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Home My WebLink About2008-02-04; Traffic Safety Commission; ; Establish a prima facie speed limit upon Lionshead Avenue from Melrose Drive to the east city limit( ( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: February 4, 2008 LOCATION: INITIATED BY: Lionshead A venue, Melrose Drive to east city limit City Engineer ITEMNO. 6B REQUESTED ACTION: Establish a prima facie speed limit upon Lionshead Avenue from Melrose Drive to the east city limit. BACKGROUND: Lionshead A venue, an industrial street, was opened to traffic in 2006. Industrial lots continue to be developed and no prima facie speed limit has been established upon Lionshead A venue. SETTING SPEED LIMITS: Optimal mobility is enhanced and overall traffic flow improved when drivers are operating their vehicles at a speed that is reasonable and safe. It is generally acknowledged that the control of speed can be a significant factor in influencing and improving roadway safety. 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. Most drivers operate vehicles in a reasonable manner. Therefore, traffic laws established on the basis of the behavior of the reasonable and prudent motorist are found to be the most successful. As a result, speed limits that are considered credible and enforceable will help enhance traffic safety and the operating efficiency on the roadway and achieve driver compliance. Roads in Carlsbad are designed in accordance with engineering standards to satisfy the goals of a safe roadway and to enhance efficient traffic flow. One way to achieve the goals is to establish proper and reasonable speed limits that can be enforced. Speed limits that are reasonable can help to achieve voluntary compliance by the majority of drivers without need for the presence of a police officer. Laws and/or the establishment of speed zones that arbitrarily restrict travel by the majority of motorists can lead to wholesale violations of the posted speed limit. For a speed limit to be considered effective, drivers must believe that the posted speed limit is safe and proper. ( ( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: February 4, 2008 ( continued) ITEMNO. 6B In the City of Carlsbad, the predominant practice for managing speed is by legally establishing a prima facie speed limit and then posting the speed limit upon the road with regulatory signs. A prima facie speed limit recognizes that conditions change throughout the day and there is no one safe speed for all the conditions that may be present upon the roadway. 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 law enforcement officers and the courts have confidence that speed limits have been set on a reasonable basis, their enforcement efforts are more effective. Nationally recognized vetted practices and guidance per standards and procedures in the Federal Highway Administration's national Manual on Uniform Traffic Control Devices 2003 Edition are considered when setting speed limits. In California, this manual is titled the California Manual on Uniform Traffic Control Devices. The most common method of establishing speed limits incorporates traffic engineering principles and other factors, such as using the results of a speed survey, into the Traffic and Engineering Survey. Prima facie 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. Critical speed (85th percentile speed) 2. Collision history 3. Conditions that may not be readily apparent to the driver The premise implied in sReed zoning is that the majority of drivers are operating their vehicles at or near the 85 hpercentile speed. Drivers that operate their vehicle at speeds higher than the 85th percentile speed should be the focus of the police. An important speed zoning concept is that the disparity in speed between vehicles on the road is reduced when prima facie speed limits are established at or near the 85th percentile speed and, as a result, safety is enhanced. Also, a speed limit that is established based upon the 85th percentile speed will increase driver respect for the speed limit sign. Only those signs that have the respect of the roadway user will have a positive effect to control 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 there is a high incidence of speed-related collisions on the road at specific locations. Absent a significant collision history attributed to speed, it can be concluded that drivers are operating their vehicle in a reasonable and prudent manner at the speed they chose to drive. The installation of a speed limit sign does not automatically decrease accident rates nor increase roadway safety. Speed limits should not be lowered for conditions that are readily apparent and the speed limit signs are not used as intersection, curve or hazard warning devices. For the unusual conditions or conditions not readily apparent to drivers, appropriate warning signs are installed. ( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: February 4, 2008 ( continued) ITEMNO. 