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Home My WebLink About2011-02-07; Traffic Safety Commission; ; Revise the prima facie speed limit upon Aviara Parkway from Poinsettia Lane to El Camino RealC CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: February 7, 2011 ITEM NO. 6B LOCATION: INITIATED BY: A viara Parkway from Poinsettia Lane to El Camino Real Police Department REQUESTED ACTION: Revise the prima facie speed limit upon Aviara Parkway from Poinsettia Lane to El Camino Real. BACKGROUND: Currently, this portion of A viara Parkway is posted at 40 miles per hour. The Engineering and Traffic Survey on file was approved on December 27, 2007 with speed surveys dated October 9, 2007. Based on the requirements contained in the California Manual on Uniform Traffic Control Devices (MUTCD) and the California Vehicle Code (CVC), this Engineering and Traffic Survey is not considered expired. However, the Police Department has requested that this speed zone be re-evaluated based on recent experiences in court in which speeding cases have been dismissed due to inadequacy of the current Engineering and Traffic Survey. SETTING SPEED LIMITS: Effective July 1, 2009, Caltrans Division Chief Robert Copp signed the Policy Directive to establish the procedure for setting speed limits in California. The changes for setting speed limits are included in the California MUTCD pursuant to authority granted to Caltrans in Section 21400 and 21401 of the California Vehicle Code. The referenced directive clarifies procedures for setting speed limits. Caltrans has incorporated two new standards into the CA MUTCD to help set speed limits in California that are uniform, rational, enforceable by the police, and are supported by the judicial system. Requirements of the new standards as established by Caltrans are: • The speed limit shall be established at the nearest 5 mph increment of the 85 th percentile. • If the 5 mph reduction is applied, the Engineering and Traffic Survey shall document in writing the conditions and justification for the reduced speed limit and be approved by a registered Civil or Traffic Engineer. 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. Police enforcement is used to target the most egregious violators of the 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. Page I CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: ( continued) February 7, 2011 ITEM NO. 6B 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 arguments to consider 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 near the 85th percentile speed. Drivers that operate their vehicle at speeds higher than the 85th percentile speed should be the focus of the police as excessive speed is often a factor in a vehicle collision. A comprehensive review of the collision history on a roadway also is an important element in the process to establish a speed limit. 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. A number of collisions above the expected or normal threshold based upon comparative collision rates may be an indicator of a potential for reducing collisions. 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 the speed they choose to drive. Speed limits should not be lowered for conditions that are readily apparent to the driver and the speed limit signs should not be used as intersection, curve or hazard warning devices. For unusual conditions or conditions that are readily apparent to motor vehicle operators, appropriate warning signs can be installed. 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 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. Page 2 CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: ( continued) February 7, 2011 BASIS OF ACTION: ITEMNO.6B 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." DATA: The subject portion of Aviara Parkway is approximately 2.11 miles in length and is classified as a Secondary Arterial in the Circulation Element of the Carlsbad General Plan. The road follows a curvilinear alignment with grades ranging from 2% to I 0% and has a curb-to-curb width of 82 feet. There are two traffic lanes and a bicycle lane in each direction separated by a raised median. The subject segment has been improved with curb and gutter, sidewalk and street lights on both sides of the roadway. On-street parallel parking is not allowed on the subject road segment. Traffic signals