CITY COUNCIL STAFF REPORT

Transcription

1 CTY COUNCL STAFF REPORT TO: Honorable Mayor and City Council DATE: November 20, 2017 FROM: PREPARED BY: SUBJECT: Matthew Bronson, City Manager Greg Ray, Public Works Director/City Engineer South 16 th Street and Farroll Road Re-Striping RECOMMENDATON Receive information on re-striping near the intersection of South 16 th Street and Farroll Road and approve the design to shift the centerline to the south and relocate on-street parking from the south side to the north side of Farroll Road in order to achieve adequate corner sight distance. BACKGROUND As part of the street repair update on August 7, 2017, staff presented a report from Omni-Means for the Farroll Road and South 16 th Street ntersection Safety mprovements (see Attachment 1). While Council has been made aware of the recommendations from the report, staff would like to provide further information to the Council and receive formal approval of the re-striping design prior to implementation of this re-striping. The City had received multiple complaints regarding the sight distance at the aforementioned intersection. Subsequently, the City hired Omni-Means, a traffic engineering consultant, to study and evaluate several possible improvements intended to address safety concerns at the subject intersection. Staff requested the consultant evaluate intersection sight distance, installation of a crosswalk crossing Farroll Road and installation of a dedicated left-turn lane for eastbound traffic on Farroll Road. The Omni-Means study found that the corner sight distance at this intersection is inadequate for the vehicles traveling southbound on South 16 th Street and attempting to enter or cross Farroll Road. Corner sight distance is the distance needed to provide adequate time for the driver on the crossroad to cross or enter the main road while the approaching vehicle travels at the posted speed of the main road. Omni-Means recommends restriping on Farroll Road to improve the corner sight distance and to achieve the required sight distance according to the Caltrans Highway Design Manual (2016). Restriping would include moving the travel lanes by shifting the center line 8 feet to the south and eliminating on-street parking on the south side of Farroll Road (see Figure 6 of Attachment 1). Staff has observed that this parking area is seldom used. Pending Council approval, this re-striping would be carried out by the end of the year. FSCAL MPACT The cost to restripe a short section of Farroll Road is estimated to be less than $1,500 and there is sufficient funding within the Public Works maintenance budget. Agenda tem No. 7

2 Staff Report: South 16 th Street and Farroll Road Re-Striping Page 2 November 20, 2017 ALTERNATVES The City Council has the following alternatives to consider: 1. Receive information on re-striping near the intersection of S.16th Street and Farroll Road and approve the design to shift the centerline to the south and relocate on-street parking from the south side to the north side of Farroll Road in order to achieve adequate corner sight distance; or 2. Provide alternative direction to staff. PUBLC NOTFCATON The agenda was posted in accordance with the Brown Act. A copy of this staff report and the meeting agenda were sent to interested stakeholders. ATTACHMENTS 1. Omni-Means Memorandum: Farroll Road and South 16 th Street ntersection Study

3 Attachment 61 Technical Memorandum To: City of Grover Beach Date: June 15, 2017 Attn: Greg Ray, P.E. Public Works Director Project: South 16th Street/Farroll Road From: Nate Stong, P.E. Re: Sight Distance, Marked Crosswalk, and Left-Turn Lane Evaluation Job No.: CC: File No.: C2218MEM003.DOCX Summary This memorandum summarizes an evaluation of the intersection of Farroll Road and South 16th Street in the City of Grover Beach. The elements of the intersection analyzed in this study include intersection sight distance, warrants for installation of a marked crosswalk across Farroll Road, and warrants for installation of an exclusive left turn lane eastbound on Farroll Road approaching S. 16th Street. The conclusions of the analysis are summarized below: Corner Sight Distance: Corner sight distance is adequate for all movements except for the southbound S. 16th Street approach looking east along Farroll Road (see Figure 1). The existing corner sight distance for this view is 287 feet, which is below the minimum of 385 feet per the Caltrans Highway Design Manual (HDM) for a 35 mph roadway. Removal of a small tree would provide an additional 32 feet of sight distance, however the resulting 319 feet would remain below minimums. Options for achieving minimum sight distance include relocating a portion of the existing subdivision masonry wall near the northeast corner of the study intersection, or restriping Farroll Road east of S. 16th Street to shift centerline to the south approximately 8 feet. This could be accomplished by relocating the existing on-street parking along the south side to the north side. Tree and masonry wall within sight line Figure 1: Corner Sight Distance Southbound S. 16th St. Looking East along Farroll Road 669 Pacific Street l Suite A l San Luis Obispo, CA l p l omnimeans.com Napa l Redding l Roseville l San Luis Obispo l Visalia l Walnut Creek

