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January 10, 2023
Project No. 622114
Adrianne Carr, Ph.D.
General Manager
North Coast County Water District
2400 Francisco Blvd
Pacífica, CA 94044
T: 650-3553462
E: [email protected]
RE: NORTH COAST COUNTY WATER DISTRICT HEADQUARTERS
PROJECT TRAFFIC EVALUATION
PACIFICA, CA
Dear Adrianne,
At the request of the North Coast County Water District (District), we have performed a traffic evaluation for the new District Headquarters. This evaluation focuses on the following specific elements:
• Evaluation of Francisco Blvd / Brighton Rd including an All-way Stop Control Warrant • Roadway / Parking Layout of Francisco Blvd along Headquarters frontage The following report presents the evaluation and resulting findings / recommendations for each of the two elements.
All Way Stop Warrant
Primary Warrants
The California Manual on Uniform Traffic Control Devices (CAMUTCD) Section 2B.07 provides a set of guidelines that can be used to determine the appropriateness of installing an all-way stop condition at an intersection. The primary warrants listed for installing all-way stop control include:
A. Where traffic control signals are justified, the multi-way stop is an interim measure that can be installed quickly to control traffic while arrangements are being made for the installation of the traffic control signal.
B. Five or more reported crashes in a 12-month period that are susceptible to correction by a multi-way stop installation. Such crashes include right-turn and left-turn collisions as well as right-angle collisions.
C. Minimum volumes:
1. The vehicular volume entering the intersection from the major street approaches (total of both approaches) averages at least 300 vehicles per hour for any 8 hours of an average day; and
2. The combined vehicular, pedestrian, and bicycle volume entering the intersection from the minor street approaches (total of both approaches) averages at least 200 units per hour for the same 8 hours, with an average delay to minor-street vehicular traffic of at least 30 seconds per vehicle during the highest hour; but
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3. If the 85th-percentile approach speed of the major-street traffic exceeds 40 mph, the minimum vehicular volume warrants are 70 percent of the values provided in Items 1 and 2.
D. Where no single criterion is satisfied, but where Criteria B, C.1, and C.2 are all satisfied to 80 percent of the minimum values. Criterion C.3 is excluded from this condition.
Primary Warrant A (Interim Condition)
Primary Warrant A is specifically targeted toward intersections where signalization is either under consideration or is already planned for future installation. Signalization has not been planned or considered at the project intersection meaning Primary Warrant A is not applicable.
Primary Warrant B (Crash History)
The crash history warrant is aimed at reducing the frequency of crashes at an intersection via the installation of all-way stop control. To analyze this warrant, collision records for a five-year period (01/01/2018- 01/01/2023) were collected from the California Highway Patrol’s (CHP) Statewide Integrated Traffic Records System (SWITRS). Between 2018 and 2023 there were three collisions recorded at the intersection including two sideswipes with a parked vehicle and one collision with a fixed object. None of these collision types are considered to be susceptible to correction by a multi-way stop installation. The frequency of crashes is also far below the five crashes within a 12-month period threshold specified in the warrant. For this reason, Primary Warrant B was not satisfied.
Primary Warrant C (Minimum Volumes)
Primary Warrant C analyzes whether traffic volumes and/or vehicle delay warrant the installation of all-way stop control.
Traffic counts were collected on 08/03/22 (Wednesday) from 7:00AM-9:00AM and 4:00PM-6:00PM. This was assumed to capture the peak AM and PM traffic volume periods respectively at the intersection. These counts were utilized to analyze minimum traffic volumes. The full traffic count data can be found in the appendix of this report.
From the combined 4 hours of AM and PM peak period data, the average hourly traffic along Francisco Blvd (both directions) was found to be 194 veh/hr. This is below the required 300 veh/hr threshold. Additionally, because the collected data represents the peak period traffic conditions, it was assumed that traffic volumes outside of this range are also at or below 194 veh/hr. As a result, Primary warrant C.1 was not satisfied.
Primary Warrant C.1 and C.2 must both be met to be satisfied. Because Primary Warrant C.1 was not satisfied, Primary Warrant C.2 was not analyzed.