6B Design factors such as the geometric elements of the road, sight distance, or other factors may have a significant impact on the free flowing speed chosen by drivers. This driver chosen speed, in tum, is considered when establishing a prima facie speed limit. A number of factors may be considered when establishing a prima facie speed limit. The 2003 MUTCD lists such factors as: A. Road characteristics, shoulder condition, grade, alignment, and sight distance; B. The pace speed; C. Roadside development and activity; and D. Reported crash experience for at least a 12-month period. 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 determining a realistic prima facie speed limit to establish. 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 is improved and community concerns about traffic speed are addressed. DATA: Lionshead A venue has one traffic lane in each direction and is not classified on the Circulation Element of the General Plan. The road is 0.86 miles in length and has a curb-to-curb width of 52 feet, meeting Carlsbad standards for an industrial road. A bicycle lane is provided on both sides of Lionshead Avenue. As a result, on-street parking is prohibited on both sides of the street. At its terminus with Melrose Drive, Lionshead A venue is controlled by a traffic signal. Twenty-six driveways providing access to industrial lots have been constructed on Lionshead A venue to serve existing and future business establishments. Approximately midway on Lionshead A venue, Eagle Drive intersects Lionshead A venue in a T-intersection configuration. At this intersection, Lionshead A venue is uncontrolled. ( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: February 4, 2008 ITEMNO. 6B ( continued) Lionshead A venue has several horizontal curves but follows a generally straight alignment and has_roadway grades that vary between 1.0% to 8.0%. Based upon traffic counts obtained in January 2008, two-way total traffic volumes on Lionshead A venue range from 2,869 to 3,055. The directional distribution of traffic volumes on Lionshead Avenue is indicated in Table A. TABLE A 24-HOUR TRAFFIC VOLUMES LIONSHEAD AVENUE East of Melrose Drive 1,020 1,650 3,055 East of Ea le Drive 1,343 1,526 2,869 There has been one reported collision on Lionshead Avenue in the two-year period ending November 30, 2007. This collision was speed-related. The 85th percentile speed has been determined throughout the United States to generally conform to a safe and reasonable speed limit. The California Manual on Uniform Traffic Control Devices (FHWA's MUTCD 2003 Revision 1, as amended for use in California) provides guidance when a speed limit is to be posted. It states that "the speed limit should be established at the nearest 10 km/h (5 mph) increment to the 85th percentile speed. However, in matching existing conditions with the traffic safety needs of the community, engineering judgment may indicate the need for a further reduction of 10 km/h (5 mph)." California Vehicle Code section 627 defines the term "Engineering and Traffic Survey" and lists its requirements, as follows: 627. ( a) "Engineering and traffic survey," as used in this code, means a survey of highway and traffic conditions in accordance with methods determined by the Department of Transportation for use by state and local authorities. (b) An engineering and traffic survey shall include, among other requirements deemed necessary by the department; consideration of all of the following: (1) Prevailing speeds as determined by traffic engineering measurements. (2) Accident reports. (3) Highway, traffic, and roadside conditions not readily apparent to the driver. ( c) When conducting an engineering and traffic survey, local authorities, in addition to the factors set forth in paragraphs (1) to (3), inclusive, of subdivision (b) may consider all of the following: (1) Residential density, if any of the following conditions exist on the particular portion of highway and the property contiguous thereto, other than a business district; ( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: February 4, 2008 ( continued) ITEMNO. 6B (A) Upon one side of the highway, within a distance of a quarter of a mile, the contiguous property fronting thereon is occupied by 13 or more separate dwelling houses or business structures. (B) Upon both sides of the highway, collectively, within a distance of a quarter of a mile, the contiguous property fronting thereon is occupied by 16 or more separate dwelling houses or business structures. (C) The portion of highway is longer than one-quarter of a mile but has the ratio of separate dwelling houses or business structures to the length of the highway described in either subparagraph (A) or (B). (2) Pedestrian and bicyclist safety. Staff completed the Engineering and Traffic Survey ( attached) for Lionshead A venue from Melrose Drive to the east city limit. Results of two speed surveys, contained within the Engineering and Traffic Survey prepared for Lionshead A venue, are summarized in Table B. TABLEB SPEED SURVEY DATA FOR L/ONSHEAD AVENUE l ~t: •i t-• .. --:--,-~,-~: ••• ~· ·:: ,', •:~:;_-.·It'' : :=cT,~-:--l(Cliiffr!'f:fl ]I fOO'~fq'~11-: i o/ . : ' . : ~ • •• ; ,•' ••. , .. ' • . 