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Appendix TRA
Access and Circulation Memo
332 Pine Street | 4th Floor | San Francisco, CA 94104 | (415) 348-0300 | Fax (415) 773-1790 www.fehrandpeers.com
MEMORANDUM
Date: June 26, 2019
To: Colum Regan, Aralon Properties
From: Jarrett Mullen and Daniel Jacobson, Fehr & Peers
Subject: 499 Forbes Boulevard Access & Circulation Assessment
SF19-1041
This memorandum presents an access and circulation assessment for a proposed life science office
building at 499 Forbes Boulevard in the City of South San Francisco (herein referred to as “Project”).
This assessment includes trip generation and distribution estimates and an evaluation of
multimodal site access and circulation. The findings of this assessment may help inform the Project
team’s site planning efforts and potential future analyses related to the environmental review
process.
Our key findings include the following:
• Trip Generation and Distribution: The project would generate approximately 881 daily,
96 AM peak hour, and 94 PM peak hour new motor vehicle trips. These volumes include a
35% trip reduction from the baseline trip generation forecast for consistency with City of
South San Francisco’s transportation demand management (TDM) ordinance. Outputs from
the City of South San Francisco travel demand model indicate approximately three quarters
of vehicle trips are anticipated to approach and depart the Project site from the west, via
Forbes Boulevard. The remainder would approach from the south and east.
• Peak Hour Traffic Signal Warrant Not Met Based on the trip generation and distribution
estimates, project trips were assigned to the Forbes Boulevard / Allerton Avenue
intersection approaches to determine if a traffic signal was warranted with the addition of
project trips. The traffic signal warrant was not met under project conditions in the AM or
PM peak hour.
• Off-Site Improvements The existing center landscape median on Forbes Boulevard should
be modified to permit direct left turns into the Project driveway from westbound Forbes
Mr. Colum Regan June 26, 2019 Page 2 of 8
Boulevard. Pedestrian facilities along the Project frontage should be enhanced to support
the Project TDM plan, including a landscaped buffer along the sidewalk and a new marked
crosswalk on the western approach of the Forbes Boulevard / Allerton Avenue intersection.
• Off-Street Auto Parking Supply The Project is required to provide2.83 parking spaces per
1,000 square feet of office space. The City may consider reducing off-street parking
requirements to support the Project’s trip reduction goals
Please contact Jarrett Mullen at (415) 426-2517 with questions.
Project Understanding & Setting
The Project site is located near the intersection of Forbes Boulevard and Allerton Avenue in the City
of South San Francisco’s East of 101 Area. Previously, the site was home to the Columbus Salame
factory, but it is currently vacant. It is our understanding the Project encompasses demolition of the
existing, approximately 54,000 square foot vacant salame factory and construction of a new 128,799
square foot life science office building. Motor vehicle and bicycle access is provided via a two-way
two-lane driveway that connects to Forbes Boulevard. Pedestrian access is provided via a walkway
that parallels the driveway.
Forbes Boulevard is a designated major arterial in The City of South San Francisco General Plan.
Along the Project frontage and south of The Allerton Avenue intersection, the roadway has two
vehicle lanes in each direction and a center median that alternates between a raised landscaped
median and a two-way left turn lane. The vehicular travelway, inclusive of the center median area,
is approximately 60-feet wide.
Continuous sidewalks are present along the north side of the roadway only and no dedicated
bicycle facilities are provided. East of the Allerton Avenue intersection, Forbes Boulevard includes a
wider landscaped center median, continuous sidewalks on both sides of the roadway, Class II
buffered bicycle lanes, and one travel lane in each direction. The City’s 2011 Bicycle Master Plan
and recent planning efforts considers reducing the number of travel lanes west of Allerton from
four to two lanes and extending bike lanes. The roadway connects to East Grand Avenue which
provides motor vehicle access to northbound U.S. Highway 101 and destinations to the west via
the local street network. Southbound access to U.S. Highway 101 is provided from Oyster Point
Boulevard via Gull Drive.
Mr. Colum Regan June 26, 2019 Page 3 of 8
Figure 1 – Site Plan
Commute.org provides three weekday peak-period public shuttle lines that travel along Forbes
Boulevard and connect to regional transit stations, including: the South San Francisco BART station
(10 daily roundtrips); the South San Francisco Caltrain station (seven daily roundtrips); and, the
South San Francisco Ferry Terminal (three daily round trips). The shuttle stop closest to the Project
site is at the intersection of Forbes Boulevard and Carlton Court, which is approximately 1,200 feet
west of the Project site.
Three of Genentech’s DNA Shuttle routes provide stops within 300 feet of the Project site (Blue,
Green, and Orange Lines). The DNA Shuttle connects to the Genentech campus as well as express
buses connecting to the greater Bay Area. While express bus services are intended for Genentech
employees only, the DNA Shuttle and buses to the Millbrae BART/Caltrain Station and Glen Park
BART Station are open to the public.
