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HomeMy WebLinkAbout6.3 PpprtreeShnnnTrffcStdy CITY OF DUBLIN AGENDA STATEMENT City Council Meeting Date: June 9, 1986 SUBJECT: Public Hearing: Traffic Study Intersection of Peppertree Road and Shannon Avenue • EXHIBITS ATTACHED: Report from TJKM RECOMMENDATION: 1) Open Public Hearing and Receive Staff Presentation M 2) Receive Public Testimony ' 3) Question Staff and the Public 4) Close Public Hearing and Deliberate 5) Approve Continued Enforcement of Speed Limit by • Dublin Police Services FINANCIAL STATEMENT: None DESCRIPTION: At its meeting of May 12, 1986, the City Council requested that TJKM review the installation of stop signs on Peppertree Road at the intersection of Shannon Avenue. The following studies were conducted in response to this request: 1) Review of accident history. - 2) 24-hour machine counts. • • 3) Peak hour turning movement counts. 4) Radar speed study. 5) Field investigation. Based on these studies, TJKM indicates that installation of STOP signs on Peppertree Road at the intersection of Shannon Avenue would not solve the problem of speeding on Peppertree Road and that there are no accident nor other intersection motorist problems that would be resolved by the installation of STOP signs. The Staff recommendation is that Dublin Police Services continue issuance of citations to discourage violations. Dublin Police Services records indicate that 45 citations, representing 22.5 hours of traffic enforcement, were issued on Peppertree Road during the • last two months. 4 • • ITEM NO. 6 • COPIES TO: TJKM Dublin Police Services RF. CF.i¥ ED TRANSPORTATION SuL1ANTS PLEASANTON SACRAMENTO FRESNO CONCORD DATE: TO: FROM: SUBJECT: June 4, 1986 Lee Thompson, City Engineer Ty Tekawa, TJKM Traffic Study, Intersection of Peppertree Road and Shannon Avenue At the City Council meeting of May 27, 1986, TJKM presented recommendations for traffic problems along the 8000 block of Peppertree Road. In addition to the recommendations that were presented, the City Council requested that TJKM review the installation of STOP signs on Peppertree Road at its intersection with Shannon Avenue. We have completed the following additional analyses: at Peppertree Road and Shannon Avenue: (1) accident history at and near the intersection; (2) new 24- hour machine counts; (3) p.m. peak hour turning movement counts; (4) radar study, and; (5) field investigation. Accident History There were no reported accidents at the intersection of Shannon Avenue and Peppertree Road for 1984, 1985 and 1986 to date. As stated in our previous report, there were five accidents recorded from 1984 to the present at the north end of Peppertree Road. 2. 24-Hour Machine Counts Machine counts were taken at the westbound approach on Shannon Avenue and the southbound approach on Peppertree Road. Since there were no acceptable "tie-down" points for a .northbound count on Peppertree Road, that count was estimated by examining the peak hour turning count taken on June 2nd, using ten percent as the amount of traffic during the p.m. peak hour. The 24-hour traffic northbound is estimated at 990 vehicles. Southbound count on Peppertree ar Shannon was 663 cars. The westbound approach on Shannon Avenue at Peppertree Road was 1,037 vehicles per day. (Summaries of these counts are attached.) 3. Peak Hour Turning Movement Counts To determine the traffic pattern at the intersection of Peppertree Road and Shannon Avenue, a p.m. peak hour count was taken on June 2, 1986. The counts were taken from 4:00 to 6:00 p.m.. The results, which show the peak 4637 Chabot Drive, Suite 214 / Pleasanton, California 94566 · (415) 463-061~1 Mr. Lee Thompson -2- June 4, 1986 hour, are shown on the attached Figure 1. The figure shows that the heaviest movement at the intersection is the west to the south left turn from Shannon Avenue onto Peppertree and the right turn movement in the opposite direction. 4. Radar Study During the May 27th Council meeting, a citizen stated that the peak speeding problem occurs at about 4:30 p.m.. TJKM conducted another radar speed study on June 2nd that covered that time. Results of that study are also attached. As shown on the summary, the 85th percentile speed southbound on Peppertree is 38 mph and northbound 39 mph. These speeds are similar to the results of our previous survey and are well in excess of the existing 25 mph speed limit. 