HomeMy WebLinkAbout2014-11-03; Traffic Safety Commission; ; Modify the limits of the existing 40 mph speed zone on Cadencia Street removing the segment from La Costa Avenue to Del Rey Avenue and Reestablish a prima facie speed liCOMMISSION MEETING OF:
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
November 3, 2014
......,
ITEM NO.GE
LOCATION: Cadencia Street from La Costa Avenue to 0.15 mile north of Piragua
Street
INITIATED BY: Mimi Sampson
7555 Cadencia Street
Carlsbad, CA 92009
REQUESTED ACTION: Modify the limits of the existing 40 mph speed zone on Cadencia
Street removing the segment from La Costa Avenue to Del Rey
Avenue and Reestablish a prima facie speed limit of 40 mph on
Cadencia Street from Del Rey Avenue to 0.15 mile north of
Piragua Street.
BACKGROUND:
Cadencia Street is a two lane road that functions as a residential collector street and
provides a through-street connection between La Costa Avenue to the south and
Rancho Santa Fe Road to the east via Camino Junipero. The segment of Cadencia Street
from La Costa Avenue to Del Rey Avenue meets the definition of a Residence District per
the California Vehicle Code and has a prima facie speed limit of 25 mph. It is
recommended that this segment be removed from the current 40 mph Cadencia Street
speed zone (see Exhibit 1).
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:
(continued)
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
November 3, 2014
1. 85th percentile speed (critical speed)
2. Collision history
ITEM NO. GE
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 fade 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)
November 3, 2014 ITEM NO. GE
DATA:
per hour would focilitote 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."
The subject portion of Cadencia Street is approximately 0.43 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 1.5% to 13.7%, has a curb-to-
curb width 40 feet, and is fully improved with curb, gutter, sidewalks and street lights.
There is a single travel lane in each direction with no painted centerline. Parking is
allowed on both sides of the street, except north of Piragua Street where 383 feet of
parking is prohibited on both sides of the street.
Surrounding land uses along this segment of Cadencia Street are single-family
residential, multi-family residential, and Open Space. Traffic volumes on this segment of
Cadencia Street are approximately 1,500 vehicles per day, which is on the upper end of
the City of Carlsbad Street Design Criteria for a local street {200 -2,000 vehicles per
day).
Staff reviewed the Police Department traffic collision reports for the two-year period
from October 1, 2012 through September 30, 2014. In that period, there has been one
reported collision on the subject segment of Cadencia Street.
Staff conducted a speed survey on this segment of Cadencia Street 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.
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r
COMMISSION MEETING OF:
(continued)
Survey
Date
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
November 3, 2014
TABLE A
SPEED SURVEY DATA
Location Direction
9/11/14 at Venado Street NB/SB
ITEM NO. GE
Critical Pace
Speed Speed %in
{MPH} {MPH} Pace
43 34-44 72%
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 from 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 S mph
increment below the 85th percentile speed which, in this case, is 40 miles per hour.
Based on these findings, staff recommends that a speed limit of 40 miles per hour be re-
established on Cadencia Street from Del Rey Avenue to 0.15 miles north of Piragua
Street. See attached Engineering and Traffic Survey.
RECOMMENDATION:
Based upon the results of the Engineering and Traffic Survey, the Traffic Safety
Coordinating Committee recommends re-establishing a 40 mile per hour prima facie
speed limit on the segment of Cadencia Street from Del Rey Avenue to 0.15 miles north
of Piragua Street.
NECESSARY CITY COUNCIL ACTION:
An ordinance will be required to be adopted by the City Council to re-establish the 40
mile per hour prima facie speed limit on this modified segment of Cadencia Street as
recommended.
