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