5. Field Investigation Both Peppertree Road and Shannon Avenue are 44 feet wide. Peppertree Road is striped with a double yellow centerline. Shannon Avenue has a double yellow centerline approximately 100 feet long from Peppertree Road. The intersection is equipped with one STOP sign, requiring westbound Shannon Avenue traffic to stop prior to entering Peppertree Road. There are no STOP signs along Peppertree Road except at Vomac Road to the north and Silvergate Road to the south. All cross streets between Vomac and Silvergate are controlled with STOP signs. Shannon Avenue forms a "T" intersection at Peppertree Road. There is a horizontal curve and a steep downgrade along Peppertree Road at Vomac Road. The grade levels off as it approaches Shannon Avenue and is almost level across the intersection. This section of roadway is straight. There is a curve to the left for traffic headed southbound beyond Shannon Avenue. The apex of this curve is near Juarez Lane which forms a "T" intersection on the opposite side of Peppertree just south of Shannon Avenue. Sight distance along Peppertree Road for traffic at the STOP sign at Shannon Avenue is somewhat obscured by parked cars, a large bush on the southeast corner and the aforementioned curve south of the intersection. However; it appears that the removal of parking or other mitigation is not necessary if reasonable care is exercised. There have been no reported accidents at the intersection for at least the last 30 months. Comments and Recommendations Although Shannon Avenue and Peppertree Road is a three-legged intersection, conditions at the intersection were compared with warrants for a four-way stop installation. Comparisons of conditions with the STOP sign warrants indicate that the warrants may be marginally satisfied, but there is neither a demonstrated accident problem nor any other intersection motorist probelm that would be resolved by the installation of STOP signs. The complaint expressed at the Council meeting was speeding along the 8000 block of Peppertree Road. The radar studies show that the 85th percentile speed is about 38-39 mph, which means that 85 percent of the surveyed vehicles were traveling at 38-39 mph or less. Mr. Lee Thompson -3- June 4, 1986 In conversations with the Police Chief, we have learned that the 8000 block of Peppertree Road receives one of the highest levels of enforcement activity in the City. When police are present, compliance with the speed limit is much better, but speeds increase when the police leave. Numerous studies have shown that the installation of STOP signs do not reduce speeding. The attached July 5, 1983 memo describes a speed study done on Davona Drive after the installation of STOP signs at two intersections. This study showed that there was no reduction of speed as a result of the STOP sign installations. A study performed by TJKM in the City of Palo Alto where there were a number of three-way stops at "T" intersections showed a high percentage of non-compliance to the STOP signs. On the side of the street that has no cross street (the top of the "T"), the percentage of cars that stop is lower than cars driving on the stem of the "T". The Palo Alto study showed that only 7.17 percent of all vehicles stopped when there were no other cars present and that 29.89 percent stopped when there were other cars at the intersections studied. The peak hour turning movement counts show that the predominant movement of traffic at Peppertree Road to and from Shannon Avenue is to the south of Shannon. An installation of a STOP sign at this location would have the least effect on the majority of the traffic. Most of the traffic turns away from the 8000 block of Peppertree Road during the peak hour. (The hour when most speeding is observed.) Since previous studies show the STOP signs do not reduce speeds and since the installation of unwarranted STOP signs would likely result in the majority of motorists ignoring the STOP signs, it is our recommendation that STOP signs on Peppertree not be installed. TJKM recommends that the Dublin Police Department continue