HomeMy WebLinkAbout2013-04-01; Traffic Safety Commission; ; Revise the speed limit upon Chestnut Avenue from Pio Pico Drive to El Camino Real from 35 MPH to 30 MPHCOMMISSION MEETING OF:
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
April 1, 2013
LOCATION: Chestnut Avenue from Pio Pico Drive to El Camino Real
INITIATED BY: Deputy Transportation Director
ITEM NO. 6A
REQUESTED ACTION: Revise the speed limit upon Chestnut Avenue from Pio Pico Drive
to El Camino Real from 35 MPH to 30 MPH.
BACKGROUND:
Currently, this portion of Chestnut Avenue is posted at 35 miles per hour. Based on the
recent installation of bicycle lanes on Chestnut Avenue between Monroe Street and
Celinda Drive in 2012 and the resultant narrowing of the travel lanes, staff determined
that a re-evaluation of this speed zone was appropriate. The California Manual on
Uniform Traffic Control Devices (California MUTCD) recommends that speed limits
should be re-evaluated after roadways have undergone a significant change in roadway
characteristics. On March 6, 2013, a new speed survey was conducted that resulted in a
critical speed determination of 33 MPH. Based on the requirements found in the
California Vehicle Code and the California MUTCD, a posted speed limit of 30 MPH was
determined to be appropriate. The narrowing of the travel lanes and installation of the
bicycle lanes was found to have successfully reduced vehicle speeds and staff is
proposing a reduction of the posted speed limit on this portion of Chestnut Avenue
from 35 MPH to 30 MPH.
SETTING SPEED LIMITS:
In the City of Carlsbad, the predominant practice for managing speed is by legally
establishing a speed limit according the criteria set forth by the California Vehicle Code
and the California Department of Transportation (Caltrans) and then posting the speed
limit upon the road with regulatory signs in compliance with the California MUTCD.
Police enforcement is used to cite violators that exceed the posted 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.
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 factors to consider when setting a
realistic, or rational, speed limit are:
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COMMISSION MEETING OF:
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CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
April 1, 2013
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1. 85th percentile speed (critical speed)
2. Collision history
ITEM NO. 6A
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 below 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 is another 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. 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 not readily apparent to motor vehicle
operators, appropriate warning signs can be installed.
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.
BASIS OF ACTION:
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
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CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF:
(continued)
April 1, 2013 ITEM NO. 6A
DATA:
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 o
maximum speed limit of 65 miles per hour, whichever is found most appropriate to
facilitate the orderly movement af traffic and is reasonable and safe. The declared prima
facie ar 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."
The subject portion of Chestnut Avenue from Pio Pico Drive to El Camino Real is
approximately 1.25 miles in length and is unclassified in the Circulation Element of the
Carlsbad General Plan. The road follows a curvilinear alignment with vertical grades
ranging from 0.4% to 9.33% and has a curb-to-curb width between 48 and 51 feet.
There is a single travel lane in each direction separated by a painted centerline. Parking
is allowed on both sides of the street and there are bicycle lanes in both directions. The
bicycle lanes between Monroe Street and El Camino Real were implemented in 2012
with the intention of providing a missing bicycle facility link on Chestnut Avenue
between Carlsbad High School and the El Camino Real corridor. In order to
accommodate the bicycle lanes, the vehicle travel lanes were reduced to approximately
10 feet wide, which staff anticipated to also reduce vehicle traffic speeds. This would
enhance safety near the high school in an area that has had historical speed related
collisions. Traffic control on Chestnut Avenue is provided by ALL-WAY STOP control at
Pio Pico Drive, Highland Drive and Valley Street and traffic signals at Monroe Street and
El Camino Real.
Surrounding land uses along this portion of Chestnut Avenue is primarily residential with
numerous closely-spaced driveways between Pio Pico Drive and Valley Street and
between Monroe Street and Cameo Road. Carlsbad High School occupies the north side
of Chestnut Avenue between Valley Street and Monroe Street. A church occupies the
property on the southwest corner of Chestnut Avenue and Monroe Street. Traffic
volumes vary from approximately 4,500 and 6,700 vehicles per day, which is in line with
the City of Carlsbad Street Design Criteria for a collector street (2,000 -10,000 vehicles
per day).
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COMMISSION MEETING OF:
(continued)
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
April 1, 2013
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'
ITEM NO. 6A
Staff reviewed the Police Department traffic collision reports for the two-year period
from January 1, 2011 through December 31, 2012. In that period, there have been 7
reported collisions on the subject segment of Chestnut Avenue, of which five were
speed-related.
Staff conducted a speed survey on Chestnut Avenue 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.
TABLE A
SPEED SURVEY DATA
3/6/13 At Westhaven Drive EB/WB 33 26-36 88%
The California MUTCD requires that the speed limit be established at the nearest 5 mile
per hour increment of the 85th percentile with the allowance of exercising one of the
following options:
1. The posted speed may be reduced by 5 mph fram the nearest increment of the 85th
percentile speed, in compliance with eve Sections 627 and 22358.5. See Standard
below for documentation requirements.
2. For cases in which the nearest 5 mph increment of the 85th percentile speed would
require rounding up, then the speed limit may be rounded down to the nearest 5
mph increment below the 85th percentile speed, if no further reduction is used. Refer
to eve Section 21400(f).
