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Home My WebLink About2016-06-06; Traffic Safety Commission; ; Establish a prima facie speed limit upon La Costa Avenue from Camino de los Caches to Circulo SequoiaC CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: June 6, 2016 ITEM NO. 6A2 LOCATION: INITIATED BY: La Costa Avenue -Camino de los Caches to Circulo Sequoia City Traffic Engineer REQUESTED ACTION: Establish a prima facie speed limit upon La Costa Avenue from Camino de los Caches to Circulo Sequoia. BACKGROUND: This portion of La Costa Avenue, east of Camino de los Caches, opened to traffic around late 2003/early 2004 and a speed limit should be established. The roadway section directly to the west, between Rancho Santa Fe Road and Camino de los Caches, has a posted speed limit of 45 mph. (see attached Exhibit 1) SETTING SPEED LIMITS: In the City of Carlsbad, the predominant practice for managing speed is by legally establishing a speed limit according to Caltrans criteria and then posting the speed limit upon the road with regulatory signs in compliance with the California MUTCD. Police enforcement is used to cite violators that exceed the posted speed limit. A fundamental tenet is that laws are enacted to protect the majority of the public by regulating the unsafe or unreasonable actions of the few. When speed limits have been reasonably set, the enforcement efforts of the Carlsbad Police Department are more effective. Speed limits are established by law when the City Council adopts an ordinance and the speed limit is posted on the roadway to indicate the maximum reasonable speed for a driver to operate a vehicle under ideal conditions in off-peak free flowing conditions. Among many factors, the three most persuasive issues considered when setting a realistic, or rational, speed limit are: 1. 85th percentile speed (critical speed) 2. Collision history 3. Conditions that may not be readily apparent to the driver The 85th percentile speed, often referred to as the critical speed, is the speed which 85% of the drivers are traveling at or below. The premise implied in speed zoning is that the majority of drivers are operating their vehicles at or below the 85th percentile speed. Drivers that operate their vehicle at speeds higher than the 85th percentile speed are considered to be driving at an excessive speed. A comprehensive review of the collision history on a roadway is another important element in the process to establish a speed limit because this information is not readily C apparent to a driver. In the collision analysis, factors such as collision frequency, type, severity, road conditions, road geometry, lighting conditions, and spatial distribution of the collisions are all considered. The review of collisions will also reveal if there is a high incidence of speed-related collisions on the road at specific locations. However, absent a significant collision history attributed to speed, it may be concluded that drivers are operating their vehicle in a reasonable and prudent manner at a speed at or below the critical speed used to establish the speed limit. Speed limits should not be lowered for conditions that are readily apparent to the driver. For unusual conditions or conditions not readily apparent to motor vehicle operators, appropriate warning signs can be installed. Voluntary public compliance with the posted speed limit is the goal when determining a realistic prima facie speed limit to post on a roadway. The realistic speed limit takes into consideration the normally competent and careful actions of a reasonable driver and provides for the regulation of unreasonable behavior by a few individuals. A posted speed limit should be readily accepted by drivers, be fair and reasonable, be related to risk on the roadway, be determined by the majority of drivers, and one that has a factual foundation. Posted speed limits