11 ~11x:,r,~l ;~iX[q_rt I tl..D ,,.,, ~,,. ·-· ,, .... ~.:..,JM™u!t!litlfilL~"'-••~·d fm;u-i;,1rllt111-JLJ~U n1ot .l t~'iml!ll_d ~ 1/08/08 900 feet e/o Melrose Drive EB/WB 48 39-49 86 1/08/08 800 feet e/o Eagle Drive EB/WB 50 40-50 80 41-51 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 located 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. RECOMMENDATION: Based upon the results of the Engineering and Traffic Survey, the Traffic Safety Coordinating Committee recommends establishing a 50 mile per hour prima facie speed limit upon Lionshead A venue from Melrose Drive to the east city limit. NECESSARY CITY COUNCIL ACTION: An ordinance will be required to be adopted by the City Council to establish the 50 mile per hour prima facie speed limit upon Lionshead A venue, as recommended. PROPOSED SPEED ZONE ~ NOT TO SCALE LOCATION MAP \ \ I I I \ \ I I I I I I CITY OF VISTA -----'c1T---'Y-OF CARLSBAD LEGEND: @ TRAFFIC SIGNAL r .. ~ i I ~~ • I i . I ! _j t --------------------------..... --..... ~ ~ PROPOSED SPEED ZONE FOR EXHIBIT 1 • LIONSHEAD A VENUE 1 1 PROJECT NAME _______________________________ _..c ( CITY OF CARLSBAD ( ENGINEERING AND TRAFFIC SURVEY STREET: Lionshead Avenue LIMITS: Melrose Drive to East City Limit 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: (12/01/05 through 11/30/07) 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: Circulation Element Street Classification Length of Segment Roadway Width Number of Lanes Vertical Alignment Horizontal Alignment Sidewalks Driveways Street Lighting Direction: Eastbound/Westbound 1/08/08 900 Feet e/o Melrose Drive 48 MPH 39 to 49 MPH 86% No Posted S eed Limit 1 1 0.54 Direction: Eastbound/Westbound 1/08/08 800 Feet e/o Eagle Drive 50 MPH 40 to 50, 41 to 51 MPH 80% No Posted S eed Limit 1.81 (2005 State Rate for Same Type of Roadway) 3,055 -East of Melrose Drive (1/10/08); 2,869 -East of Eagle Drive (1/10/08) Traffic Signal at Melrose Drive Light Bicycle Lane on Each Side Parking Prohibited On Each Side Unclassified 0.86 Mi. 52 Feet (Curb-to-Curb) One Lane Each Direction Roadway Grades Vary from 1 % to 8% Curvilinear Sidewalk on Each Side 26 Driveways Street Li hts on Each Side E. Special Conditions: Travel lanes are separated by a two-way left-turn lane. F. Adjacent Land Uses: Light industrial, vacant industrial lots, strip mall/restaurants, open space, future car wash. G. Remarks/Conditions Not Readily Apparent: Lionshead Avenue is used by motorists as a connection between Melrose Drive and Busines9 Park Drive and provides access to the Carlsbad Raceway Business Park. 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 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 50 MPH is found to be appropriate and ·ustified. -----------i( DATE: 01/08/08 TIME: 1 :25 PM TO WEATHER: Cloudy & Cool CITY OF CARLSBAD SPEED SURVEY 2:40 PM TOTAL VEHICLES: CRITICAL SPEED: LOCATION: Lionshead Avenue ~900' e/o Melrose Drive VEHICLES IN PACE: OBSERVER/RECORDER: M. Rehfeldt ---------PACE SPEED(S): NONE POSTED SPEED LIMIT WESTBOUND DIRECTION OF TRAVEL MPH # % !: # % %tile % # 65 64 63 62 61 60 59 58 57 56 55 54 53 52 X X • 51 X 50 X 49 X X X 48 X X X X X 47 X X X X X 46 X X X 45 X X X X X 44 X X X X X X X 43 X X X X X 42 X X X X X 41 X X 40 X X X X 39 X X 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 2 4 2 2 100 1 2 1 1 98 1 2 2 2 97 2 1 3 6 5 5 95 4 2 5 10 7 7 90 4 2 5 10 8 8 83 6 3 3 6 7 7 75 8 4 5 10 8 8 68 6 3 7 14 13 13 60 12 6 5 10 12 12 47 14 7 5 10 10 10 35 10 5 2 4 7 7 25 10 5 4 8 8 8 18 8 4 2 4 6 6 10 8 4 3 3 4 6 3 1 1 1 2 1 Engineering Department Transportation Division 100 48 MPH ----------- 86 % ----------- 39 TO 49 MPH --------- EASTBOUND DIRECTION OF TRAVEL MPH 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 X 50 X X 49 X X 48 X X X 47 X X X X 46 X X X 45 X X X X X X 44 X X X X X X X 43 X X X X X 42 X X X X X 41 X X X X 40 X X X X 39 X X X 38 X 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 DATE: 01/08/08 TIME: 10:05 AM TO WEATHER: Cloudy & Cool CITY OF CARLSBAD SPEED SURVEY 11 :20 AM TOT AL VEHICLES: CRITICAL SPEED: LOCATION: Lionshead Avenue ~800' e/o Eagle Drive VEHICLES IN PACE: OBSERVER/RECORDER: M. Rehfeldt ---------PACE SPEED(S): NONE POSTED SPEED LIMIT WESTBOUND DIRECTION OF TRAVEL MPH # % ~ # % %tile % # 65 64 63 62 61 60 59 58 57 56 55 54 X 53 X X 52 X X X 51 X X 50 X X X X 49 X X X X X 48 X X X X X X 47 X X X 46 X X X X X X X 45 X X X X X 44 X X X X X 43 X X X 42 X 41 X X 40 X 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 1 2 1 1 100 2 4 2 2 99 3 6 3 3 97 2 4 3 3 94 2 1 4 8 5 5 91 2 1 5 10 8 8 86 6 3 6 12 9 9 78 6 3 3 6 6 6 69 6 3 7 14 13 13 63 12 6 5 10 9 9 50 8 4 5 10 11 11 41 12 6 3 6 7 7 30 8 4 1 2 7 7 23 12 6 2 4 5 5 16 6 3 1 2 5 5 11 8 4 2 2 6 4 2 1 1 4 2 1 2 2 3 4 2 1 1 1 2 1 Engineering Department Transportation Division 100 50 MPH ----------- 80 % ----------- 40 TO 50 MPH --------- 41 TO 51 MPH --------- EASTBOUND DIRECTION OF TRAVEL MPH 65 64 63 62 61 60 59 58 57 56 55 54 53 52 X 51 X 50 X X X 49 ; X X X 48 X X X 47 X X X X X X 46 X X X X 45 X X X X X X 44 X X X X 43 X X X X X X 42 X X X 41 X X X X 40 X X 39 X 38 X X 37 X 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21