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Home My WebLink About2005-08-01; Traffic Safety Commission; ; Establish a prima facie speed limit upon Paseo Avellano from Calle Barcelona to Segovia Way( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: August 1, 2005 LOCATION: Paseo Avellano from Calle Barcelona to Segovia Way ITEMNO. 6A INITIATED BY: Sil via Garcia, resident of La Costa Valley in south Carlsbad REQUESTED ACTION: Establish a prima facie speed limit upon Paseo Avellano from Calle Barcelona to Segovia Way. BACKGROUND: Paseo Avellano operates as a two-lane roadway located in La Costa Valley and serves the adjacent residential housing development. It is 0.2 miles in length and functions as a local collector road. SETTING SPEED LIMITS: Mobility is enhanced and overall traffic flow improved when drivers are operating their vehicles at a speed that is reasonable and safe. In fact, the premise of CVC section 22350, Basic Speed Law, is that no person shall drive upon a road at a speed greater than is reasonable and prudent taking into account weather, visibility, and traffic on the road and in no event at a speed that endangers the safety of others. Carlsbad roads are designed using engineering standards to promote the goals of safety on the roadway a.nd efficient traffic flow. One way to achieve the goals is to establish reasonable speed limits that can be enforced. Speed limits that are reasonable help achieve voluntary compliance by the majority of drivers without need for the presence of a police officer. In Carlsbad, the most predominant practice of managing speed is by legally establishing a speed limit and posting the speed limit upon the road with signs. Police enforcement is used to target the most egregious violators of the speed limit. The most common method of establishing speed limits incorporates traffic engineering principles and other factors, such as using the results of a speed survey. The three most persuasive arguments for setting a realistic, or rational, speed limit are: 1. Critical speed (85 th percentile speed) 2. Collision history 3. Conditions that may not be readily apparent to the driver CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: August 1, 2005 (continued) ITEMNO. 6A The premise in speed zoning is that the majority of drivers are traveling at or near the 85th percentile speed. Drivers that operate their vehicle at speeds higher than the 85th percentile speed would be the focus of the police. The disparity in speed of vehicles on the road is reduced when speed limits are established at or near the 85 th percentile speed and this results in enhanced safety. Also, a speed limit that is established based upon the 85 th percentile speed will increase respect for the speed limit sign. Only those signs that have the respect of the roadway user will have an effect in controlling traffic. A review of the collision history on a roadway is an important element in the process to establish a speed limit. The review will reveal if speed-related collisions occur in a high incidence on the road at certain locations. Consequently, factors such as the geometric elements of the road, sight distance, or other factors may have a significant impact on the speed chosen by drivers. Absent a significant collision history as a result of speed, it can be cqncluded that drivers are operating their vehicle in a reasonable and prudent manner at the speed they chose to drive. This driver chosen speed, in tum, is used in establishing a speed limit. As stated, basic speed law requires drivers to operate their vehicle at a speed that takes into account all roadway factors, environmental elements, adjacent land uses, and other traffic on the road. These are, in general, all readily apparent factors. Warning signs placed on the roadway can alert drivers to the presence of an unseen or unanticipated condition. As a result, drivers can operate their vehicle in a reasonable and prudent manner by adjusting speed for the condition that may be encountered. In summary, through the use of engineering, educational, and enforcement techniques, the management of vehicle speed is conducted. Voluntary public compliance with the posted speed limit is the goal when setting a realistic speed limit. 