1 TO: City Council
FROM: Ryan Smoot, City Manager
PREPARED BY: Carla Dillon, P.E., Director of Public Works MEETING DATE: July 18, 2023
SUBJECT: Discussion of Lane Striping on Narbonne Avenue South of Pacific Coast Highway
RECOMMENDATION:
Discussion only.
BACKGROUND:
In 2017, following a County evaluation, the City Council approved changes to restripe Narbonne Avenue to its current configuration from the northern city boundary to just north of Pacific Coast Highway (PCH) in conjunction with a street pavement project (Figure 1).
In addition, the city’s Bicycle and Pedestrian Master Plan, adopted as a guidance document by the City Council in March 2018, calls for the lane reconfiguration on the southern portion of Narbonne Ave to allow for one driving lane in each direction, a center turn lane, two 6’ bike lanes, and parking on each side. The existing striping pattern, south of PCH is shown on Figure 2.
While the City is in the design phase of a street reconstruction project for Narbonne Avenue south of PCH, decisions need to be made prior to finalizing the plans as the pavement substructure design may vary for a traffic lane versus a parking or bike lane.
The change in 2017, with a single lane in each direction with the center turn lane, provided benefits to ease traffic concerns north of Pacific Coast Highway, and the city’s Technical Traffic Advisory Committee has received concerns with speed, visibility, and parking along the section of Narbonne Avenue that remains in its original striping pattern.
Item No. SCH 8b
CITY OF LOMITA
CITY COUNCIL REPORT
2 Striping North of PCH (Fig. 1) Striping South of PCH (Fig. 2) The Public Safety and Traffic Commission reviewed this proposed striping plan on June 21, 2023, and recommended the change to one driving lane in each direction. In addition, the Commission requested that staff consider angled parking on this segment of Narbonne Avenue to relieve parking congestion in the area. The City’s consultant reviewed the street width and determined that even with one side of angled parking and the other side with parallel parking, the street does not provide enough width for a driving lane in each direction, a center turn lane, and bicycle lanes.
Staff is seeking Council’s direction on the proposed restriping so the City’s design consultant can complete the pavement design. The final drawings and bid package will be presented to the City Council for approval prior to awarding the contract for construction. The final design will incorporate details, such as right turn lane pocket and no parking within a certain distance from the intersection. 3 FISCAL IMPACT
None at this time.
OPTIONS
1. Provide input on striping plan
ATTACHMENT
1. 2017 Restriping Report from LA County
2. 2023 Traffic Assessment
Reviewed by: Approved by:
Gary Y. Sugano Ryan Smoot
Assistant City Manager City Manager
Prepared by:
Carla Dillon, PE
Public Works Director
July 27, 2017
TO: Mark McAvoy, Public Works Director
City of Lomita
FROM: Irena Guilmette
Traffic Advisor
CONSIDERATION OF A REQUEST TO RESTRIPE NARBONNE AVENUE BETWEEN
PACIFIC COAST HIGHWAY AND LOMITA BOULEVARD
At the March 7, 2017, Lomita City Council Meeting, the Council was presented with a proposal to restripe a portion of Narbonne Avenue between Pacific Coast Highway and Lomita Boulevard. This roadway reconfiguration was to be completed due to the upcoming pavement rehabilitation project on Narbonne Avenue that is slated to begin construction soon. After hearing the Staff report, the City Council made a motion to continue this matter after a more comprehensive traffic study was conducted by Los Angeles County.
Existing Conditions
This segment of Narbonne Avenue is classified as a minor arterial roadway on the 2013 Functional Classification System’s California Road System maps on file with the Federal Highway Administration. It is an undivided highway striped for two lanes of travel in each direction with on-street parking. The roadway has curb, gutter and sidewalk on both sides.
Narbonne Avenue is signalized at Lomita Boulevard, 250th Street, 255th Street and Pacific Coast Highway. Between Lomita Boulevard and 250th Street, the abutting property consists of commercial and residential properties with the Lomita Magnet Elementary School located on the northwest corner of 247th Street and Narbonne Avenue. Between 250th Street and Pacific Coast Highway, there is a mix of commercial, multiple-dwelling residential and singlefamily residential development. The 0.90 mile Narbonne Avenue corridor between Pacific Coast Highway and Lomita Boulevard has a posted speed limit of 35 miles per hour (mph), and the average daily traffic is approximately 14,300 vehicles per day.