control traffic on Aviara Parkway at Poinsettia Lane, Kestrel Drive, Black Rail Road, Four Seasons Point, Kingfisher Lane, Batiquitos Drive, Ambrosia Lane, Mimosa Drive, Manzanita Street, and El Camino Real. The intersections at Nightshade Road and Towhee Lane are minor-street STOP controlled. Surrounding land use is primarily residential in nature with a golf course, an elementary school, a middle school, a post office and a shopping center located nearby. There is a school crosswalk at the intersection of Ambrosia Lane and Aviara Parkway. School speed limit signs augmented with flashing beacons are installed to alert motorists approaching the intersection from both directions. Traffic counts were obtained on Aviara Parkway on September 21, 2010 and December 1, 2010 to determine the two-way, 24-hour average daily traffic volume. The recent count data is indicated on Table A. Page 3 CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: ( continued) February 7, 2011 TABLE A 24-HOUR TRAFFIC VOLUMES 9/21/10 East of Black Rail Road 6,345 9/21/10 West of Ambrosia Lane 7,076 12/01/10 East of Mimosa Drive 8,185 ITEMNO.6B 6,000 12,345 6,451 13,527 8,077 16,262 Staff reviewed the Police Department traffic collision reports for the two-year period from January 1, 2009 through December 31, 2010. In that period, there have been six reported collisions on the subject segment of Aviara Parkway, of which four were speed- related. The accident rate for Aviara Parkway was found to be 0.27 accidents per million-vehicle-miles, which compares favorably with the statewide average of 1.61 accidents per million-vehicle-miles for the same type of roadway. Staff conducted speed surveys on A viara Parkway on October 6, 2010 to determine the 85th percentile speed. As stated previously, the 85th percentile speed, commonly called the critical speed, is the speed at which 85 percent of the vehicles are traveling at or below. A sample of 100 vehicles was measured to calculate the 85th percentile speed. TABLEB SPEED SURVEY DATA 530' w/o Mimosa Drive 36-46 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. The California MUTCD requires that the speed limit be established at the nearest 5 mph increment of the 85th percentile and that a 5 mph reduction may be applied if the conditions and justification for the lower speed limit are documented in the Engineering and Traffic Survey and approved by a registered Civil or Traffic Engineer. Staff concludes that the nearest 5 mph increment of the 85th percentile speed is 45 miles per hour and that no justification for a 5 mph reduction is hereby presented. Therefore, staff recommends that a speed limit of 45 miles per hour be established on A viara Parkway between Poinsettia Lane and El Camino Real. 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 Page 4 C CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: ( continued) February 7, 2011 ITEM NO. 6B 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. RECOMMENDATION: Based upon the results of the Engineering and Traffic Survey, the Traffic Safety Coordinating Committee recommends revising the prima facie speed limit upon A viara Parkway, from Poinsettia Lane to El Camino Real, from 40 to 45 miles per hour. NECESSARY CITY COUNCIL ACTION: An ordinance will be required to be adopted by the City Council to revise the prima facie speed limit upon A viara Parkway as recommended. Page 5 r .. . . J z <( 0 DR I V E ~ F Vi <( (. ) (. ) 0 ... . J c;: : LL . >- <( ~ ~ a:: :: : , (.! ) (/ ) z F 0 (/ ) w x w a.. w (/ ) I ® ◄ 1- ff i ~ .. . . w w z 0 N C w w 0. . UJ i 0: : : <( 0. . ~ ~ ~ <( > <( _J C CITY OF CARLSBAD :) ENGINEERING AND TRAFFIC SURVEY STREET: Aviara Parkway LIMITS: Poinsettia Lane to El Camino Real FACTORS A. Prevailing Speed Data: Direction: Eastbound/Westbound Direction: Eastbound/Westbound Date of Speed Survey 10/06/10 10/06/10 Location of Speed Survey 400 feet e/o Black Rail Road 0.1 mile w/o Mimosa Drive 85th Percentile 47MPH 44MPH 10 MPH Pace 39 to49 MPH 36 to 46 MPH Percent in Pace 90% 91% Posted Soeed Limit (On Date of Survey) 40MPH 40MPH B. Midblock Accident Histoof (01/01/09 through 12/31117 Speed-Related Accidents 4 Total Accidents 6 Accidents/Million Vehicle Miles (MVM) 0.27 California Statewide Accidents/MVM 1.61 (2008 State Rate for Same Type of Roadway) C. Traffic Factors: Average Daily Traffic 12,345-East of Black Rail Road (9/21/10); 16,262-East