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CC - Item 4B - Installation Left Turn Signal Phasing Del Mar Ave at Gravesi TO: HONORABLE MAYOR AND MEMBERS ROSEM D CITY COUNCIL i~V FROM: BILL CR E, CITY MANAGER DATE: SEPTEMBER 21, 2005 r- r -I LJ RE: INSTALLATION OF LEFT TURN SIGNAL PHASING ON DEL MAR AVENUE AT GRAVES AVENUE At the request of a councilmember, staff analyzed the intersection of Del Mar Avenue and Graves Avenue for the installation of left turn signal phasing on Del Mar Avenue. There was concern that vehicles, especially those traveling southbound, have difficulty turning left due to the speed of traffic and the vertical curve north of Graves Avenue. A detailed analysis of the intersection can be found in the attached Traffic Commission staff report. In summary, the results of the traffic study were compared to guidelines (warrants) found in the Manual of Uniform Traffic Control Devices (MUTCD) which have been prepared based on nation-wide examinations of a broad cross-section of locations. Two of the guidelines were satisfied, volume and miscellaneous factors, which involved visibility. The subject intersection straddles the boundary between the City of Rosemead and unincorporated Los Angeles County. Therefore, jurisdiction over the traffic signal is shared, with the County the lead agency for maintenance activities. For this reason, it will be necessary to obtain the County's approval and concurrence of the above facts before the necessary traffic signal modifications can be designed and the left turn phasing installed. If the City Council concurs with the Traffic Commission's recommendation, approve the installation of a left turn traffic signal phasing in the north and southbound directions Del Mar Avenue at Graves Avenue, and authorize staff to contact Los Angeles County Department of Public Works to obtain their approval. .~~r.t;t P, SEP 2 7 2005 rrEfa Nto. ~e:~ • • Staff Report Rosemead Traffic Commission TO: HONORABLE CHAIRMAN AND MEMBERS ROSEMEAD TRAFFIC COMMISSSION FROM: JOANNE ITAGAKI, TRAFFIC ENGINEERING DEPUTY DATE: August 23, 2005 RE: Request for Left Turn Signal Phasing on Del Mar Avenue at Graves Avenue REQUEST Councilmember Nunez has requested staff analyze the intersection of Del Mar Avenue and Graves Avenue for the installation of left turn signal phasing on Del Mar Avenue. Councilmember Nunez is concerned that vehicles, especially southbound, have difficulty turning left due to the speed of traffic and the vertical curve north of Graves Avenue. CONDITIONS Del Mar Avenue is a 64-foot wide north-south roadway with two lanes of traffic in each direction. A double yellow centerline separates opposing lanes of traffic. There are dedicated left turn lanes in both the northbound and southbound directions of Del Mar Avenue at Graves Avenue. The posted speed limit on Del Mar Avenue is 35 mph. Graves Avenue is a 54-foot wide east-west roadway with one lane of traffic in each direction. In the vicinity of Del Mar Avenue, the opposing lanes of traffic are separated by a double yellow centerline. There are dedicated left turn lanes in both the eastbound and westbound directions of Graves Avenue at Del Mar Avenue. The posted speed limit on Graves Avenue is 35 mph. DATA The reported collision history at the intersection of Del Mar Avenue and Graves Avenue was reviewed for the period from January 1, 2000 to May 2005. These collisions will be summarized in Exhibit A, available at the Traffic Commission meeting. There were 8 collisions reported during this period within 250 feet of the intersection. Four of these collisions occurred in 2000. Two collisions occurred in 2002 and two occurred in 2003. There were no reported collisions in 2004 or 2005. City staff is in the process of requesting any additional reported collisions at the subject intersection with the California Highway Patrol (CHP). This request is • September 9, 2005 Traffic Commission Meeting Request for Left Turn Signal Phasing on Del Mar Avenue at Graves Avenue Page 2 of 4 49 being made because Del Mar Avenue and Graves Avenue is on the City boundary with parts of the intersection in the County. It is possible that reported collisions might not be in the City's database. Staff will update the reported collision history at the Traffic Commission meeting. Turning movement counts were taken at the intersection in July. These counts revealed the following: AM Peak 7:45-8:45 PM Peak 5:00-6:00 Northbound Left Turn 167 223 Straight 388 557 Ri ht Turn 34 36 Southbound Left Turn 46 75 Strai ht 496 454 Right Turn 46 53 Eastbound Left Turn 61 59 Straight 136 184 Right Turn 233 216 Westbound Left Turn 34 24 Straight 173 154 Right Turn 61 69 DISCUSSION Field observations of the intersection of Del Mar Avenue and Graves Avenue were made at several different times of the day. Overall, the traffic volumes and traffic flow at the intersection are very light with minimal delay and congestion experienced. In reviewing the left turn movements on Del Mar Avenue, the southbound left turn direction was found to have some visibility constraints during certain times of the day. Like the installation of a traffic signal, the Manual of Uniform Traffic Control Devices (MUTCD) provides guidelines for the installation of left turn phasing. These guidelines are as follows: 1. Accidents - Five or more left turn accidents for a particular left turn movement during a recent 12-month period. • 0 September 1, 2005 Traffic Commission Meeting Request for Left Turn Signal Phasing on Del Mar Avenue at Graves Avenue Page 3 of 4 2. Delay - Left-turn delay of one or more vehicles, which were