Proposed Conditions
This roadway reconfiguration would reallocate road space to one lane in each direction, a center two-way left-turn lane, a Class II bicycle lane in each direction with parking to remain on both sides of the roadway. The striping at the signalized intersections of Narbonne Avenue at 250th Street and 255th Street would transition the two-way left turn lanes into dedicated left turn lanes for both northbound and southbound Narbonne Avenue. The striping at the signalized intersection of Lomita Boulevard would remain the same except for the extension of the northbound left turn lane and the addition of dedicated right turn lanes on Lomita Boulevard. The existing striping at the signalized intersection of Pacific Coast Highway would remain the same. Traffic signal timing on Narbonne Avenue at the signalized intersections would need to be modified to accommodate the reconfigured roadway.
Traffic Analysis Methodology
The County of Los Angeles considers any roadway with less than 20,000 vehicles per day to be an ideal lane reconfiguration candidate and a roadway with less than 15,000 vehicles Attachment 1
per day wouldn’t require a level of service (LOS) analysis. Although Narbonne Avenue has less than 15,000 vehicles per day, for purposes of this study, the County conducted a LOS analysis at the intersection of Narbonne Avenue and Lomita Boulevard due to traffic concerns raised by the public at the March 7, 2017, City of Lomita Council Meeting. Based on the analysis, LOS ratings ranging from A through F were assigned to this intersection, with A representing free flow, and F representing congested conditions. The following table represents the LOS for the intersection of Narbonne Avenue at Lomita Boulevard:
Intersection
Narbonne Avenue
at
Lomita Boulevard
Peak Existing
Conditions
(2016)
Existing
Conditions
(2035)
Project
Conditions
(2016)
Project
Conditions
(2035)
LOS V/C LOS V/C LOS V/C LOS V/C
AM D 0.85 D 0.88 C 0.81 D 0.84
PM E 0.97 F 1.01 E 0.91 E 0.95
Indicates inadequate northbound and southbound left-turn lane storage capacity Indicates adequate northbound and southbound left-turn lane storage capacity
According to the County’s General Plan, acceptable LOS is considered on a case-by-case basis with LOS D generally being the minimum desired. LOS ratings below D may be acceptable according to the County’s General Plan if the project supports the General Plan goals, such as creating an efficient multimodal transportation system that serves the needs of all residents, and promoting active transportation.
Based on the analysis, the intersection studied was categorized into the following groupings:
LOS A through D
Implementation of roadway configuration is not expected to result in traffic congestion at this intersection.
LOS E
Implementation of roadway reconfiguration is expected to result in traffic congestion at this intersection. However, LOS ratings below D may be acceptable according to the County's General Plan if the project supports the General Plan goal of promoting active transportation. The benefits, if implemented, should outweigh the traffic congestion impacts at this intersection.
LOS F with Adequate Turn-Lane Capacity
Implementation of roadway reconfiguration is expected to result in severe traffic congestion at this intersection. However, turn-lane capacities are adequate to accommodate the forecasted queue lengths. The benefits, , if implemented, should substantially outweigh the traffic congestion impacts at this intersection.
LOS F with Inadequate Turn-Lane Capacity
Implementation of roadway reconfiguration is expected to result in severe traffic congestion at this intersection. Furthermore, extending the length of the turn-lanes to accommodate the forecasted queue is not feasible due to site-specific constraints.
Implementation of roadway reconfiguration is not advisable along the roadways approaching this intersection.
No Change to LOS
For purposes of analysis, the intersection configuration is not expected to change at this location. Lane configurations from roadway reconfiguration will transition to join existing striping conditions approaching this intersection.
Although the LOS at the intersection of Narbonne Avenue at Lomita Boulevard shows a LOS of E during the PM peak hours, the northbound and southbound left-turn capacity goes from inadequate to adequate with the intersection lane changes.
Benefits of lane reconfiguration along Narbonne Avenue
Pedestrians
● Pedestrian crossing of Narbonne Avenue may be easier and safer due to a reduction in the number of lanes to cross which reduces potential conflicts between pedestrians and vehicles.
Bicyclists
● Increase in Active Transportation by providing bike lanes which meets the goals of Complete Streets and Healthy Design.
● Increase in the safety and comfort of bicyclists by providing a striped space on the roadway. The National Association of City Transportation Officials (NACTO) advocates the benefits of bike lanes, including increased bicyclist comfort and confidence on busy streets, separation between bicyclists and automobiles, increased predictability of bicycles and motorists positioning and interaction, increased total capacities of streets carrying mixed bicycle and motor vehicle traffic and a visual reminder to motorists of bicyclists’ right to the street.
Emergency Vehicles
● Adding a 2-way left-turn lane would create unimpeded lanes that can be used by emergency vehicles or motorists needing to pull over to provide through movement of emergency responders.