The 85th percentile speed along Francisco Blvd was determined to be 32 mph. Primary Warrant C.3 was found not applicable because the 85th percent speed is below the 40 MPH threshold of Warrant C.3.
Primary Warrant D (Combined Criteria)
Primary Warrant D pertains to Primary Warrant B and C being satisfied in combination while only requiring each to meet 80% of their stated values.
For Primary Warrant B, the 80% value equates to 4 crashes within a 12-month period. For the highest frequency 12-month period only 2 crashes were reported at the intersection, both of which are not considered to be susceptible to correction by a multi-way stop installation. As a result, Primary Warrant D was deemed to be not applicable, and it was not necessary to reanalyze Primary Warrant C to 80% values.
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Optional Warrants
Section 2B.07 of the CAMUTCD also lists several optional considerations including:
A. The need to control left-turn conflicts;
B. The need to control vehicle/pedestrian conflicts near locations that generate high pedestrian volumes;
C. Locations where a road user, after stopping, cannot see conflicting traffic and is not able to negotiate the intersection unless conflicting cross traffic is also required to stop; and D. An intersection of two residential neighborhood collector (through) streets of similar design and operating characteristics where multi-way stop control would improve traffic operational characteristics of the intersection.
Optional Warrant A (Left-Turn Conflicts)
All-way stop control may be warranted at an intersection if there are significant left-turn conflicts. SWITRS crash history for the five-year period was consulted to determine if there appears to be any left turn conflict present at the intersection. Over the five-year period, none of the reported crashes involved a left turn movement. For this reason, Optional Warrant A was not deemed to be satisfied.
Optional Warrant B (Vehicle/Pedestrian Conflicts)
Optional Warrant B examines whether there are significant pedestrian conflicts across the uncontrolled approaches of the intersection. There are no crosswalks across Francisco Blvd and no pedestrian destinations on the east side of Francisco Blvd to generate any crossing pedestrian traffic. Optional Warrant B was deemed not satisfied because there does not appear to be a significant pedestrian conflict for the currently uncontrolled Francisco Blvd approaches.
Optional Warrant C (Line of Sight)
Optional Warrant C examines whether line-of-sight limitations restrict a driver’s ability to navigate the intersection and avoid conflicting vehicle traffic safely. Because the Francisco Blvd approaches are uncontrolled, and the Brighton Rd approach is stop controlled the only condition analyzed was drivers entering the intersection from the Brighton Rd approach.
The California Department of Transportation’s (Caltrans) Highway Design Manual (HDM) section 405.1 provides guidance regarding intersection Corner sight distance.
The 85th percentile speed (32 MPH) was used as the design speed and the design vehicle was assumed to be a passenger vehicle.
The HDM methodology resulted in the required sight distance to be 305’ for vehicles approaching from the left on SB Francisco Blvd and 355’ for vehicles approaching from the right on NB Francisco Blvd. However, the allway stop-controlled intersection of Clarendon Rd and Francisco Blvd is only 240’ from the decision point at the project intersection. Because all vehicles come to a complete stop at the Clarendon Rd and Francisco Blvd intersection, it was assumed that the line of sight only needs to extend to the edge of this intersection (240’).
Exhibit 1 shows the resulting line of sight with the proposed site development shown for reference. For vehicles to safely enter uncontrolled Francisco Blvd, 215’ of clear space is required along the curb line to the north of the intersection and 100’ of clear space is required along the curb line to the south of the intersection.
This would result in the removal of approximately six existing parallel parking spaces to the north of the BUILD ON. | 4
intersection and approximately three proposed parallel parking stalls to the south of the intersection.
Removing this parking would require public outreach and is assumed to receive community pushback. The line of sight is not sufficient without the removal of parking and would require additional analysis and outreach. Optional warrant C is considered to be satisfied due to the line-of-sight limitations as this project does not propose to remove or limit existing roadway parking.
Optional Warrant D (Intersection of Two Collectors)
Optional Warrant D examines locations where two similar Residential collector roadways intersect. According to the City of Pacifica General plan dated May 2022, Francisco Blvd is classified as a collector, and Brighton Rd is classified as a local street. Because Brighton Rd is not a collector or through street, Optional Warrant D is not satisfied.