Exercising Option 2 allows the speed limit to be rounded down to the nearest 5 mph
increment below the 85th percentile speed which, in this case, is 30 miles per hour.
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COMMISSION MEETING OF:
(continued)
RECOMMENDATION:
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
April 1, 2013 ITEM NO. 6A
Based upon the results of the Engineering and Traffic Survey, the Traffic Safety
Coordinating Committee recommends revising the speed limit upon Chestnut Avenue,
from Pio Pico Drive to El Camino Real, from 35 to 30 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 Chestnut Avenue as recommended.
•
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NOT TO SCALE
LOCATION MAP
LEGEND:
@) EXISTING TRAFFIC SIGNAL
@) EXISTING ALL-WAY STOP
! I t ~ .§
~ r--------------------------------------1,l! ! PROPOSED SPEED ZONE
CHESTNUT AVENUE
EXHIBIT
1 t ! ..,__ _______________________________ .,L __ ___J o
CITY OF CARLSBAD
ENGINEERING AND TRAFFIC SURVEY
STREET: Chestnut Avenue
LIMITS: Pio Pico Drive to El Camino Real
FACTORS
A. Prevailing Seeed Data: Direction: Eastbound/Westbound
Date of Speed Survey 3/06/13
Location of Speed Survey At Westhaven Drive
85th Percentile 33MPH
10 MPH Pace 26 to 36 MPH
Percent in Pace 88%
B. Accident Histo!)'.:
(1/01/11 through 12/31/12)
Speed-Related Accidents 5
Pedestrian and/or Bicyclist Accidents 0
Total Accidents 7
C. Traffic Factors:
Average Daily Traffic 4.500 -East of Highland Drive (2009); 6,700 -West of El Camino Real (2009) Traffic Controls All-Way Stop Sign Control at Pio Pico Drive, Highland Drive and at Valley Street, Traffic Signals at
Monroe Street and at El Camino Real
Pedestrian/Bicycle Traffic Significant Due to Several Schools and Churches Nearby
Bicycle Lanes Bicycle Lanes on Both Sides for Entire Length Except North Side from El Camino Real to west of Celinda.
On-Street Parkino Parkino Prohibited on Both Sides East of Cameo Road
D. Roadway Factors:
Circulation Element Street Classification Unclassified
Length of Segment 1.25 Mi.
Roadway Width 48 to 51 Feet (Curb-to-Curb)
Number of Lanes 1 Lane-EB, 2 Lanes-WB from El Camino Real to west of Celinda Drive; 1 Lane Each
Direction Remainder of Roadway
Vertical Alignment Roadway Grades Vary from 0.40% to 9.33%
Horizontal Alignment Curvilinear
Sidewalks Sidewalk on Each Side
Driveways Numerous Closely Spaced Driveways
Street Liohtino Street LiQhtinQ Present
E. Snecial Conditions:
F. Ad;acent Land Uses: Office BuildinQ, Citv Park, Residential, HiQh School, Churches, Open Space
G. Remarks/Conditions Not Readily Aeearent: This is a highly-used school corridor for elementary, junior high, and high school
pedestrians, bicyclists and motorists. Roadway conditions before school and after school are congested with students in the street
and various vehicle turning movements and parking maneuvers. School warning signs have been posted to alert motorists
annroachina the hiah school from each direction.
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,
effective January 13, 2012, 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
30 MPH is found to be annrooriate and iustified.
I. Aeprovals:
□ Recertification of existing speed zone per Sections 22357, 22358 and 40802 of the California Vehicle Code.
□ Establishment of new speed zone.
Approved
Bryan D. Jones TE, PTP, AICP Date
Deputy Director/City Traffic Engineer
CA TR2229
NOTE: Appropriate speed survey ,s attached hereto and made a part hereof.
r
DATE: 3/06/13 TIME: 11:15AM TO
WEATHER: Sunny & Mild
CITY OF CARLSBAD
SPEED SURVEY
11 :55 AM TOTAL VEHICLES:
CRITICAL SPEED:
LOCATION: Chestnut Avenue at Westhaven Drive VEHICLES IN PACE:
OBSERVER/RECORDER: J. Gale -'----------PACE SPEED(S):
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
47
46
45
44
43
42
41
40
39
38
37
36 X
35 X X X
34 X
33 X
32 X X X
31 X X X X X
30 X X X
29 X X X X X X X
28 X X X X X X X X
27 X X X X
26 X X X X X
25 X X X X X X
24 X
23 X X
22
21
1 2 1 1 100
3 6 7 7 99 8 4 1 2 3 3 92 4 2
1 2 9 9 89 16 8
3 6 5 5 80 4 2 5 10 10 10 75 10 5
3 6 8 8 65 10 5 7 14 12 12 57 10 5
8 16 16 16 45 16 8
4 8 9 9 29 10 5
5 10 9 9 20 8 4
6 12 6 6 11
1 2 2 2 5 2 1 2 4 2 2 3 1 1 1 2 1
Transportation Department
Traffic Division
100
33 MPH -----~~----
88 % -----------
26 TO 36 MPH ----------
WESTBOUND
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
X X X X 35
X X 34
X X X X X X X X 33
X X 32
X X X X X 31
X X X X X 30
X X X X X 29
X X X X X X X X 28
X X X X X 27
X X X X 26
25
X 24
23
X 22
21