waiting at the beginning of the green interval and are still remaining in the left turn lane after at least 80% of the total number of cycles for one hour. 3. Volume - At new intersections where only estimated volumes are available, the following criteria may be used. For pre-timed signal or a background- cycle-controlled actuated signal, a left turn volume of more than two vehicles per approach per cycle for a peak hour; or for a traffic-actuated signal, 50 or more left turning vehicles per hour in one direction with the product of the turning and conflicting through traffic during the peak hour of 100,000 or more. 4. Miscellaneous. Other factors that might be considered include but are not limited to: impaired sight distance due to horizontal or vertical curvature, or where there are a large percentage of buses and trucks. For the intersection of Del Mar Avenue and Graves Avenue, the guidelines are compared as follows: 1. Accidents - The highest number of reported accidents occurred in 2000 with 4 reported collisions. Three of these collisions would be considered left turn accidents. However, the year 2000 would not be considered a "recent 12- month period". The most recent reported accident occurred in 2003. Therefore, this guideline is not satisfied. 2. Delay - Based on the field observations of the intersection, it is estimated that less than 80% of the signal cycles experience some delay to the left turning vehicles. Therefore, this guideline is not satisfied. 3. Volume - This intersection is not a new intersection but the relationship to the product can be made as a comparison. The northbound left turn volume product in the AM is 82,832 and in the PM is 101,242. For the southbound left turn volume produce, the AM is 17,848 and in the PM is 41,775. Therefore, the volume product is satisfied in the northbound direction during the PM peak hour. 4. Miscellaneous. The visibility of northbound traffic while in the southbound left turn lane is usually clear with the horizontal and vertical curves on Del Mar Avenue south of Graves Avenue. On average, a southbound left turning vehicle can first see a northbound vehicle approximately 12 seconds before that vehicle reaches the intersection. This is an adequate amount of time for motorists to determine when an adequate gap in traffic occurs. However, when there is a long line of northbound left turning vehicles in the left turn lane, the vehicles block the visibility of northbound through traffic for southbound left turn lanes. The 12 second time visibility time is reduced significantly to less than 5 seconds. i • September 1, 2005 Traffic Commission Meeting Request for Left Turn Signal Phasing on Del Mar Avenue at Graves Avenue Page 4 of 4 Based on the reduced visibility discussed above, it is recommended that left turn phasing be installed in the northbound and southbound directions of Del Mar Avenue at Graves Avenue. 1259 0 0 47!40 ?.002/002 A r of _ N w ~ p 7 ~ 7 O O O M w ,r r R a ~ O ~y r ~ r 4 N ~ =1 E ~ a ~ a N c c U cx O O 'o m M rAm Jm1 m m g g g d a ~ d a`V O w U.n ac 0 V) 0 a V) - . . O N ` z s in w' t°n Z - o l0 C U • Q Oi W C~ a act F- C F- _c ~ T m yci ~ 'CCE sE rn ~c m y 0 ~a t~~ ti- 1.2 CLM U~ w w drn C j = ' r V t= US co ui V c ~1 v eke r ¢ o g o a o ~ O >9ar m m gm m mm ~zm~ > ~5 o> > o o> o> O> O> O> ~n O _ c so m c m CD 4 w p N w U V w ` w '7 (A V w N c~ V C a V m cn m m m yi T ami 0 0 5 m 0 z° to l 5 T N to ti O m C > E q ~ ! N Q :v 1 m C {p N Or1 S N \ 0 CL © r o ~ 0 v 0 v °a R N n ~ cn o iy ~ n ~ a r- cn ~ cn °C a a a G C A D _ a u C -1u )k. 1.2 i ` • • ROSEMEAD TRAFFIC COMMISSION SEPTEMBER 1, 2005 The regular meeting of the Rosemead Traffic Commission was called to order by Chairman Quintanilla at 7:00 p.m., in the Council Chambers, 8838 East Valley Boulevard, Rosemead. ROLL CALL Present: Chairman Quintanilla, Vice-Chairperson Matsdorf and Commissioner Knapp Absent: None Pledge of Allegiance: Commissioner Matsdorf Invocation: Commissioner Knapp APPROVAL OF MINUTES - Deferred until October 6, 2005 H. ORAL COMMUNICATIONS FROM THE AUDIENCE Speaking before the Commission was: Learul Dalessio 1030 W. Crumbly Street West Covina, California 91790 Ms. Dalessio passed out letters to the Commissioners regarding cars parking in front of the Chamber of Commerce blocking their driveway, and thought perhaps the curb could be painted. Deputy Traffic Engineer Itagaki stated that she will look into it, and bring it forth to the Traffic Commission in the month of October. III. OLD BUSINESS - NONE 0 0 IV. NEW BUSINESS A. _REQUEST FOR LEFT TURN SIGNAL PHASING ON DEL MAR AVENUE AT GRAVES AVENUE Deputy Traffic Engineer Itagaki presented the staff report. Recommendation: Based on the reduced visibility discussed above, it was recommended that left turn phasing be installed in the northbound and southbound directions of Del Mar Avenue at Graves Avenue. Commissioner Knapp recommended that perhaps the County could share the cost of the signal. It was moved by Commissioner Matsdorf, seconded by Commissioner Knapp, and carried unanimously to approve the Traffic Engineer's recommendation. V. STAFF REPORTS - None VI. COMMISSIONER REPORTS Commissioner Matsdorf reminded everyone that school starts up again on Tuesday, September 6th. Chairman Quintanilla asked about the bus stop in front the beauty shop. Assistant City Manager Wagner stated that the City has met with both the owner of the Beauty Shop and the owner of the shopping center, and will be asking MTA to remove the bus stop. VII. ADJOURNMENT There being no further business to come before the Commission, the meeting was adjourned at 7:27 p.m.