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. DATA: Paseo Avellano is an unclassified street on the Circulation Element of the General Plan. The road has a curb-to-curb width of 40 feet and is constructed to city standards with curb and gutter, sidewalk, and streetlights. Except for a short segment near Segovia Way, no centerline striping has been placed upon Paseo Avellano. As indicated on Exhibit 1, three residential streets intersect Paseo Avellano. Two intersections form a T-intersection and the third is a four-leg intersection. The northerly intersecting street, Camino Serbal, is controlled with a stop sign on both sides of Paseo Avellano. No control has been established for the other two streets at their intersection with Paseo Avellano (see Condition Diagram Exhibit 2). Stop signs have been installed on Paseo Avellano where it intersects both Calle Barcelona and Segovia Way. No intersection control has been placed on Paseo Avellano where it intersects the other three residential streets. ( ( CITY OF CARLSBAD TRAFFIC SAFETYCOMMISSION STAFF REPORT COMMISSION MEETING OF: August 1, 2005 ( continued) ITEMNO. 6A Traffic volumes on Paseo Avellano range from 4,546 vehicles north of Calle Barcelona to 2,857 vehicles south of Segovia Way. These 24-hour, two-way volumes were obtained on June 28, 2005 and June 29, 2005, respectively. Centerline grades range from 1.02% to 7.65% and the road follows a slight curvilinear alignment. There have been no reported mi db lock traffic collisions on Paseo Avellano in the two-year period from May 1, 2003 to April 30, 2005. Staff conducted a speed survey on Paseo Avellano on June 28, 2005 to determine the critical speed of vehicles. The critical speed, commonly called the 85th percentile, is the 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 used to help determine the appropriate prima facie speed to post upon a roadway. The 85th percentile speed has been determined throughout the United States to generally conform to a safe and reasonable speed limit. The five mile per hour increment at or immediately below the 85th percentile is the numerical value that is typically selected for a posted speed limit so as to reflect a realistic and enforceable speed limit. Staff completed an Engineering and Traffic Survey ( attached) for Paseo Avellano that encompasses the road segment from Calle Barcelona to Segovia Way. Results of the speed survey, included as part of the Engineering and Traffic Survey that was conducted on Paseo Avellano, are summarized in Table A .. Survey Date 6/28/05 TABLE A SPEED SURVEY DATA FOR PASEO AVELLANO Location 50 feet north of A venida Cereza Direction NB/SB Critical Speed (MPH) 31 Pace Speed (MPH) 24-34 % in Pace· 91 The pace speed is the 10 mile per hour range of speeds that contain the highest number of observed vehicles. Generally, the critical speed is in the upper range of the pace speed. Sections 22357 and 22358 of the California Vehicle Code authorize local authorities to establish a prima facie speed limit on the basis of the results of an Engineering and Traffic Survey. The Engineering and Traffic Survey considers such factors as the number of collisions that have occurred on the road segment, roadway features, adjacent land uses, driveway locations, traffic volumes, pedestrian volumes, critical speed, horizontal and vertical alignment, stopping sight distance, and conditions that may not be readily apparent to the driver. ( ( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: August 1, 2005 ( continued) RECOMMENDATION: ITEMNO. 