Summary and Recommendations
Table 1 summarizes the results of each All-Way Stop Control warrant that was examined. Optional Warrant C (Line of Sight) was found to be satisfied due to line-of-sight limitations. Given our understanding of parking demand near the Project extents, review of the surrounding roadway / traffic environment and Optional Warrant C being satisfied, we recommend all-way stop control be implemented at the Francisco Blvd and Brighton Rd intersection.
Table 1: All-Way Stop Warrant Results
Primary Warrants
Letter Criteria Satisfied
A Interim Condition (Before Signalization) Not Applicable B Crash History No
C.1 Major Street Volumes No
C.2 Minor Street Volumes No
C.3 Reduced Thresholds for Roadways Exceeding 40 MPH Travel Speeds Not Applicable
D Combined 80% Criteria for B, C.1 & C.2 together (C.3 not applicable) No
Optional Warrants
Letter Criteria Satisfied
A Left-Turn Conflicts No
B Vehicle/Pedestrian Conflicts No
C Line of Sight Yes
D Intersection of two Residential Collectors (through) Streets Not Applicable BUILD ON. | 5
Francisco Boulevard Parking / Lane Configuration
Overview
The proposed District Headquarters project intends to improve the project frontages along Francisco Blvd, Clarendon Rd and Brighton Rd. As part of these improvements, new sidewalk/landscaping will be constructed along with parking facilities adjacent to the roadway. The project is currently proposing parallel parking along the Clarendon and Brighton Rd frontages and a combination of parallel and diagonal parking along the Francisco Blvd frontage.
As part of this study, Sandis evaluated the overall roadway layout on Francisco to determine whether diagonal parking is feasible within the current roadway extents of Francisco Blvd. The proposed layout shows a 4.8 ft wide sidewalk, 19.9 ft wide 45-degree parking area, and 12 ft wide lanes in both the northbound and southbound directions. In order to determine if this configuration is adequate from a circulation standpoint, Sandis performed an analysis using the Autoturn program. Refer to Exhibit 2, Diagonal Parking Exhibit, which shows the movement of a vehicle exiting one of the diagonal stalls and then traveling southbound on Francisco Blvd. As indicated on, a vehicle can stay within the southbound lane extents when backing out and turning to travel southbound.
Summary and Recommendations
Based on our review of the proposed parking and travel lane layout, we believe that the diagonal parking configuration is acceptable and does not create a safety concern. Maintaining the 12 ft wide travel lanes and installing a center lane stripe will promote traffic calming and encourage vehicles to travel at slower speeds between the Brighton and Clarendon Rd intersections.