Mr. Colum Regan June 26, 2019 Page 4 of 8
Project Trip Generation & Distribution
Trip generation estimates were prepared for weekday daily, AM and PM peak hours using the
Institute of Transportation Engineers’ (ITE) Trip Generation Manual 10th Edition., which contain
motor vehicle trip generation data for a variety of land uses in North America. Trip Generation does
not contain specific data on life sciences and biotechnology uses, which can vary widely in their
employee densities and tend to be lower trip generators than typical office uses. Consequently,
estimating Project trip generation as an office may slightly overestimate its actual trip generation.
Project Trip Generation estimates are presented in Table 1. ITE estimates the Project would
generate 148 trips during the AM peak hour and 145 trips during the PM peak hour. However, in
accordance with the City of South San Francisco’s transportation demand management (TDM)
ordinance and C/CAG’s Congestion Management program, the Project would be required to
implement a TDM program. The City’s ordinance requires a 35 percent trip reduction for an FAR of
1.0. With this trip reduction, Project is estimated to generate 96 trips during the AM peak hour and
94 trips during the PM peak hour.
Although the site is not presently active, if an industrial tenant were to instead move into the site
similar to Columbus Salame, the site would generate approximately 28 AM peak hour trips and 24
PM peak hour trips.
Table 1: Weekday Project Trip Generation
Land Use Size Daily AM Peak Hour PM Peak Hour
In Out Total In Out Total
Office1 128.8 KSF 1356 127 21 148 23 122 145
35% TDM Trip Reduction (475) (44) (7) (52) (8) (43) (51)
Total 881 83 14 96 15 79 94
Previous Light Industrial2 54 KSF 263 25 3 28 3 21 24
Notes: 1. Rates based on ITE Trip Generation 10th Ed., 2017 fitted curve equation for Office (ITE 710)
2. Rates based on ITE Trip Generation 10th Ed., 2017 fitted curve equation for General Light Industrial (110). These volumes are shown to compare Project trip generation characteristics with a scenario where the existing building was reoccupied with a similar industrial use.
The distribution of Project trips along the roadway network is based on a review of outputs from
the City of South San Francisco Model TAZ 40023. The results are shown in Table 2 and Figure 2
Mr. Colum Regan June 26, 2019 Page 5 of 8
Table 2: Project Trip Distribution – City of South San Francisco Model
Street Percent of Project Trips
Forbes Boulevard – West of Project Site 76%
Forbes Boulevard – East of Allerton Avenue 18%
Allerton Avenue 6%
Figure 2 – Output from City of South San Francisco Traffic Model depicting most trips from TAZ 40023
occurring via Forbes Boulevard and East Grand Avenue
A traffic operations analysis was not performed at this time, although additional analysis may be
requested at the City’s discretion during the environmental review process. . A peak hour traffic
signal warrant analysis was performed at the Forbes Boulevard / Allerton Avenue intersection to
understand if the Project would require off-site traffic control improvements beyond what is
covered in the East of 101 Traffic Impact Fee program. The intersection currently operates with all-
way stop control. Using the 2014 California Manual on Uniform Traffic Control Devices (CAMUTCD)
methodology, existing weekday AM and PM peak hour turning movement counts collected in 2016,
and the trip generation and distribution estimates shown above, the signal warrant thresholds were
Mr. Colum Regan June 26, 2019 Page 6 of 8
not met in the existing plus project condition. The Peak Hour traffic signal warrant results are shown
in Attachment 1.
Multimodal Site Access & Circulation
Multimodal site access and circulation was qualitatively assessed based on Project site plans. The
Project driveway is situated at the western side of the site, which maximizes horizontal separation
from the Forbes Boulevard / Allerton Avenue intersection, lessening potential conflicts between
vehicle movements at the driveway and intersection. The driveway is 26-feet wide, which permits
entry and exit for automobiles and small single-unit trucks with minimal potential for conflicts with
opposing vehicles. Sight lines are not impeded for drivers exiting the Project site, but City staff or
other qualified professionals should verify adequate sight lines are maintained as the site design
progresses.
As noted previously, Forbes Boulevard features a center median which alternates between a two-
way left turn lane and landscaped islands. An existing landscape island impedes inbound motor
vehicle access to the Project site for motorists approaching from the west. Since most inbound trips
are anticipated to approach the site from this direction, the median could be modified to permit
left turns from Forbes Boulevard into the Project site.