4 May 4, 2017 Stopping Sight Distance: Stopping sight distances along Farroll Road at the study intersection are sufficient and exceed minimum distances required per the Caltrans HDM. Marked Crosswalk: The study intersection is a candidate location for the installation of a marked crosswalk across Farroll Avenue, however due to the low volume of pedestrians observed crossing it is not recommended to make the installation a priority. Exclusive Eastbound Left-Turn Lane: An exclusive left turn lane exists in the westbound direction to southbound S. 16th Street. nstalling a complementary left turn lane on eastbound Farroll Road to northbound S. 16th Street is an option although warrants are not currently met. Background n 2013 a new segment of S. 16th Street was constructed which closed a gap in the street network between Huntington Avenue and Farroll Road, connecting to Farroll Road opposite the existing South 16th Street and converting what was prior a "T" intersection to a four-legged intersection. See Figure 2. Figure 2: Location Map 2

5 May 4, 2017 The study intersection is two-way-stop-controlled, with the minor road (S. 16th Street) stopcontrolled. Farroll Road is a two-lane roadway classified as a collector in the City of Grover Beach General Plan Circulation Element, and S. 16th Street is classified as a local street. The posted speed limit on Farroll Road is 35 mph, with Class bike lanes on each side. Data Collection Existing AM and PM peak hour traffic volume counts for the study intersection were collected by Omni-Means in February Bicycle and pedestrian peak hour volumes were also collected. A roadway segment count on Farroll Road, east of 16th Street was also taken to gather daily roadway volumes. Figure 3 shows a summary of these volumes and existing lane geometrics. The percentage of heavy vehicles at the intersection of Farroll Road and 16th Street is 3.4% and 1.7% for the AM and PM peak hours, respectively. 3

6 LANE GEOM ETRCS AND NTERSECTON CONTROLS VEHCULAR PEAK HOU R VOLUMES BKE PEAK HOUR VO LUME S dols q t STOP 16 TH STREET,,., 7 (8) <XJ J 1 00l +-158(1 67)...j..,---9(30) 7 (19)- -+i i 126(255)--+ ll 12(29)-.. -;::- 'Ln,,., >c_ 0(2) OJ Ol +-- 0( 1)...j..,--- 0( 1) 0 c 1 l- 1 i 0(1)--+ o(o)-., LE GEN D: xx - (xx) - AM PE AK HOUR TRA FFC VOLUMES PM PEAK HOU R TRAFFC VOLUM ES 18,000 AVER AGE DALY TRAFF C (ADT), _ MEN TONE A Vll /\ ' PEDES TRAN PEAK HOUR VOLUM ES ASH ST..., 1 CJ.)l h "' h FARROLL AVE ),j HGHLAND WAY r-- 1- h "' h "' f < - - '<l ;1 i:t; l;s- - rn - - THE PKE, y l J \ -1 Farrall Rd / 16th St ntersection Evalu ation Figure 3 Existin g Lone Geometrics and Control \ L_J_ /J/ : 4J P D: \ PRJ\221B\T221B\ 1221 BTG002.DWG

7 ntersection Sight Distance May 4, 2017 Omni-Means staff measured the available sight distances at the study intersection in April The following section presents the analysis of Stopping Sight Distance and Corner Sight Distance using the Caltrans HDM as a guide. Stopping Sight Distance Stopping sight distance is the distance required by the driver, traveling at a given speed, to bring the vehicle or bicycle to a stop after an object 1/2-foot high or larger on the road becomes visible. 1 Source: Caltrans Highway Design Manual, 2016 To evaluate the stopping sight distance, Chapter 200 of the Caltrans HDM was applied. As shown in the table above, a 35 mile per hour speed limit corresponds to a required minimum 250 foot stopping sight distance. Figure 4 illustrates the available and the required stopping sight distance for Farroll Road at the study intersection. 1 Highway Design Manual Section

