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Home My WebLink About2005-08-01; Traffic Safety Commission; ; Establish a prima facie speed limit upon Poinsettia Lane from Black Rail Road to Cassia Road( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: August 1, 2005 LOCATION: INITIATED BY: Poinsettia Lane from Black Rail Road to Cassia Road Deputy City Engineer, Transportation ITEMNO.6B REQUESTED ACTION: Establish a prima facie speed limit upon Poinsettia Lane from Black Rail Road to Cassia Road. BACKGROUND: Poinsettia Lane is a four-lane, divided roadway between Black Rail Road and Cassia Road where termination of Poinsettia Lane is located. Westerly of Black Rail Road, Poinsettia Lane extends to Carlsbad Boulevard and has a posted speed limit of 45 miles per hour from Paseo del Norte to Black Rail 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 and 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 I ( ( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: August 1, 2005 ( continued) ITEMNO. 6B The premise in speed zoning is that the majority of drivers are traveling at or near the 85 th percentile speed. Drivers that operate their vehicle at speeds higher than the 85 th 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 concluded 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: Poinsettia Lane is designated as a major arterial on the Circulation Element of the General Plan. The subject segment is 0.5 miles in length and except for the portion of Poinsettia Lane between A viara Parkway and Black Rail Road that is essentially a two- lane road, the entire length of Poinsettia Lane has been built to city standards with curb and gutter, sidewalk, and streetlights. The missing portion of Poinsettia Lane easterly of Cassia Road, designated as Reach E, is expected to be constructed by a private developer in the three to five year timeframe. ( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: August 1, 2005 ( continued) ITEMNO. 6B The horizontal alignment of the subject segment of Poinsettia Lane is generally straight with one horizontal curve near Ambrosia Lane consisting of a centerline radius of 1,750 feet. The provided radius exceeds the minimum centerline horizontal radius of 1,400 feet that is required for a major arterial roadway. Vertical grades range from a flat 0.40% to 6.32%. A traffic count was obtained on Poinsettia Lane on July 12, 2005 to determine the two- way, average daily traffic volume. At a location east of Black Rail Road, the traffic volume was 5,015 vehicles, well below the expected volume range on a major arterial of 20,000 to 40,000 daily vehicles. Staff conducted a speed survey on Poinsettia Lane on July 7, 2005 to determine the critical speed of vehicles. The critical speed, commonly called the 85 th 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 85 th 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 Poinsettia Lane from Black Rail Road to Cassia Road. Results of the speed survey, included as part of the Engineering and Traffi\:; Survey that was conducted on Poinsettia Lane, are summarized in Table A. Survey Date 7/7/05 TABLE A SPEED SURVEY DATA FOR POINSETTIA LANE I Location at Fisherman Drive Direction EB/WB Critical Speed (MPH) 49 Pace Speed (MPH) 42-52 % in Pace 81 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) ITEMNO. 6B A review of the Police Department collision reports for the two year period from May 1, 2003 through April 30, 2005 found that there were no mid-block collisions reported on the portion of Poinsettia Lane from Black Rail Road to Cassia Road. Poinsettia Lane intersects Black Rail Road as a four-leg, all-way stop controlled intersection. At the intersection of Ambrosia Lane with Poinsettia Lane, right-of-way assignment is controlled with a traffic signal. The Cassia Road/Poinsettia Lane intersection functions as a 90° tum with eastbound Poinsettia Lane narrowed to one lane to negotiate the tum. RECOMMENDATION: Based upon the results of the Engineering and Traffic Survey, the Traffic Safety Coordinating Committee recommends establishing a 45 mile per hour prima facie speed limit upon Poinsettia Lane from Black Rail Road to Cassia Road. NECESSARY