to issue citations to speeders along Peppertree Road to discourage continued violations. TT/psw Attachments 157-001 TJKM MACHINE COUNT SUHMARY Agency_- DUBLIN Nachine ~ 5 LocatiOn: PEPPERTREE RD. NORTH OF SHANNON AVE. Type of count: 1 - WAY Direction: SOUTHBOUND DAY ~ THU. I FRI. I DATE ~ 5/29/86 I 5/20/86 ~ , 12- 1 aml - I 2 I - , 1-2am I - I 1 I 2-3am , 3-4am I 4-Sam ~ I 2 I 5- 6 am I I 10 ' 6- 7 am ] - I 28 I - 7- 8 am ] - ] 63 I - 8- 9 am ~ - J 69 I - 9-10 am I - ~ 41 I - 10-11 am I - I 19 ] - 11-12 am I - I 31 ] - 12- 1 pm I - 18 ~ - 1- 2 pm - 25 ~ - 2-3 pm 3- 4 pm 47 47 , 4- 5 pm I 71 ~ I 5- 6 pm ~ 47 I - I 6- 7 pm 7- 8 pm 8- 9pm 9-10 pm 10-i1 pm J 6 J - J AM PEAK J 11-12 0 .0 8- 9 69 .0 J 11-!2 0 .0 TOTAL PM PEAK j 4- 5 258 71 .0 3- 4 405 47 .0 ,J 11-12 O0 .0 I' A D T ..... 66.3 TJKM MACHINE COUNT SUMMARY Agency: DUBLIN Machine ~ 4 Location: SHANNON AVE. EAST OF PEPPERTREE RD. Type of count: 1 - WAY Direction: WESTBOUND DAY , THU. , FRI. DATE I 5/29/86 I 5/30/86 -iS:-i-;;,,-? ............. : ....... i ........... s 3- 4 am , - 4- $ am , - , 6-.7 am I - J 22 J - 7- 8 am I - J 62 J - _1 8- 9 am J - J 72 , 9-10 am ] - I 37 I' - ' 46 ~ - 10-11 am I - , , ' 47 ' - 11-12 am -i~:-i-62-? ............. : ....: 51 : - 1- 2 pm I - ~ 51 I - 2- 3 pm ~ - , 3- 4 pm ] - J 88 , 4- 5 pm J 81 J I I 6- 7 pm I 72 7- 8 pm I 55 8- 9 pm I 57 9-10 pm J 43 J - ,~ 10-11 pm J 29 ~ - J 11-12 pm J 13 J - J PM PEAK j 5- 6 124 .0 i 3- .4 88 .0 j 11-12 0 .0 ' TOTAL ~ 474 , 563 , 0 I I A O T ..... 1037 SPOT SPEED STUDY ANALYSIS FOR THE CITY OF' DUBLIN LOCATION PEPPERTREE RD. BETWEEN DIRECTION DAY OF THE WEEK DATE TIME OF THE DAY POSTED SPEED LIMIT VEHICLES OBSERVED SOUTHBOUND MONDAY 6-2-86 4:00-6:00 25 69 W. VOMAC RD.& SHANNON AVE. DEVELOPMENT RESIDENTIAL 50th PERCENTILE SPEED 31 85th PERCENTILE SPEED 38 10 MPH PACE SPEED 25 TO 34 PERCENT IN PACE. SPEED 69 RANGE OF SPEEDS 19 TO 46 SKEWNESS INDEX 1.20 CUMULATIVE Sg'EED CURVE SPEED NUM- PERCNT. (MPH) BER OF TOT. 19 1 1. 45 20 0 0. 00 ~':'1 0 0. 00 =~ 1 1. 45 ~c'~ 0 0. 00 24 1 1. 45 25 4 5. 80 2~ 3 4. 35 27 4 5. 80 28 ~4 5. 80 29 4 5. 80 30 10 14. 49 31 4 5. 80 ~':' 6 8 70 34 3 4. 35 35 ~';' 4. 35 36 2 ,_.'--' 90 37 ':,' 2. 90 38 ! i. 45 39 5 7. 25 40 1 1. 45 41 1 1.45 42 1 1. 45 43 1 1. 45 44 0 0. 00 45 0 0. 00 460 1 1. 45 47 ~Z~ 0. 00 48 0 0. 00 49 0 0. 00 50 0 0. 00 51 0 0. 00 ~ 0 0. 00 5S 0 0. 00 54 0 0. 00 56 0 0. 00 57 0 0. 00 58 ~ZI 0. 0 0 CUMUL. PRCN'F. 100% 1.45 1. 45 i. 45 ':'. 90 90% 4.35 14.49 80% 20. 29 26. 09 31.88 46. 38 70;: 52. 17 60. 87 69.57 73.91 60% 78.26 B4.06 92. 75 94. 20 95. 65 97. 10 40% 98. ~= 98. 55 98. 55 100. 0~]. 30% 100. 00 100. 00 100. 00 100. 00 20% 100. 00 100. 00 100. 00 100. 00 10% 100. 00 100. 00 100. 00 100. 00 0% 0 10 20 30 40 SPEED 50 (MPH) 60 70 SPOT ~PEED STUDY ANALYSIS FOR THE CITY OF DUBLIN LOCATION DIRECTION DAY OF THE WEEK DATE TIME OF THE DAY POSTED SPEED LIMIT VEHICLES OBSERVED P E.C'F'E RT REE NORTHBOUND MONDAY 6-2-86 4:~0-6:00 PM RD. BETWEEN W. VOMAC RD. & ~S~NNON AVE. DEVELOPMENT RESIDENTIAL 50th PERCENTILE SPEED 32 85th PERCENTILE SPEED 39 10 MPH PACE SPEED 27 TO 36 PERCENT IN PACE SPEED 67 RANGE OF SPEEDS ~3'='- TO ~ SKEWNESS INDEX 1.18 CUMULATIVE SPEED CURVE SPEED NUM- PERCNT. (Mt'H) BER OF TOT. 23 1 1.37 24 ,3 4. 11 25 2 ~'='. 74 26 ;--' 2. 74 27 5 6. 85 28 ':' ,_.. ,- ':'. 74 29 7 9. 59 30 '-' ,- ,.....':'. 74 3'i- 10 1'?~. 70 ~,- 4 5.48 33 4 5. 48 34 4 5. 48 35 7 9. 59 36 4 5. 48 ' 37 2 c,,. 74 38 3 4. !t 39 ;--' ':-'. 74 40 ':' ,-- '--'. 74 4i i 1.37 42 1 1.37 43 ':.' 2. 74 44 0 0. 45 ':" 2:. 74 46 0 0. 00 47 0 0. 00 48 0 0. 00 49 0 0. 00 50 1 I. 37 5 i 0 0. 00 ~= 0 0. 00 53 0 0. 00 54 0 0. 00 ,~o 0 0. 00 58 0 0. 00 57 0 0. 00 58 0 0. 00 59 0 0. 00 60 0 0. 00 6t 0 O. 00 62 ;ZI 0. 00 CUMUL. PRCNT. 100% 1. 37 5. 48 10. 96 90% 17.8i ;--'0. == 30. i4 '~':' 88 80% 46. 5S 52. 05 57. 53 63. 01 70% 72. 60 78. 08 80. 8~ 84. 93 60% 87. ~7 90. 4i 91. 78 93. 15 ='~r' 95. 89 95. 89 98. 63 98. ~3 40% 98. 63 98. ~3 98. 63 100. 00 30% 100. 00 100. 00 100. 00 t 0~. 00 20% 100. 00 100. 00 100. 00 100. 00 10% 100. 00 100. 00 100. 00 100. 