HomeMy WebLinkAbout2007-06-04; Traffic Safety Commission; ; Establish a prima facie speed limit upon Alicante Road from Poinsettia Lane to Gateway Road( (
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: June 4, 2007
LOCATION: Alicante Road, Poinsettia Lane to Gateway Road
INITIATED BY: Deputy City Engineer, Transportation
ITEMNO.6C
REQUESTED ACTION: Establish a prima facie speed limit upon Alicante Road from
Poinsettia Lane to Gateway Road
BACKGROUND:
No prima facie speed limit has been established on Alicante Road northerly of
Poinsettia Lane. The road was constructed within the past two years as a requirement of
the Bressi Ranch project.
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. 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. Traffic laws established on the basis of the
behavior of the reasonable and prudent motorist are found to be the most successful.
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.
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.
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CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: June 4, 2007
( continued)
ITEMNO. 6C
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 (85 th 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 percentile 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
85thpercentile 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.
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.
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CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: June 4, 2007
( continued)
ITEMNO. 6C
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.
DATA:
Alicante Road north of Poinsettia Lane serves residential and industrial uses and is
0.96 miles in length. The road has a curb-to-curb width of 40 feet south of Town Garden
Road and 48 feet north of Town Garden Road. One driveway has been constructed on
Alicante Road. Street lights have been constructed on both sides of the road. A non·-
contiguous sidewalk is provided along the east side of Alicante Road and on about
one-third of the west side of Alicante Road. On the west side from Town Garden Road to
Gateway Road, the sidewalk is contiguous to the curb and gutter. The remaining west ·
side is served by a non-contiguous walking trail for pedestrians.
As indicated on Table A, daily two-way traffic volumes range from 766 vehicles near
Poinsettia Lane to 838 vehicles south of Gateway Road based upon counts obtained in
March 2007. For the two-year period ending April 30, 2007, there have been no reported
collisions on Alicante Road north of Poinsettia Lane.
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CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: June 4, 2007 ITEMNO. 6C
( continued)
North County Transit District has established a bus stop on Alicante Road. This stop is
located northerly of Town Garden Road on the east side.
The future 32 acre Alga Norte Community Park will be constructed on the northwest
comer of the Alicante Road/Poinsettia Lane intersection. Final plans for the park are
being prepared with construction of the project expected in Fall 2007 and the park
opening in 2009.
DATE
3/14/07
3/14/07
TABLE A
24-HOUR TRAFFIC VOLUMES
ALICANTE ROAD
. 24-HOUR-ADT
LOCATION ·NIB SIB TOTAL
n/o Poinsettia Lane 326 440 766
s/o Gateway Road 448 390 838
Alicante Road follows a curvilinear alignment and has roadway grades that vary between
1.50% and 9.03%. On-street parallel parking is allowed south of Town Garden Road.
At its intersection with Poinsettia Lane, Alicante Road is controlled by a traffic signal.
Alicante Road terminates in a T-intersection configuration at Gateway Road and is
controlled by a stop sign at that location.
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 (FHW A'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 85thpercentile 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:
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CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: June 4, 2007
( continued)
ITEMNO. 6C
(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;
(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 Alicante Road from
Poinsettia Lane to Gateway Road. Results of the speed survey, contained within the
Engineering and Traffic Survey that was conducted on Alicante Road, are summarized in
Table B.
TABLEB
SPEED SURVEY DATA FOR ALICANTE ROAD
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.
The posted speed limit on Alicante Road southerly of Poinsettia Lane is 40 miles per
hour.
RECOMMENDATION:
Upon review of the results of the Engineering and Traffic Survey, the Traffic Safety
Coordinating Committee recommends establishing a 40 mile per hour prima facie speed
limit upon Alicante Road from Poinsettia Lane to Town Garden Road.
NECESSARY CITY COUNCIL ACTION:
An ordinance will be required to be adopted by the City Council to establish the 40 mile
per hour prima facie speed limit upon Alicante Road, as recommended.
PROPOSED
SPEED ZONE
PROJECT NAME
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LOCATION MAP
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GATEWAY RD.
TOWN GARDEN RD.
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PYRITE AVE.