CITY COUNCIL ACTION: An ordinance will be required to be adopted by the City Council to establish the 45 mile per hour prima facie speed limit, as recommended. ( NOT TO SCALE PROJECT NAME LOCATION I I I I I / I ~· ·v I / I ( MAP PROPOSED SPEED ZONE POINSETTIA LANE _PROPOSED SPEED ZONE DRAl'rN BY: SCOTT EVANS, CARLSBAD ENG/ilffR/NG DEPT. 7/11 05 C:\1RAmc SPffD ZONES\SPffO ZONE-PO/NSEmA LN2.0WG EXHIBIT 1 STREET: Poinsettia Lane ( CITY OF CARLSBAD ENGINEERING AND TRAFFIC SURVEY LIMITS: Black Rail Road to Cassia Road 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. Midblock 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 Parking Other D. Roadway Factors: Street Classification Length of Segment Roadway Width Number of Lanes Vertical Alignment Horizontal Alignment Sidewalks Driveways Street Li htin None None N.A. Direction: Eastbound/Westbound 7/07/05 At Fisherman Drive 49 MPH 42 to 52 MPH 81% No Posted S eed Limit 2.13 (2003 Rate for 4 or More Divided Lanes) 5,015-East of Black Rail Road (7/12/05) Traffic Signal at Ambrosia Lane; Stop Sign Control at Black Rail Road Light Bicycle Lane on Each Side Parking Prohibited on Each Side Bike Route per Circulation Element of the General Plan Major Arterial 0.50 Mi. 82 Feet (Curb-to-Curb) 2 Lanes Each Direction Roadway Grades Vary from 0.4% to 6.32% Relatively Straight with One 1,750' Radius Curve Sidewalk on Each Side One Existing Driveway and One Future Driveway Street Lights on Each Side E. S ecial Conditions: Eastbound travel lanes are reduced to one lane a roaching Cassia Road. F. Adjacent Land Uses: Fire Station, Single-Family and Multi-Family Residential, Agricultural, Two Churches. Open Space, Future Communit Park. G. Remarks/Conditions Not Readily Apparent: Police motorcycle officers utilize depressions at a midblock location in the raised median for U-turns. H. Traffic. Engineer's Recommendation (Explanation): This speed zone satisfies the conditions of Section 627 of the California Vehicle (??de and has been prepared and evaluated !n a~cordance with th~ Manual on Unifo~m Traffic Control Devices (MUTCD) 2003 Edition as amended by the MUTCD 2003 Cahfornta 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 apparent to the driver. A speed limit posting of 45 MPH is found to be appropriate and justified. I. Approvals: . .._ . : •. ,·.::·· _, O·· .••. ··~ • .• ce .•• ~.ificationofexistiri.·g ..• sp·e.e•.q zone per Sections 22357; 22358 an. d. •.4· 08·· .. o·2·0 .. f.•.·.1 .. h .• e C .. alff.~~nii ···Ve.·• h.it·i• .• •.··.·.C .. ·.·.•.••·•o·j:1•··.e····•··:•.·• :!!;(Establishment of new speed zone. • .· -.• ;; . , ·•.• ... •.• •• •• . ·•·•··•·· .• .••• •• • ••• . • •• • • : ·•· • • . • l'2c ~"+-. •• • , c; >i • ••• ·.·•·· ,., ... -.••,·•.<·•·•···.····•,··•··••·,·.o .. ·•.•··•··.•.•··( . ..:;;\; :--• • Approved ·.• • ••· :r 'r· • .. ;,.. • , t: tV\ ! • Deputy CitY Epgirf r,]Jfi'tj$pprtatio • • ' T\,Sii' ' .,.,, " Appropriate speed survey(s) is/ are attached hereto and made a part hereof. DATE: 7/7/05 TIME: 9:38 AM TO CITY OF CARLSBAD SPEED SURVEY 10:23 AM TOTAL VEHICLES: WEATHER: ...;;C..;.le;._;a_r/_S_u_n_,ny.___ _________ _ CRITICAL SPEED: LOCATION: Poinsettia Lane at Fisherman Drive VEHICLES IN PACE: OBSERVER/RECORDER: T. Cotter PACE SPEED(S): NONE POSTED SPEED LIMIT EASTBOUND DIRECTION OF TRAVEL MPH # % E # % %tile % # 65 64 63 62 61 60 59 58 .57 56 55 54 53 52 1 1 100 2 1 51 X X 2 4 7 7 99 10 5 50 X X X X 4 8 6 6 92 4 2 49 X 1 2 5 5 86 8 4 48 X X X X 4 8 8 8 81 8 4 47 X X X X X X X 7 14 11 11 73 8 4 46 X X X X X X X X 8 16 10 10 62 4 2 45 X X 2 4 6 6 52 8 4 44 ·x X X X 4 8 7 7 46 6 3 43 X X X X 4 8 9 9 39 10 5 42 X X X X 4 8 12 12 30 16 8 41 X X 2 4 2 2 18 40 X X 2 4 4 4 16 4 2 39 X X 2 4 3. 3 12 2 1 38 X X X 3 6 5 5 9 4 2 37 X 1 2 1 1 4 36 .3 3 3 6 3 35 34 33 32 31 30 29 28 27 26 25 24 23 22 .. 21 Engineering Department · Tr~nct"\l"\rl-~til"\n nh,ieinn 100 49 MPH ----------- 81 % -------------42 TO • 52 MPH ---------- WESTBOUND DIRECTION OF TRAVEL MPH 65 64 63 62 61 60 59 58 57 56 55 54 53 X 52 X X X X 51 X 50 X X X 49 X X X 48 X X X 47 X X 46 X X X X 45 X X X 44 X X X X X 43 X X X X X X X X 42 41 X X 40 X 39 X X 38 37 X X X 36 35 34 ·'33 32 31 30 29 28 27 26 25 24 23 22 21