Recommendation #1: Modify the existing landscape island within the Forbes Boulevard
center median to permit left turns for motorists approaching the site on Forbes Boulevard
from the west. The extent of the potential modification is depicted in Figure 3. If desired
by City officials or the Project Team, an existing gap within the landscape median to the
west of the site driveway could be replaced with landscaping to lessen, equal, or exceed
the net landscape area removed.
The parking lot drive aisles and parking stall dimensions appear to meet City design standards for
parking facilities and general engineering design principles. The alignment of drive aisle
approaching the proposed parking garage structure could be shifted to minimize sharp turns and
reduce turning friction.
Recommendation #2: Consider modifying the lane geometry or alignment of the drive
aisle approaching the parking garage. The angle and adjacent parking stalls could
introduce conflicts between drivers accessing the surface parking stalls and drivers
accessing the garage. At minimum, stripe the drive aisle centerline to guide drivers through
the corner.
Mr. Colum Regan June 26, 2019 Page 7 of 8
We assessed commercial motor vehicle access using AutoTURN, a swept-path vehicle simulation
tool that shows maneuvering space required for various design vehicles. We tested access for an
SU-30 design vehicle per the specifications of the Project sponsor. The results are shown on Figure
4 The SU-30 can back into the proposed loading dock (albeit with some challenging maneuvering),
and can turn around on site, avoiding backing maneuvers into Forbes Boulevard. Drive aisles and
driveways provide adequate maneuvering space for the trucks to enter and depart the site.
Pedestrian access is provided via a proposed walkway adjacent to the driveway that connects to an
existing sidewalk along Forbes Boulevard. As part of the project, the existing driveway along the
eastern edge of the Project site is to be removed, providing an opportunity to enhance pedestrian
connectivity at the intersection of Forbes Boulevard and Allerton Avenue with a new marked
pedestrian crosswalk on the western leg of the intersection. This location would be suitable for a
shuttle stop for Commute.org or another operator as appropriate.
Recommendation #3: With removal of the existing driveway at the eastern edge of the
Project site, install a new marked, high-visibility crosswalk on the western leg of the Forbes
Boulevard / Allerton Avenue intersection. Install a curb ramp and accessibility
improvements as required to formalize pedestrian crossing at this location. If a shuttle stop
is desired, the sidewalk should be widened to at least 8-feet to meet bus stop accessibility
standards at the boarding location. A shelter and bench could further enhance the quality
of the shuttle stop. The approximate extents of these enhancements are shown in Figure
3.
Bicycle access would be either shared with the Project driveway or via the adjacent walkway. Based
on the City of South San Francisco’s Bicycle Master Plan, a Class I bicycle and pedestrian shared-
used trail is envisioned along the former railroad spur that fronts the rear edge of the project site.
The Project would also not preclude a future extension of Class II buffered bicycle lanes on Forbes
Boulevard, which may be funded by the Project’s Bicycle and Pedestrian Impact Fees and other
sources.
Off-Street Parking Supply
Based on the City of South San Francisco’s zoning code, off-street automobile and bicycle parking
minimums apply to the Project. At least one automobile parking stall is required per 350 square
feet of gross floor area for research and development or professional office uses over 100,000
square feet. Based on plans dated February 25, 2019, 368 parking stalls are proposed as part of the
Mr. Colum Regan June 26, 2019 Page 8 of 8
Project, and 371 are required. Additional parking stalls may be required. However, the project’s
required TDM trip reduction of 35 percent may support a reduction in parking supply at the
discretion of City officials.
Long-term bicycle parking spaces, such as lockers or other secure facilities are also required. Based
on the zoning code, long-term bicycle parking, such as lockers or other secure bicycle parking
facilities, shall be provided at a ratio of one space per 25 vehicle spaces. At least 15 long-term
bicycle parking spaces are required as part of the Project.
Recommendation #4: Verify off-street auto parking requirements with City staff as
exemptions and adjustments may apply for the Project’s TDM requirements. Provide at
least 15 long term bicycle parking spaces that meet design and performance standards in
the City’s Municipal Code, Chapter 20.330.008.
493 Forbes BoulevardOff-Site Roadway ImprovementsFigure 3N.T.S.CONCEPTUAL - NOT FOR CONSTRUCTION. ADDITIONALDETAILED ANALYSIS AND ENGINEERING DESIGN REQUIRED.
493 Forbes BoulevardOff-Site Roadway ImprovementsFigure 4N.T.S.CONCEPTUAL - NOT FOR CONSTRUCTION. ADDITIONALDETAILED ANALYSIS AND ENGINEERING DESIGN REQUIRED.SU-30 Truck Turning Movements
Project 493 Forbes Boulevard
Major Street Forbes Boulevard Scenario Existing
Minor Street Allerton Avenue Peak Hour AM
Turn Movement Volumes Major Street Direction
NB SB EB WB
Left 62 6 22 109 North/South
Through 5 7 430 138 x East/West
Right 78 11 86 5
Total 145 24 538 252
Major Street Minor Street Warrant MetForbes Boulevard Allerton Avenue
1 1 NONumber of Approach Lanes
* Note: Traffic Volume for Major Street is Total Volume of Both Approches.