6A Based upon the results of the Engineering and Traffic Survey, the Traffic Safety Coordinating Committee recommends establishing a 30 mile per hour p1ima facie speed limit upon Paseo Avellano from Calle Barcelona to Segovia Way. NECESSARY CITY COUNCIL ACTION: An ordinance will be required to be adopted by the City Council to establish the 30 mile per hour prima facie speed limit, as recommended. NOT TO SCALE ( LOCATION MAP I I I AVENIDA CASTANA PROPOSED SPEED ZONE PROJECT NAM[ PASEO AVELLANO PROPOSED SPEED ZONE EXHIBIT 1 ( ( CONDITION DIAGRAM 50 FEET OF DOUBLE YELLOW STRIPE WITH TYPED TWO-WAY YELLOW RETROREFLECTIVE MARKERS (DETAIL 22) +DSN DSN & R1-1 AVENIDA CASTANA SIGN LEGEND: NOT TO SCALE DSN DOUBLE STREET NAME SIGN DSN & R1-1 R1-1 -STOP SIGN LEGEND: ,.... -FIRE HYDRANT -.----SIGN ON TELESPAR POST STOP -STOP PAVEMENT LEGEND WITH LIMIT LINE PROJECT NAM[ PASEO AVELLANO EXHIBIT (CALLE BARCELONA TO SEGOVIA WAY) 2 ( ( CITY OF CARLSBAD ENGINEERING AND TRAFFIC SURVEY STREET: Paseo Avellano LIMITS: Segovia Way to Calle Barcelona A. Prevailing Speed Data: Date of Speed Survey Location of Speed Survey 85th Percentile 10 MPH Pace Percent in Pace Posted S eed Limit B. Mldblock Accident History: (5/01/03 to 4/30/05) Speed-Related Accidents Total Accidents Accidents/Million Vehicle Miles (MVM) California . Statewide Accidents/MVM C. Traffic Factors: Average Daily Traffic Traffic Controls Pedestrian/Bicycle Traffic Bicycle Lanes On-Street Parkin D. Roadway Factors: Street Classification Length of Segment Roadway Width Number of Lanes Vertical Alignment Horizontal Alignment Sidewalks Driveways Street Li htin 0 0 None Direction: 6/28/05 50 Feet North of Avenida Cereza 31 MPH 24to 34 MPH 91% No Posted S eed Limit 2.04 (2003 Rate for Same Type of Roadway) 2,857 -South of Segovia Way (6/29/05); 4,546 -North of Calle Barcelona {6/28/05) Stop Sign Control at Segovia Way and Calle Barcelona Light No Designated Bike Lanes Have Been Striped on Roadway Parking Allowed on Each Side Unclassified 0.2 Mi. 40 Feet (Curb-to-Curb) One Lane Each Direction Roadway Grades Vary from 1.02% to 7.65% Curvilinear Sidewalk on Each Side No Driveways Street Lights on Each Side E. Special Conditions: This portion of Paseo Avellano functions as a collector for the residences located between Levante Street on the north and Calle Barcelona on the south . . F. Ad"acent Land Uses: Sin le-Family Residential, Bike Paths, 0 en S ace G. Remarks/Conditions Not Readily Apparent: Visibility to and from some intersections is limited due to the vertical and horizontal curvature of the roadwa . 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 Manual on Uniform Traffic Control Devices (MUTCD) 2003 Edition as amended by the MUTCD 2003 California Supplement with respect to design and prevailing speeds, accident records, pedestrian and bicyclist safety, intersection and driveway spacing, and roadside and traffic conditions not readily a arent to the driver. A s eed limit ostin of 30 MPH is found to be a ro riate and ·ustified . .. ·.: ·• .. , . TE: Appropriate speed survey(s) is /are attached hereto and made a part hereof. I \ DATE: 6/28/05 TIME: 9:10 AM TO ( CITY OF CARLSBAD SPEED SURVEY 10:20 AM TOTAL VEHICLES: WEATHER: ..;;;S~u.:..;.nn;.;.,y._&--'-M_il_d _________ _ CRITICAL SPEED: LOCATION: Paseo Avellano-50' n/o Avenida Cereza VEHICLES IN PACE: OBSERVER/RECORDER: J. Gale ...;;_;__;_ ______ _ PACE SPEED(S): NONE . POSTED SPEED LIMIT SOUTHBOUND DIRECTION OF TRAVEL MPH # % l: # % %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 39 38· 37 36 35 34 X 33 X X X 32 X X X 31 X 30 X X X X 29 X X X 28 X X X X X X 27 X X X X X 26 X X X X X X 25 X X X X X X 24 X X X 23 X 22 X X X 21 X X X X X 1 2 3 3 100 4 2 3 6 5 5 97 4 2 3 6 5 5 92 4 2 1 2 5 5 87 8 4 4 8 7 7 82 6 3 3 6 6 6 75 6 3 6 12 11 11 69 10 5 5 10 13 13 58 16 8 9 18 18 18 45 18 9 8 16 14 14 27 12 6 3 6 7 7 13 8 4 1 2. 2 2 6 2 .1 3 6 4 4 4 2 1 Engineering Department Transportation Division 100 _ ___ ___,;3~1:.._ ____ MPH 91 % ----------- ___ 2_4 __ To __ 3_4 ___ MPH NORTHBOUND 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 40 39 38 37 36 35 X X 34 X X 33 X X 32 X X X X 31 X X X 30 X X X 29 X X X X X 28 X y X X X X X X 27 X X X X X X X X X 26 X X X X X X 25 X X X X 24 X 23 X 22 21