Motorists
● Reduce specific types of traffic collisions. Per the U.S. Department of Transportation Federal Highway Administration, roadway configurations such as this may have a crash reduction of 19 percent on corridors within suburban areas surrounding larger cities.
● Reduce intersection conflicts.
● Enhance intersection sight distance.
● Reduces left-turn conflicts at intersections and midblock locations. ● Reduce vehicle travel speeds because having additional lanes during non-peak hours encourages people to speed.
● Provide continuous turning lanes for left-turning vehicles which may potentially reduce mid-block delay and weaving.
Community
● Improve business because people who walk or use bikes spend more money.
Cost-Effective
● Implementing roadway design during the upcoming pavement rehabilitation project on Narbonne Avenue is cost-effective because there is no need to grind out existing striping.
Left Turn Access at signalized intersections
● Left turn access for northbound and southbound Narbonne Avenue will be enhanced because dedicated left turn lanes will be installed at the signalized intersections of 250th Street and 255th Street. This will enhance visibility for left turning motorists as well as reduce left-turn collision potential.
Conclusions
Recognizing there are factors in addition to LOS that have bearing upon the suitability of roadway reconfiguration on Narbonne Avenue, it is recommended the City consider implementing these striping changes by weighing the potential benefits of facilitating multimodal transportation which supports the City of Lomita’s recently adopted Complete Streets policy.
June 8, 2023 Job No. CLOM0000-0122
MEMORANDUM
To: Suzanne Moubayed, MS, EIT
David Evans and Associates, Inc.
From: James M. Daisa, TE
RE: PRELIMINARY TRAFFIC OPERATIONS ASSESMENT OF NARBONNE / PACIFIC COAST HIGHWAY
INTERSECTION WITH PROPOSED IMPROVEMENTS
This memorandum summarizes a preliminary operations assessment of the intersection of Narbonne Avenue and Pacific Coast Highway in the City of Lomita with implementation of proposed lane reconfigurations.
Proposed Changes to Narbonne Avenue
Narbonne Avenue currently is a four-lane undivided street except at major signalized intersections where a left turn bay is provided. The proposed configuration—a “road diet”—of Narbonne Avenue is to provide one lane in each direction and a continuous center turn lane which transitions into left turn bays at select intersections to provide width to add Class II bicycle lanes in each direction. On-street parking remains as currently configured.
Intersection Capacity Analysis Methodology
With limited traffic volume data, a capacity analysis was performed to identify one of three possible operational conditions with implementation of the proposed road diet: intersection operates below capacity, intersection operates near capacity, intersection operates over capacity. The city’s level of service standard is LOS D.
Available traffic data was limited. The city provided an Engineering & Traffic Survey for establishing speed limits on Narbonne Avenue prepared in 2021 which included daily traffic counts divided into hourly volumes by direction. Bi-directional volumes on Narbonne Avenue for the PM peak hour were available north and south of the Pacific Coast Highway. Peak hour volumes for Pacific Coast Highway were derived from Caltrans’ Traffic Census Program bi-directional peak hour volume data for the year 2021. Caltrans count data was limited to Pacific Coast Highway at Route 231 and at Crenshaw Boulevard.
Intersection turn movements at Narbonne Avenue and Pacific Coast Highway were estimated based on an assumed percentage of directional traffic volumes turning left and right at the approaches of the intersection. The percentages were adjusted so that the departure volumes matched the contributing approach turning volumes as close as possible. The resulting intersection turning movements are rough approximations, but conservative.