00 0% 0 10 20 30 40 50 SPEED (MPH) 60 79 uJ ~ SHANNON AVE. I-. ~- 19 [.u ~ 53 I DATE OF COUNT JUNE 2, 1986 PEAK HOUR-4:30 TO 5:30 CITY OF DUBLIN PEAK HOUR VOLUMES ?]GURE AT PEPPERTREE RD. & SHANNON AVE. TRANSPORTATION CONSULTANTS , , WARRANTS FOR FOUR-WAY STOP SIGN INSTALLATION Four-way stop sign installation may be considered if any of the following conditions exist, 1. VOL~E (a) Total vehicular volume entering the intersection from ~ll approaches must average 300 per hour for any 8 hours of an average day. (24-hour equival- ent approximately 4000 vehicles.) (b) In addition, the vehicular volume entering the in- tersection from the minor street or streets for the s~me 8 hours must average at least 1/3 of the total volume entering the intersection (100 per hour min.) 2. ACCIDENTS Five or more of types susceptible of correction by stop signs within a 12-month period, with satisfactory ob- servance and enforcement of less restrictive control. 3. VISIBILITY The straight line sight distance on one or more approach- es of the major street for vehicles or pedestrians cross- ing the intersection is less th~n 160 feet. RESIDENTIAL AREA Volume warrants to be reduced to 60% of the values above if ALL of the following conditions are met, (a) Both streets have residential frontage with existing 25 mph speed limits. Neither street is an adopted through street. (c) Neither street exceeds 40 feet of roadway width. (d) No existing stop sign or signal is located on the more heavily traveled street within a distance of 800 feet. (e) (f) Intersection has four legs, with streets extending 800 feet or more away from the intersection on at least three sides. Installation of a four-way stop is comparable with overall traffic circulation needs for the residen-, tiai area. mid-thirties and the area is now undergoing some development. mph limit is recommended for this area. A 35 We made four different radar checks in the residential area. These are summarized on Table 1. Average speeds during the checks ranged from 31 to 34 mph. During each ~ime period, there were observed speeds as high as 44 to 48 miles per hour. Of the 434 motorists clocked, only 21 (less than 5 percent) were travelling at or below the 25 mph speed limit. A basic problem with this section of Amador Valley 8oulevard is that it is both a residential street and an arterial street. It cannot effectively serve both roles, even though it does not seem practical to eliminate either one. The 1983 - 84 budget includes recommendations for detailed studies of this street. This study will include the best use of the existing median area to satisfy the dual roles of the street. Some cities in California are beginning to consider the use of speed humps on streets with on-going speeding problems. Because they constitute an added 'hazard', they have a potential 1 iabilty to the public agency. They are, however, effective in reducing speeds near the installation. On the other hand, they are rarely used on arterial streets such as Amador Valley 8oulevard. We will continue to monitor the progress of the use of such devices in the state. They are not recommended at this time. We are not recommending any changes at this time. If radar enforcement were applied to this street, the existing 25 mph limit would soon be described as unrealistic, even by the residents. We suspect a rigidly enforced 30 mph limit on this street would substantially lower prevailing speeds. DAVONA DRIVE: tn 1782, the City Council authorized stop signs at two intersections along Davona Drive. Since their installation, there continue to be complaints of speeding. Over the years, traffic engineers have noted that the use of stop signs for speed control is ineffective. Motorists tend to roll through unwarranted stop signs and then make up for lost time by going even faster. In the case of Dauona Drive we have not made stop sign compliance checks but in our most recent radar checks we have noted that speeds have not reduced since the placement of the stop signs. We made a total of 12 radar checks at different times and locations along Davona Drive and found that the average speed is still about 30 mph and the speed driven at or below by 85 percent of the motorists is still about 35 mph. With these findings, we cannot recommend any additional stop signs nor do we recommend a change in speed limits. It is felt that traffic conditions on this street would be susceptible to improvement by radar enforcement.