of Mimosa Drive (12/01/10) Traffic Controls Traffic Signals at Poinsettia Lane, Kestrel Drive, Black Rail Road, Aviara Resort Drive, Kin~fisher Lane, Batiquitos Drive, Ambrosia Lane, Mimosa Drive, Manzanita Street and El amino Real Pedestrian/Bicycle Traffic Heavy Before and After School in Vicinity of Elementary School/Middle School Bicycle Lanes Parking Prohibited on Each Side On-Street Parking Bicycle Lane on Each Side Other Bike Route per Circulation Element of the General Plan; Raised Landscaped Median D. RoadwaJl Factors: Street Classification Secondary Arterial Length of Segment 2.11 Miles Roadway Width 82 Feet Number of Lanes 2 Lanes Each Direction Vertical Ali~nment Roadway Grades Vary from 2% to 10% Horizontal lignment Curvilinear Sidewalks Sidewalk on Each Side Driveways Two Driveways Street LiQhtinQ Street Lights on Each Side E. sgecial Conditions: A school crosswalk has been installed at Ambrosia Lane. Flashing beacons and warning signs stating S HOOL -SPEED LIMIT 25 MPH -WHEN CHILDREN ARE PRESENT are posted near the Aviara Oaks Elementary School/Middle School zone to alert motorists aooroachinQ from each direction. F. Adjacent Land Uses: Residential, Elementary School, Middle School, Golf Course, Community Shopping Center, Post Office, C::onvalescent Home G. Remarks/Conditions Not ReadilJl Apparent: The design speed of this road is 40 MPH. The road follows a curvilinear alignment in rollinQ, hilly terrain. 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 Caltrans Traffic Operations Policy Directive 09-04 effective July 1, 2009 and the California Manual on Uniform Traffic Control Devices 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 posting of 45 MPH is found to be appropriate and justified. I. Approvals: □ Recertification of existing speed zone per Sections 22357, 22358 and 40802 of the California Vehicle Code. □ Establishment of new speed zone. Approved Traffic Division Manager Date CARCE 56667 Registration expires 6/30/11 NOTE: Appropriate speed survey(s) 1s /are attached hereto and made a part hereof. DATE: 10/06/10 TIME: 1:35 PM TO WEATHER: Partly Cloudy & Mild CITY OF CARLSBAD SPEED SURVEY 2:15 PM TOTAL VEHICLES: CRITICAL SPEED: LOCATION: Aviara Parkway~400' e/o Black Rail Road VEHICLES IN PACE: OBSERVER/RECORDER: J. Gale ---------PACE SPEED(S): 40 MPH POSTED SPEED LIMIT WESTBOUND DIRECTION OF TRAVEL MPH # % E # % %tile % # 65 64 63 62 61 60 59 58 57 56 55 54 53 52 X 51 X 50 49 X X 48 X 47 X 46 X X X 45 X X X X X X X X 44 X X X X X X X X 43 X X X X X X 42 X X X X X X X X 41 X X 40 X X X X 39 X X X 38 X X 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 1 2 1 1 100 1 2 2 2 99 2 1 97 2 4 3 3 97 2 1 1 2 5 5 94 8 4 1 2 7 7 89 12 6 3 6 6 6 82 6 3 8 16 14 14 76 12 6 8 16 15 15 62 14 7 6 12 12 12 47 12 6 8 16 14 14 35 12 6 2 4 7 7 21 10 5 4 8 5 5 14 2 1 3 6 5 5 9 4 2 2 4 4 4 4 4 2 Transportation Department Traffic Division 100 47 MPH ----------- 90 % ----------- 39 TO 49 MPH ---------- EASTBOUND DIRECTION OF TRAVEL MPH 65 64 63 62 61 60 59 58 57 56 55 54 53 52 X 51 50 X 49 X X X X 48 X X X X X X 47 X X X 46 X X X X X X 45 X X X X X X X 44 X X X X X X 43 X X X X X X 42 X X X X X 41 X 40 X X 39 X X 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 C DATE: 10/06/10 TIME: 3:20 PM TO CITY OF CARLSBAD SPEED SURVEY 3:45 PM TOTAL VEHICLES: WEATHER: Partly Cloudy & Mild CRITICAL SPEED: LOCATION: Aviara Parkway~0.1 mile w/o Mimosa Drive VEHICLES IN PACE: OBSERVER/RECORDER: J. Gale ---------PACE SPEED(S): 40 MPH POSTED SPEED LIMIT EASTBOUND DIRECTION OF TRAVEL MPH # % :E # % %tile % # 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 X 47 46 X X 45 X X X X 44 X X X X X X X X 43 X X X X 42 X X X X X 41 X X X X X 40 X X X X X 39 X 38 X X X X X X X 37 X X X 36 X X 35 X X X 34 33 32 31 30 29 28 27 26 25 24 23 22 21 1 2 2 2 100 2 1 1 1 98 2 1 2 4 3 3 97 2 1 4 8 6 6 94 4 2 8 16 10 10 88 4 2 4 8 10 10 78 12 6 5 10 13 13 68 16 8 5 10 8 8 55 6 3 5 10 12 12 47 14 7 1 2 9 9 35 16 8 7 14 14 14 26 14 7 3 6 5 5 12 4 2 2 4 4 4 7 4 2 3 6 3 3 3 Transportation Department Traffic Division 100 44 MPH ----------- 91 % ----------- 36 TO 46 MPH ----- WESTBOUND DIRECTION OF TRAVEL MPH 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 X 48 X 47 X 46 X X 45 X X 44 X X X X X X 43 X X X X X X X X 42 X X X 41 X X X X X X X 40 X X X X X X X X 39 X X X X X X X 38 X X 37 X X 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21