Results of Analysis
Based on the assumptions described above, the PM peak hour capacity analysis results in an overall LOS C (see Attachment D) with the northbound and southbound approaches of Narbonne Avenue operating at a LOS D. This finding falls under the operational condition of “intersection operates below capacity”. \ Attachments:
Attachment A – Peak Hour Traffic Data for Narbonne Avenue Attachment B - Excerpt from Caltrans Peak Hour Volume Data (Year 2021) Attachment C - Derivation of Turning Movements from Directional Link Volumes Attachment D - PM Peak Hour Capacity Analysis of PCH and Narbonne Ave Attachment 2
2021
NARBONNE AVENUE
(Between Lomita Boulevard and the
Rolling Hills Estates City Boundary south of Pacific Coast Highway) Engineering and Traffic Survey (E&TS)
Prepared by: Irena Guilmette, T.E. #2259
City of Lomita Traffic Advisor
Los Angeles County Public Works
September 2021
ATTACHMENT A
PEAK HOUR TRAFFIC DATA FOR NARBONNE AVENUE
NARBONNE AVENUE
TRAFFIC VOLUMES
Source: Caltrans Traffic Census Program, Peak Hour Volume Data (Year 2021) https://dot.ca.gov/programs/traffic-operations/census ATTACHMENT B EXCERPT FROM CALTRANS PEAK HOUR VOLUME DATA (YEAR 2021)
ATTACHMENT C
DERIVATION OF TURNING MOVEMENTS FROM DIRECTIONAL LINK VOLUMES HCM 6th Signalized Intersection Summary Synchro 11 Report 2: Pacific Coast Highway (HWY 1) & Narbone Ave 06/05/2023 Baseline
Movement EBL EBT EBR WBL WBT WBR NBL NBT NBR SBL SBT SBR Lane Configurations
Traffic Volume (veh/h) 127 1431 32 36 1104 60 223 159 255 184 41 184 Future Volume (veh/h) 127 1431 32 36 1104 60 223 159 255 184 41 184 Initial Q (Qb), veh 0 0 0 0 0 0 0 0 0 0 0 0
Ped-Bike Adj(A_pbT) 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Parking Bus, Adj 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Work Zone On Approach No No No No
Adj Sat Flow, veh/h/ln 1870 1870 1870 1870 1870 1870 1870 1870 1870 1870 1870 1870 Adj Flow Rate, veh/h 138 1555 35 39 1200 65 242 173 277 200 45 200 Peak Hour Factor 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 Percent Heavy Veh, % 2 2 2 2 2 2 2 2 2 2 2 2
Cap, veh/h 173 2224 50 52 1808 98 286 376 319 242 330 280 Arrive On Green 0.10 0.43 0.43 0.03 0.36 0.36 0.16 0.20 0.20 0.14 0.18 0.18 Sat Flow, veh/h 1781 5138 116 1781 4958 268 1781 1870 1585 1781 1870 1585 Grp Volume(v), veh/h 138 1030 560 39 824 441 242 173 277 200 45 200 Grp Sat Flow(s),veh/h/ln 1781 1702 1850 1781 1702 1822 1781 1870 1585 1781 1870 1585 Q Serve(g_s), s 6.0 19.6 19.6 1.7 16.1 16.1 10.5 6.5 13.5 8.7 1.6 9.5 Cycle Q Clear(g_c), s 6.0 19.6 19.6 1.7 16.1 16.1 10.5 6.5 13.5 8.7 1.6 9.5 Prop In Lane 1.00 0.06 1.00 0.15 1.00 1.00 1.00 1.00
Lane Grp Cap(c), veh/h 173 1473 801 52 1241 664 286 376 319 242 330 280 V/C Ratio(X) 0.80 0.70 0.70 0.75 0.66 0.66 0.85 0.46 0.87 0.83 0.14 0.72 Avail Cap(c_a), veh/h 246 1473 801 134 1241 664 403 423 359 358 376 319 HCM Platoon Ratio 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Upstream Filter(I) 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 Uniform Delay (d), s/veh 35.1 18.3 18.3 38.3 21.2 21.2 32.4 28.0 30.8 33.4 27.6 30.9 Incr Delay (d2), s/veh 11.3 2.8 5.0 19.6 2.8 5.2 11.1 0.9 18.4 9.7 0.2 6.4 Initial Q Delay(d3),s/veh 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 %ile BackOfQ(50%),veh/ln 3.1 7.7 8.9 1.0 6.5 7.5 5.3 2.9 6.6 4.3 0.7 4.0 Unsig. Movement Delay, s/veh
LnGrp Delay(d),s/veh 46.4 21.1 23.4 57.9 24.0 26.4 43.6 28.8 49.2 43.1 27.8 37.3 LnGrp LOS D C C E C C D C D D C D
Approach Vol, veh/h 1728 1304 692 445
Approach Delay, s/veh 23.9 25.8 42.1 38.9
Approach LOS C C D D
Timer - Assigned Phs 1 2 3 4 5 6 7 8
Phs Duration (G+Y+Rc), s 6.3 38.4 16.8 18.0 11.7 33.0 14.8 20.0 Change Period (Y+Rc), s 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 Max Green Setting (Gmax), s 6.0 34.0 18.0 16.0 11.0 29.0 16.0 18.0 Max Q Clear Time (g_c+I1), s 3.7 21.6 12.5 11.5 8.0 18.1 10.7 15.5 Green Ext Time (p_c), s 0.0 8.2 0.3 0.4 0.1 6.1 0.2 0.5 Intersection Summary
HCM 6th Ctrl Delay 29.1
HCM 6th LOS C
ATTACHMENT D
PM PEAK HOUR CAPACITY ANALYSIS OF PCH AND NARBONNE AVE