reflect a balance of the various factors specific to the roadway. As a result, roadway safety can be improved and community concerns about traffic speed are appropriately and legally addressed. BASIS OF ACTION: DATA: The proposed speed limit for the road segment discussed in this report is regulated by section 22357(a) of the California Vehicle Code: "Whenever a local authority determines upon the basis of an engineering and traffic survey that a speed greater than 25 miles per hour would facilitate the orderly movement of vehicular traffic and would be reasonable and safe upon any street other than a state highway otherwise subject to a prima facie limit of 25 miles per hour, the local authority may by ordinance determine and declare a prima facie speed limit of 30, 35, 40, 45, 50, 55, or 60 miles per hour or a maximum speed limit of 65 miles per hour, whichever is found most appropriate to facilitate the orderly movement of traffic and is reasonable and safe. The declared prima facie or maximum speed limit shall be effective when appropriate signs giving notice thereof are erected upon the street and shall not thereafter be revised except upon the basis of an engineering and traffic survey. This section does not apply to any 25 mile per hour prima facie limit which is applicable when passing a school building or the grounds thereof or when passing a senior center or other facility primarily used by senior citizens." This portion of La Costa Avenue has one travel lane in each direction and extends from Camino de los Coches on the west to Circulo Sequoia, its terminus, on the east. Bike lanes were painted on the roadway on May 4, 2015. The road follows a curvilinear alignment with grades ranging from 2% to 7.8% and has a curb-to-curb width which varies between 40 feet and 52 feet. Travel lanes are separated by a raised, landscaped median between Circulo Sequoia and Calle Pera. The remainder of the road has a C double-yellow centerline. The intersections at Camino de los Caches, Calle Pera, and Sitio Lima are minor-street STOP controlled. Adjacent land use is single-family residential and open space. Access to a pedestrian trail is also available. Nearby land uses include multi-family residential as well as a church, community park, high school, and community shopping center. On January 27, 2016, a traffic count was obtained on La Costa Avenue to measure the two-way, 24-hour average daily traffic volume. The recent count data is indicated on Table A. Staff reviewed the Police Department traffic collision reports for the two-year period from April 1, 2014 through March 31, 2016. During that time there was one reported traffic collision which involved a bicyclist violating the right-of-way of a motorcyclist. As indicated on Table B, staff conducted a speed survey on La Costa Avenue on June 2, 2015 to obtain data to calculate the critical speed of vehicles. The critical speed, commonly called the 85th percentile speed, is the free flowing speed at which 85 percent of the vehicles are traveling at or below. A sample of 100 vehicles was measured to determine the critical speed. The critical speed is an important factor required to be considered in the evaluation of the appropriate prima facie speed to post upon a roadway. The pace speed is the 10 mile per hour range of speeds that contain the highest number of observed vehicles. TABLE B SPEED SUR TA 6/2/15 300' e/o Camino de las Caches EB/WB 37 28-38 83% RECOMMENDATION: Based upon the results of the Engineering and Traffic Survey, the Traffic Safety Coordinating Committee recommends establishing a 35 mile per hour prima facie speed limit upon La Costa Avenue from Camino de las Caches to Circulo Sequoia. NECESSARY CITY COUNCIL ACTION: An ordinance will be required to be adopted by the City Council to establish the 35 mile per hour prima facie speed limit upon La Costa Avenue from Camino de las Caches to its