor” streets that would allow for speed limit reductions along those corridors per CVC 22358.7
• Fund the next phase (design and environmental review) of the El Camino Real Complete Streets Gap Closure project following completion of the planning study • Evaluation of traffic signals on Middlefield Road at Watkins Avenue and at Fair Oaks Lane, concurrently review other potential traffic safety improvements along the Middlefield Road corridor
• Work with Caltrain on the required mitigation measures associated with the Peninsula Corridor Electrification Project including signalization of the El Camino Real / Watkins Avenue intersection and the Middlefield Road / Glenwood Avenue Intersection Additionally, as the Local Roadway comes for consideration by the Council, feedback on potential speed limit speed limit reductions along safety corridors and in school zones is being requested.
The City of Menlo Park is requesting consideration of a speed limit reduction on Valparaiso Avenue from the current 30 miles per hour to 25 miles per hour. Menlo Park, through their Vision Zero Action Plan, established Valparaiso Avenue as a safety corridor / high collision corridor, which allows for the additional 5 mile per hour speed limit reduction. To enact a concurrent reduction in the speed limit, the Town would also need to designate Valparaiso Avenue as a safety corridor. Staff is planning on presenting the draft Local Roadway Safety Plan to the Transportation, Bicycle and Pedestrian Safety Committee for review and consideration at their upcoming meeting and would then bring the plan for review by the Council.
Council feedback and direction regarding traffic and safety improvement priorities will assist staff as it develops programmatic funding outlooks and budgets, evaluates grant funding opportunities for project implementation, and responds to residents regarding traffic and safety concerns.
FISCAL IMPACT
None at this time.
GOAL ALIGNMENT
This Report and its contents are in alignment with the following Council Policy Goals:
• Goal Area B – Preserve Small Town Character and Quality of Life • Goal Area D – Manage Circulation and Improve Safety
• Goal Area F – Be Forward-Thinking, Well-Managed, and Well-Planned
POLICY FOCUS
Traffic Studies Feedback and Direction
SEPTEMBER 4, 2024
The Council’s policy focus should be on input and prioritization of traffic and safety improvements.
PUBLIC NOTICE
Public notification was achieved by posting the agenda, with this agenda item being listed, at least 72 hours prior to the meeting in print and electronically. Information about the project is also disseminated via the Town’s electronic News Flash and Atherton Online. There are approximately 1,200 subscribers to the Town’s electronic News Flash publications. Subscribers include residents as well as stakeholders –to include, but be not limited to, media outlets, school districts, Menlo Park Fire Protection District, service provides (water, power, and sewer), and regional elected officials.
COMMISSION/COMMITTEE FEEDBACK/REFERRAL
This item has not been before a Town Committee or Commission
ATTACHMENTS
None