Please contact me at [email protected] with any questions or should you require additional information.
Regards,
Ronald Sanzo, PE, TE, PTOE
Director of Engineering
Attachments: Traffic Count Data, Exhibit 1 – Line of Sight Exhibit, Exhibit 2 – Diagonal Parking Exhibit Prepared by National Data & Surveying Services
ID: 22-080222-001 Day:
City: Pacifica Date:
AM 2 88 0 0 AM
NOON 0000 NOON
PM 8 185 0 0 PM
AM NOON PM PM NOON AM
0000 0 000
0 000
000 00 000
404 0 TEV 149 0 330 0 000
000 0 PHF 0.83 0.90
3 0 11 0 0000
AM NOON PM PM NOON AM
PM 0 8 114 0 PM
NOON 0000 NOON
AM 0 4 48 0 AM
0 NONE
05:00 PM - 06:00 PM 118
Francisco Blvd & Brighton Rd
Peak Hour Turning Movement Count
Francisco Blvd Wednesday
SOUTHBOUND 8/3/2022
PEAK HOURS
4:00 PM - 06:00 PM
08:00 AM - 09:00 AM 52 7:00 AM - 09:00 AM
COUNT PERIODS
NONE
000
Totals (AM) 196 Total Bikes (AM)
Brighton Rd
EASTBOUND
WESTBOUND
Brighton Rd
6 0 16
CONTROL
1-Way Stop(EB)
Pedestrians (Crosswalks)
Totals (PM) Total Bikes (PM)
0 91
NORTHBOUND
Francisco Blvd
Totals (NOON) Total Bikes (NOON)
AM NOON PM
PM
AM
AM
NOON
PM
PM
NOON
AM
AM
NOON
PM
NOON
PMNOONAMAMNOONPM
PMNOONAMAMNOONPM
1 0
6 1
0 2
00 000
0 0
0 0
0 0
0 00 000 0
0 0
1 0
0 0
000
000
0 0
0 0
0 0
000
000
0 0
0 0
0 0
010
000
0 0
11 0
0 4
81850
81140
0 0
0 0
0 0
000
000
0 0
3 0
0 4
2880
4480
National Data & Surveying ServicesIntersection Turning Movement Count Location: Francisco Blvd & Brighton Rd
City: Pacifica Project ID:
Control: 1-Way Stop(EB) Date:
NS/EW Streets:
0000000000000000
NL NT NR NU SL ST SR SU EL ET ER EU WL WT WR WU TOTAL
7:00 AM 0200061010100000 11
7:15 AM 0000031010000000 5
7:30 AM 1 4 0 0 0 11 0 0 0 0 4 0 0 0 0 0 20
7:45 AM 1 3 0 0 0 10 2 0 0 0 0 0 0 0 0 0 16
8:00 AM 2 14 0 0 0 22 2 0 3 0 2 0 0 0 0 0 45
8:15 AM 0 14 0 0 0 29 0 0 0 0 0 0 0 0 0 0 43
8:30 AM 1 8 0 0 0 22 0 0 0 0 0 0 0 0 0 0 31
8:45 AM 1 12 0 0 0 15 0 0 1 0 1 0 0 0 0 0 30
NL NT NR NU SL ST SR SU EL ET ER EU WL WT WR WU TOTAL
TOTAL VOLUMES : 6 57 0 0 0 118 6 0 6 0 8 0 0 0 0 0 201
APPROACH %'s : 9.52% 90.48% 0.00% 0.00% 0.00% 95.16% 4.84% 0.00% 42.86% 0.00% 57.14% 0.00% PEAK HR : 08:00 AM 41 0 0 TOTAL
PEAK HR VOL : 4 48 0 0 0 88 2 0 4 0 3 0 0 0 0 0 149
PEAK HR FACTOR : 0.500 0.857 0.000 0.000 0.000 0.759 0.250 0.000 0.333 0.000 0.375 0.000 0.000 0.000 0.000 0.000 Headers NBL NBT NBR NBU SBL SBT SBR SBU EBL EBT EBR EBU WBL WBT WBR WBU 0000000000000000
NL NT NR NU SL ST SR SU EL ET ER EU WL WT WR WU TOTAL
4:00 PM 2 25 0 0 0 44 2 0 0 0 1 0 0 0 0 0 74
4:15 PM 2 25 0 0 0 40 1 0 1 0 2 0 0 0 0 0 71
4:30 PM 2 25 0 0 0 35 0 0 0 0 2 0 0 0 0 0 64
4:45 PM 1 24 0 0 0 44 2 0 2 0 0 0 0 0 0 0 73
5:00 PM 1 29 0 0 0 55 2 0 2 0 3 0 0 0 0 0 92
5:15 PM 2 30 0 0 0 54 1 0 1 0 2 0 0 0 0 0 90