Traffic Volume for Minor Street is the Volume of High Volume Approach.
Traffic Volume (VPH) *790 145
0
100
200
300
400
500
600
400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800
Minor Street Higher Volume Approach - VPH
Major Street -Total of Both Approaches -Vehicle Per Hour (VPH)
Warrant 3B, Peak Hour
* Note: 150 vph applies as the lower threshold volume for a minor-street
approach with two or more lanes and 100 vph applies as the lower
threshold volume for a minor-street approach with one lane.
Source: California Manual on Uniform Traffic Control Devices, Caltrans, 2014
150*
100*
2 or More Lanes & 2 or More Lanes
1 Lane & 1 Lane
2 or More Lanes & 1 Lane
Attachment 1
Project 493 Forbes Boulevard
Major Street Forbes Boulevard Scenario Existing + Project
Minor Street Allerton Avenue Peak Hour AM
Turn Movement Volumes Major Street Direction
NB SB EB WB
Left 68 6 22 109 North/South
Through 5 7 432 152 x East/West
Right 78 11 87 5
Total 151 24 541 266
Major Street Minor Street Warrant MetForbes Boulevard Allerton Avenue
1 1 NONumber of Approach Lanes
* Note: Traffic Volume for Major Street is Total Volume of Both Approches.
Traffic Volume for Minor Street is the Volume of High Volume Approach.
Traffic Volume (VPH) *807 151
0
100
200
300
400
500
600
400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800
Minor Street Higher Volume Approach -VPHMajor Street -Total of Both Approaches -Vehicle Per Hour (VPH)
Warrant 3B, Peak Hour
* Note: 150 vph applies as the lower threshold volume for a minor-street
approach with two or more lanes and 100 vph applies as the lower
threshold volume for a minor-street approach with one lane.
Source: California Manual on Uniform Traffic Control Devices, Caltrans, 2014
150*
100*
2 or More Lanes & 2 or More Lanes
1 Lane & 1 Lane
2 or More Lanes & 1 Lane
Project 493 Forbes Boulevard
Major Street Forbes Boulevard Scenario Existing
Minor Street Allerton Avenue Peak Hour PM
Turn Movement Volumes Major Street Direction
NB SB EB WB
Left 67 5 13 59 North/South
Through 8 13 120 413 x East/West
Right 65 27 28 5
Total 140 45 161 477
Major Street Minor Street Warrant MetForbes Boulevard Allerton Avenue
1 1 NONumber of Approach Lanes
*Note: Traffic Volume for Major Street is Total Volume of Both Approches.
Traffic Volume for Minor Street is the Volume of High Volume Approach.
Traffic Volume (VPH) *638 140
0
100
200
300
400
500
600
400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800
Minor Street Higher Volume Approach - VPH
Major Street -Total of Both Approaches -Vehicle Per Hour (VPH)
Warrant 3B, Peak Hour
* Note: 150 vph applies as the lower threshold volume for a minor-street
approach with two or more lanes and 100 vph applies as the lower
threshold volume for a minor-street approach with one lane.
Source: California Manual on Uniform Traffic Control Devices, Caltrans, 2014
150*
100*
2 or More Lanes & 2 or More Lanes
1 Lane & 1 Lane
2 or More Lanes & 1 Lane
Project 493 Forbes Boulevard
Major Street Forbes Boulevard Scenario Existing + Project
Minor Street Allerton Avenue Peak Hour PM
Turn Movement Volumes Major Street Direction
NB SB EB WB
Left 68 5 13 59 North/South
Through 8 13 133 415 x East/West
Right 65 27 33 5
Total 141 45 179 479
Major Street Minor Street Warrant MetForbes Boulevard Allerton Avenue
1 1 NONumber of Approach Lanes
*Note: Traffic Volume for Major Street is Total Volume of Both Approches.
Traffic Volume for Minor Street is the Volume of High Volume Approach.
Traffic Volume (VPH) *658 141
0
100
200
300
400
500
600
400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800
Minor Street Higher Volume Approach - VPH
Major Street -Total of Both Approaches -Vehicle Per Hour (VPH)
Warrant 3B, Peak Hour
* Note: 150 vph applies as the lower threshold volume for a minor-street
approach with two or more lanes and 100 vph applies as the lower
threshold volume for a minor-street approach with one lane.
Source: California Manual on Uniform Traffic Control Devices, Caltrans, 2014
150*
100*
2 or More Lanes & 2 or More Lanes
1 Lane & 1 Lane
2 or More Lanes & 1 Lane