8 STOPPNG SGHT DSTANCE Scale: 1"=80' Figure No. 4 S. 16th St/Farroll Rd Grover Beach, CA omni means.. EN$1NEERN$ SOLUTONS May4, EX002.dwg

9 May 4, 2017 Corner Sight Distance Corner sight distance is the distance needed to provide adequate time (7.5 seconds) for the driver on the crossroad to cross or enter the main road while the approaching vehicle travels at the posted speed of the main road. 2 Source: Caltrans Highway Design Manual, 2016 To evaluate the corner sight distance, Chapter 400 of the HDM was applied. As shown in the table above, a 35 mile per hour speed limit corresponds to 385 foot minimum corner sight distance. Figure 5 illustrates the available and the minimum corner sight distance required for the study intersection. As shown in Table 405.1A and Figure 5, the available corner sight distance at S. 16th Street to the eastbound vehicles on Farroll Road is adequate for the posted speed of 35 mph. However, there is insufficient corner sight distance to the westbound vehicles on Farroll Road from a vehicle southbound on S. 16th Street attempting to enter or cross Farroll Road. The corner sight distance to westbound traffic is 287 feet. An additional 32 feet could be obtained by removing/relocating the tree illustrated in Figure 4. However the resulting 319 feet of sight distance would remain below the minimum required. A masonry wall near the northeast corner of the study intersection remains in the required sight line (refer to Figure 1). Removal of the masonry wall obstruction is one option, however recognizing the right of way requirements and impact to new homes in the subdivision other options for improving sight lines are explored here. One option considered would be to shift the through lanes of Farroll Road to the south approximately 8 feet, potentially achieved by relocating the existing on-street parking along the south side of Farroll Road to the north side. This option is presented in Figure 6. Other options which could be explored include reducing the speed on Farroll Road to 25 mph through use of speed humps or other physical traffic calming measures, or the installation of an all-way stop at S. 16th Street. 2 Highway Design Manual Section 405.1(2)(a) 7

10 CORNER SGHT DSTANCE S. 16th St/Farrall Rd Grover Beach, CA omni means - ENGNEERNG SOLUTONS May 4, EX002.dwg

11 CORNER SGHT DSTANCE (CSD) WTH RESTRPNG / Scale: 1"=80' Figure No. 6 S. 16th St/Farroll Rd Grover Beach, CA omni means.. EN$1NEERN$ SOLUTONS May4, EX002.dwg

12 Marked Crosswalk May 4, 2017 Consideration of the installation of a marked crosswalk at an uncontrolled intersection (i.e. no stop signs, signal, or other intersection control for the facility to be crossed) should take into account the volume of vehicular and pedestrian traffic, the speed of the facility, the number of lanes to be crossed, and other factors including sight distance, lighting, etc. Using the guidance provided in the 2005 FHWA document "Safety Effects of Marked Versus Unmarked Crosswalks at Uncontrolled Locations" the installation of a marked crosswalk crossing Farroll Road is evaluated in this section. The existing average daily traffic (ADT) on Farroll Road, east of 16th Street is 4,600 vehicles per day (vpd) and the posted speed for both approaches is 35 mph. As can be seen in Table 1, for a two-lane undivided roadway type with ADT of less than 9,000 vpd, the site location is a candidate for the installation of a marked crosswalk, either on the west side crossing two lanes or on the east side crossing 3 lanes (including center left turn lane). However, the guidance states that "it is recommended minimum of 20 pedestrian crossings per peak hour (or 15 or more elderly and/or child pedestrians) exist at a location before placing a high priority on the installation of a marked crosswalk alone". As presented on Figure 3 earlier in this report, there were 2 pedestrians counted crossing Farroll Road at S. 16th Street in the AM peak hour and 2 in the PM. Based on the low pedestrian volumes this location is not considered a high priority for the installation of a marked crosswalk at this time. Should a marked crosswalk be considered, the east side would appear to be the better location despite crossing 3 lanes as it provides the best visibility of pedestrians waiting to cross and would also locate the crossing adjacent to Hero Community Park. The sight distance issue is most critical for the pedestrian crossing north to south, and a pedestrian on the northeast corner is more visible from a vehicle travelling westbound approaching the intersection. A pedestrian crossing from the northwest corner would be less visible due to the masonry wall located near the northeast corner. 10