5:30 PM 4 17 0 0 0 34 4 0 0 0 5 0 0 0 0 0 64
5:45 PM 1 38 0 0 0 42 1 0 1 0 1 0 0 0 0 0 84
NL NT NR NU SL ST SR SU EL ET ER EU WL WT WR WU TOTAL
TOTAL VOLUMES : 15 213 0 0 0 348 13 0 7 0 16 0 0 0 0 0 612 APPROACH %'s : 6.58% 93.42% 0.00% 0.00% 0.00% 96.40% 3.60% 0.00% 30.43% 0.00% 69.57% 0.00% PEAK HR : 05:00 PM 293 0 0 TOTAL
PEAK HR VOL : 8 114 0 0 0 185 8 0 4 0 11 0 0 0 0 0 330
PEAK HR FACTOR : 0.500 0.750 0.000 0.000 0.000 0.841 0.500 0.000 0.500 0.000 0.550 0.000 0.000 0.000 0.000 0.000 22-080222-001
8/3/2022
05:00 PM - 06:00 PM
0.897 0.782 0.846 0.750
08:00 AM - 09:00 AM
0.828
PM NORTHBOUND SOUTHBOUND EASTBOUND WESTBOUND
0.813 0.776 0.350
AM NORTHBOUND SOUTHBOUND EASTBOUND WESTBOUND
Data - Totals
Francisco Blvd Francisco Blvd Brighton Rd Brighton Rd
Day: City: Pacifica
Date: Project #: CA22_080223_001
Time < 15 15 ‐ 19 20 ‐ 24 25 ‐ 29 30 ‐ 34 35 ‐ 39 40 ‐ 44 45 ‐ 49 50 ‐ 54 55 ‐ 59 60 ‐ 64 65 ‐ 69 70 + Total 00:00 AM 2025200000000 11
01:00 0003402000000 9
02:00 0014200000000 7
03:00 0005100000000 6
04:00 1010210000000 5
05:00 2 1 2 12 6 2 0 0 0 0 0 0 0 25
06:00 7 3 8 20 7 0 0 0 0 0 0 0 0 45
07:00 15 4 13 21 25 1 1 0 0 0 0 0 0 80
08:00 10 4 31 28 27 8 1 0 0 0 0 0 0 109
09:00 14 5 21 64 28 3 0 0 0 0 0 0 0 135
10:00 11 4 44 76 38 4 0 0 0 0 0 0 0 177
11:00 17 5 53 88 37 2 1 0 0 0 0 0 0 203
12:00 PM 11 9 38 85 48 5 0 0 0 0 0 0 0 196
13:00 17 9 45 78 39 5 0 0 0 0 0 0 0 193
14:00 11 7 52 73 47 5 3 0 0 0 0 0 0 198
15:00 14 11 50 105 47 1 0 0 0 0 0 0 0 228
16:00 9 10 78 123 52 8 3 0 0 0 0 0 0 283
17:00 16 17 66 131 66 3 0 0 0 0 0 0 0 299
18:00 12 4 44 122 52 1 0 0 0 0 0 0 0 235
19:00 7 6 30 74 44 11 0 0 0 0 0 0 0 172
20:00 3 2 25 54 31 3 0 0 0 0 0 0 0 118
21:00 1 2 15 39 10 4 0 0 0 0 0 0 0 71
22:00 0 0 8 20 3 4 0 0 0 0 0 0 0 35
23:00 1029810000000 21
181 103 629 1239 626 72 11 2861
6% 4% 22% 43% 22% 3% 0% 100%
79 26 176 326 179 21 5 0 0 0 0 0 0 812
3% 1% 6% 11% 6% 1% 0% 28%
11:00 09:00 11:00 11:00 10:00 08:00 01:00 11:00 17 5 53 88 38 8 2 203
102 77 453 913 447 51 6 0 0 0 0 0 0 2049
4% 3% 16% 32% 16% 2% 0% 72%
13:00 17:00 16:00 17:00 17:00 19:00 14:00 17:00
17 17 78 131 66 11 3 299
AM 7‐9 NOON 12‐2 PM 4‐6 Off Peak Volumes
Volume % Volume % Volume % Volume %
189 7% 389 14% 582 20% 1701 59%
Summary
ADT
2861
Percentiles Street Name
Francisco Blvd
85th
32 95th
35 50th
27 Average
26 15th Direction
21 Prepared by National Data & Surveying Services
SPEED
Francisco Blvd N/O Brighton Rd
8/3/2022
Summary
Totals
% of Totals
AM Volumes
% AM
AM Peak Hour
All Speeds
Wednesday
Volume
PM Volumes
% PM
PM Peak Hour
Volume
Directional Peak Periods
NO PARKING
0'
1 INCH =
8' 20' 40' 80'
40 FT
0'
1 INCH =
4' 10' 20' 40'
20 FT
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