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LOCATION MAP
NOT TO SCAL[
NEW LIMITS OF
40 MPH SPEED ZONE
REMOVE FROM
40 MPH SPEED ZONE
(TO BE POSTED 25 MPH) .....__ _ __.~
PROJECT NAME EXHIBIT
MODIFY LIMITS OF CADENCIA SPEED ZONE AND
REESTABLISH 40 MPH SPEED ZONE
PLOTTED BY, SCOTT £VANS PLOT DA TE, 10/15/14 PA 711,D, \ JRANSPORTA RON DEPAR7JIENT\ JRAmC\MURRA Y\SPEE!) ZONE -CADENCIA SJREET.DOG
1
r -CITY OF CARLSBAD
ENGINEERING AND TRAFFIC SURVEY
STREET: Cadencia Street
LIMITS: Del Rey Avenue to 0.15 Mile north of Piragua Street
FACTORS
A. Prev11iling S11eed Dat11: Direction: Northbound/Southbound
Date of Speed Survey 9/11/14
Location of Speed Survey At Venado Street
85th Percentile 43MPH
10 MPH Pace 34 to 44 MPH
Percent in Pace 72%
B. Accident History:
(10/01!12 through 9/30/14)
Speed-Related Accidents 0
Pedestrian and/or Bicyclist Accidents 1
Total Accidents 1
C. Traffic Factors:
Average Daily Traffic 1,200-n/o Piragua Street (2014); 1,500-s/o Piragua Street (2005)
Pedestrian/Bicycle Traffic Very Light
Bicycle Lanes No Designated Bicycle Lanes Have Been Striped on the Roadway
On-Street Parking Parking Allowed on Each Side, Except n/o Piragua Street Where 383 Feet of Parking is
Prohibited on Each Side
D. Roadway Factors:
Street Classification Unclassified
Length of Segment 0.43 Mi.
Roadway Width 40 Feet (Curb-to-Curb)
Number of Lanes 1 Lane Each Direction
Vertical Alignment Roadway Grades Vary from 1.5% to 13. 7%
Horizontal Alignment Curvilinear
Sidewalks 600 Feet of Sidewalk Not Constructed on West Side North of Piragua Street
Driveways Residential Driveways on East Side
Street Liahtina Limited Street Lighting
E. s~ial Conditions: School bus ston located 400 feet north of Del Rev Avenue.
F. A"'AAAnt Land ue-s: Sinale and Multi-Familv Residential, Ooen Scace
G. Remarks/Conditions Not Readil" A--arent: The school bus stop mav result in children crossina the roadwav.
H. Traffic Engineer'!! 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
40 MPH is found to be annronriate and iustified.
I. Ap11rova1s:
□ Recertification of existing speed zone per Sections 22357, 22358 andlt)~2 of the California Vehicle Code.
□ Establishment of new speed zone. -~ , J,
10 ~.2 l~ Approved 'no , : """'
Doug Bilse
1
~ Date
City Traffic En 1eer
CATR2279
NOTE: Appropriate speed survey ,s attached hereto and made a part hereof.
DATE: 9/24/14 TIME: 2:20 PM
WEATHER: Sunny & Mild
..... ,..,
TO
CITY OF CARLSBAD
SPEED SURVEY
3:50 PM TOTAL VEHICLES:
CRITICAL SPEED:
LOCATION: Cadencia Street at Venado Street VEHICLES IN PACE:
OBSERVER/RECORDER: J. Gale -~-------PACE SPEED(S):
NORTHBOUND
DIRECTION OF TRAVEL
MPH # % l:# % %tile % #
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
so
49
48
47
46
45
44
43 " 42 " X
41
40 " " X
39
38 " " 37 " X
36
35 • • • y X
34 X X
33
32 X X
31
30
29
28
27 X X ,. X
25
24
23
22
21
1 1 100 2 1
99
1 1 99 2 1
1 1 98 2 1
3 3 97 6 3
3 3 94 6 3
3 3 91 6 3
1 2 6 6 88 10 5
2 4 7 7 82 10 5
2 2 75 4 2
5 10 10 10 73 10 5
2 4 7 7 63 10 5
5 10 9 9 56 8 4
5 10 7 7 47 4 2
3 6 8 8 40 10 5
8 16 9 9 32 2 1
5 10 7 7 23 4 2
1 2 3 3 16 4 2
4 8 4 4 13
2 4 2 2 9
2 4 2 2 7
2 4 2 2 5
3
2 4 2 2 3
1 2 1 1 1
Transportation Department
Traffic Division
100
_____ 4~3:._ ____ MPH
72 % _____ ....:...=;__ ___ _
__ .....::;34.;___T0 __ 4~4'--__ MPH
SOUTHBOUND
DIRECTION OF TRAVEL
MPH
65
64
63
62 .,
60
59
SB
57
56
55
54
53
52
51 y 50
49
48
47
48
45
44
X X 43
X X 42
41
X X X 40
X X X 39
X X ,.
37
X X X 36
35
y 34
y 33
32
31
30
29
28
27 ,.
25
24
23
22
21