13 May 4, 2017 Source: FHWA Safety Effects of Marked Versus Unmarked Crosswalks at Uncontrolled Locations,

14 May 4, 2017 Eastbound Left-Turn Lane Evaluation Accommodating left turns at uncontrolled intersections has been investigated and studied over the last 50 years. These studies have helped develop guidelines on when an exclusive left-turn lane is warranted for given situations. Consideration for installing a left-turn lane at an uncontrolled intersection should take into account roadway classification, number of lanes, prevailing speeds, traffic control, traffic operations, volumes, roadway alignment alignments and safety. The eastbound approach of Farroll Road to S. 16th Street was evaluated for a left-turn lane using the guidance provided in the NCHRP document "Development of Left-Turn Lane Warrants for Unsignalized ntersections." The following two methods were used to determine if a left-turn lane is warranted for this approach: Oppenlander & Bianchi Method and the Bonneson & Fontaine Method. Figure 7 shows the movements that are used to determine the need for a left-turn lane in several guidelines/warrant methods. Table 2 shows a summary of these movements both peak periods. Source: NCHRP Development of Left-Turn Lane Warrants for Unsignalized ntersections, 2010 Figure 6 - Volumes for use in Left-Turn Warrant Methods Table 2 - Farroll Road Volumes and Left-Turn Percentages Peak Period AM PM Advancing Volume (V A ) (vph) Left Turning Volume (V L ) (vph) 7 19 Straight Through Volume (V S ) (vph) Opposing Volume (V O ) (vph) Left Turn Percentage (P L ) (%)

15 May 4, 2017 As shown in Figure 7, an exclusive left-turn lane is not warranted based on advancing volumes, opposing volumes, and left-turn percentages in both AM and PM peak hours. For an exclusive left-turn lane to be warranted, the opposing and advancing volumes would need to be high enough to surpass it's corresponding left-turn percentage threshold. 800 Speed Limit = 35 mph 600 %Left Turn 4.0 Advancing Volume (vph) % Legend AM % PM Opposing Volume (vph) Figure 7 - Oppenlander and Bianchi Method 13

16 May 4, 2017 As shown in Figure 8 and Figure 9, an exclusive left-turn lane is not warranted based on the posted speed, percent of left-turns, advancing volumes, and opposing volumes in both peak periods. Figure 8 - Bonneson & Fontaine Method - AM Peak Figure 9 - Bonneson & Fontaine Method - PM Peak 14

17 May 4, 2017 Conclusion and Recommendations The elements of the intersection analyzed in this study include intersection sight distance, warrants for installation of a marked crosswalk across Farroll Road at S. 16th Street, and warrants for installation of an exclusive left turn lane eastbound on Farroll Road approaching S. 16th Street. The conclusions and recommendations of the analysis are summarized below: Corner Sight Distance: Corner sight distance is adequate for all movements except for the southbound S. 16th Street approach looking east along Farroll Road (see Figure 1). The existing corner sight distance for this view is 287 feet, which is below the minimum of 385 feet per the Caltrans Highway Design Manual for a 35 mph roadway. Removal of a small tree would provide an additional 32 feet of sight distance, however the resulting 319 feet would remain below minimums. Options for achieving minimum sight distance include relocating a portion of the existing subdivision masonry wall near the northeast corner of the study intersection, or restriping Farroll Road east of S. 16th Street to shift centerline to the south approximately 8 feet. This could be accomplished by relocating the on-street parking along the south side to the north side (see Figure 6). Stopping Sight Distance: Stopping sight distances along Farroll Road at the study intersection are sufficient and exceed minimum distances required per the Caltrans HDM. Marked Crosswalk: The study intersection is a candidate location for the installation of a marked crosswalk across Farroll Avenue, however due to the low volume of pedestrians observed crossing it is not recommended to make the installation a priority. Exclusive Eastbound Left-Turn Lane: An exclusive left turn lane exists in the westbound direction to southbound S. 16th Street. nstalling a complementary left turn lane on eastbound Farroll Road to northbound S. 16th Street is an option although warrants are not currently met. 15