PROPOSED SPEED ZONE
NOT TO SCALE
EXHIBIT
AL/CANTE ROAD -POINSETTIA LANE TO GATEWAY ROAD 1
DRAVrN BY: SCOTT EVANS, CARLSBAD ENGINEERING DEPT. J '28 07 C: TRAfflC SPEED ZONES SPEEO ZONE-AUCANTE ROAD NORTH 2.0KG
( CITY OF CARLSBAD l
ENGINEERING AND TRAFFIC SURVEY
STREET: Alicante Road
LIMITS: Gateway Road to Poinsettia Lane
A. Prevailing Speed Data:
Date of Speed Suivey
Location of Speed Suivey
85th Percentile
10 MPH Pace
Percent in Pace
Posted S eed Limit
B. Midblock Accident History:
(5/01/05 through 4/30/07)
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 Parking
Other
D. Roadway Factors:
Circulation Element Street Classification
Length of Segment
Roadway Width
Number of Lanes
Vertical Alignment
Horizontal Alignment
Sidewalks
Driveways
Street Li htin
Direction: Northbound/Southbound
5/08/07
500 Feet n/o Pyrite Avenue
45MPH
37 to 47 MPH
75%
No Posted S eed Limit
None
None
None
1.89 (2004 Rate for Same Type of Roadway)
838 -South of Gateway Road (3/14/07); 766-North of Poinsettia Lane (3/14/07)
Stop Sign Control at Gateway Road & Town Garden Road; Traffic Signal at Poinsettia LcJne
Light
Bike Lane on Each Side n/o Town Garden Road; No Bike Lanes s/o Town Garden Road
Parking Prohibited on Both Sides n/o Town Garden Road; Parking Allowed on Each
Side s/o Town Garden Road
Bus Route North of Town Garden Road
Unclassified
0.96 Mi.
40 Feet s/o Town Garden Road; 48 Feet n/o Town Garden Road
One Lane Each Direction
Roadway Grades Vary from 1.50% to 9.03%
Cuivilinear
Sidewalk on Entire East Side and Approximately One Third of West Side;
Walking Trail on Remainder of West Side
One Driveway
Street Lights on Each Side
E. Special Conditions: Travel lanes are separated by a double-yellow centerline south of Town Garden Road and a two-way
left-turn lane north of Garden Road.
G. Remarks/Conditi • rent: Pedestrian and vehicular volumes as well as bicycle traffic will increase when
ad'acent elementa ust, 2007 and ad·acent residential develo ins to be occu ied.
H. Traffic Engineer's Recommendation (Explanation): This speed zone satisfies the conditions of Seetion 627 of the California
Vehicle Code and has been prepared and evaluated in accordance with the California Manual on Uniform Traffic Control Devices
for Streets and Highways (FHWA's MUTCD 2003 Revision 1, as amended for use in California) with respect to design and
prevailing speeds, accident records, pedestrian and bicyclist safety, intersection and driveway spacing, and roadside and traffic
conditions not readil a arent to the driver. As eed limit ostin of 40 MPH is found to be a ro riate and ·ustified.
="'"""""="""""',.,,-,,;corll
CITY OF CARLSBAD
SPEED SURVEY
DATE: 5/08/07 TIME: 11 :30 AM TO 2:40 PM TOTAL VEHICLES:
WEATHER: Sunny & Hot -~'--------------CRITICAL SPEED:
LOCATION: Alicante Road~500' n/o Pyrite Avenue VEHICLES IN PACE:
OBSERVER/RECORDER: J. Gale/M. Rehfeldt PACE SPEED(S):
NONE
POSTED SPEED LIMIT
SOUTHBOUND
DIRECTION OF TRAVEL
MPH # % E # % %tile % #
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50 X
49 X X
48 X X
47 X X X
46 X X X X
45 X X
44 X X X X X X
43 X X
42 X X X X X X
41 X X X X
40 X X X X
39 X X X X X
38 X X X
37 X X
36
35 X X X
34 X
33
32
31
30
29
28
27
26
25
24
23
22
21
1 2 1 1 100
2 4 2 2 99
2 4 3 3 97 2 1
3 6 5 5 94 4 2
4 8 4 4 89
2 4 4 4 85 4 2
6 12 9 9 81 6 3
2 4 6 6 72 8 4
6 12 9 9 66 6 3
4 8 8 8 57 8 4
4 8 9 9 49 10 5
5 10 11 11 40 12 6
3 6 8 8 29 10 5
2 4 7 7 21 10 5
2 2 14 4 2
3 6 5 5 12 4 2
1 2 3 3 7 ·4 2
1 1 4 2 1
2 2 3 4 2
1
1 1 1 2 1
Engineering Department
Transportation Division
100
45 MPH
75 %
37 TO 47 MPH -----
NORTHBOUND
DIRECTION OF TRAVEL
MPH
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
X 48
X X 47
46
X X 45
X X X 44
X X X X 43
X X X 42
X X X X 41
X X X X X 40
X X X X X X 39
X X X X X 38
X X X X X 37
X X 36
X X 35
X X 34
X 33
X X 32
31
X 30.
29
28
27
26
25
24
23
22
21