terminus at Circulo Sequoia, as recommended. NOT TO SCALE PROJECT NAME LOCATION EXISTING 45 MPH SPEED ZONE SITE MAP PROPOSED 35 MPH SPEED ZONE PROPOSED 35 MPH SPEED ZONE LA COSTA AVENUE -CAMINO DE LOS COCHES TO CIRCULO SEQUOIA EXHIBIT 1 PI.OTJED Bl! SCOTT EVANS Pl.OT DAIE5/26/16 PAT/Hk\PUBUC IIIJRKS\1RNISl'ORTA»ON\1RAFFIC DIMSWN\1RAmC lV'EJIA»ONS\AUTllCAD\GALE\2016 lllJRK alDERS\LDCAnON MAPS\1.A COSTA Al£NIIE LDCA»ON MAP.DIIC C CITY OF CARLSBAD ::) ENGINEERING AND TRAFFIC SURVEY STREET: La Costa Avenue LIMITS: Camino de los Coches to Circulo Sequoia A. Prevailing Speed Data: Date of Speed Survey Location of Speed Survey 85th Percentile 10 MPH Pace Percent in Pace B. Accident History: (4/01/14 through 3/31/16) Speed-Related Accidents Pedestrian and/or Bicycle Accidents Total Accidents C. Traffic Factors: Average Daily Traffic Traffic Controls Pedestrian/Bicycle Traffic Bicycle Lanes On-Street ParkinQ D. Roadway Factors: Circulation Element Street Classification Length of Segment Roadway Width Number of Lanes Vertical Alignment Horizontal Alignment Sidewalks Driveways Street Liahtina FACTORS Direction: Eastbound/Westbound 6/02/15 300 Feet e/o Camino de las Caches 37MPH 28 to 38 MPH 83% 0 1 1 2,500 (1/27/16) Stop Sign Control at Circulo Sequoia Moderate Bicycle Lane on Each Side ParkinA Prohibited on Each Side Unclassified 0.22 Mi. 52 Feet (Curb-to-Curb) One Lane Each Direction Roadway Grades Vary from 2.01 % to 7.84% Curvilinear: Three 350-foot Radius Curves Sidewalk on Each Side One Driveway Street Lights on Each Side E. Special Conditions: Travel lanes are separated by a raised, landscaped median between Circulo Sequoia and Calle Pera. The remainder of the road has a double-vellow centerline. F. Adjacent Land Uses: Single-Family Residential, Commercial Shopping Center, Open Space, Pedestrian Trail G. Remarks/Conditions Not Readilv A--arent: West of this seament the roadwav has a oosted soeed limit of 45 miles oer hour. H. Traffic Engineer's Recommendation (Explanation): This speed zone satisfies the conditions of Section 627 of the California Vehicle Code and has been prepared and evaluated in accordance with the California Manual on Uniform Traffic Control Devices, effective November 7, 2014, with respect to design and prevailing speeds, accident records, pedestrian and bicyclist safety, intersection and driveway spacing, and roadside and traffic conditions not readily apparent to the driver. A speed limit oostina of 35 MPH is found to be annrooriate and iustified. I. Approvals: □,Recertification of existing speed zone per Sections 22357, 22358 and 40802 of the California Vehicle Code. lll'Establishment of new speed zone.~ Approved ~~ s t"k) -rr. Doug Bils City Traffic ngineer CATR2279 NOTE: Appropnate speed survey Is attached hereto and made a part hereof. DATE: 6/02/15 TIME: 9:30 AM TO WEATHER: Sunny & Mild CITY OF CARLSBAD SPEED SURVEY 10:50 AM TOTAL VEHICLES: CRITICAL SPEED: LOCATION: La Costa Ave.~300' e/o Camino de las Caches VEHICLES IN PACE: OBSERVER/RECORDER: J. Gale ---------PACE SPEED(S): EASTBOUND DIRECTION OF TRAVEL MPH # % I:# % %tile % # 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 X 39 X X X 38 X X X 37 X X X X 36 X X X X X 35 X X 34 X X X X X X X 33 X X X 32 X X X X X 31 X X 30 X X X X X 29 X X X X X X- 28 X X 27 26 X X 25 24 23 22 21 1 2 3 3 100 4 2 3 6 4 4 97 2 1 3 6 5 5 93 4 2 4 8 8 8 88 8 4 5 10 10 10 80 10 5 2 4 3 3 70 2 1 7 14 14 14 67 14 7 3 6 6 6 53 6 3 5 10 8 8 47 6 3 2 4 9 9 39 14 7 5 10 8 8 30 6 3 6 12 11 11 22 10 5 2 4 6 6 11 8 4 2 2 5 4 2 2 4 3 3 3 2 1 Public Works Department Traffic and Mobility Division 100 37 MPH ----------- 83 % ----------- 28 TO 38 MPH ---------- WESTBOUND DIRECTION OF TRAVEL MPH 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 X X 40 X 39 X X 38 X X X X 37 X X X X X 36 X 35 X X X X X X X 34 X X X 33 X X X 32 X X X X X X X 31 X X X 30 X X X X X 29 X X X X 28 X X 27 X 26 25 24 . 23 22 21