HomeMy WebLinkAbout2014-11-03; Traffic Safety Commission; ; Establish a prima facie speed limit on Hummingbird Road from Batiquitos Drive to Rock Dove StreetCOMMISSION MEETING OF:
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
November 3, 2014 ITEM NO. GD
LOCATION: Hummingbird Road from Batiquitos Drive to Rock Dove Street
INITIATED BY: Sue Jones
1745 Hummingbird Road
Carlsbad, CA 92011
REQUESTED ACTION: Establish a prima facie speed limit on Hummingbird Road from
Batiquitos Drive to Rock Dove Street
BACKGROUND:
Hummingbird Road is a two lane road that functions as a residential collector street
which provides a through-street connection between the Aviara community to the west
and the Seaport community to the east (see Exhibit 1). The easterly segment of
Hummingbird Road from Rock Dove Street to Sanderling Court is currently posted 25
mph meeting the California Vehicle Code definition of a Residence District.
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:
1. 85th percentile speed (critical speed)
2. Collision history
3. Conditions that may not be readily apparent to the driver
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COMMISSION MEETING OF:
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CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
November 3, 2014 ITEM NO. 6D
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
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 a
maximum speed limit of 65 miles per hour, whichever is found most appropriate to
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CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF:
(continued)
November 3, 2014 ITEM NO. GD
DATA:
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 Hummingbird Road is approximately 0.24 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 2% to 12%, 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 adjacent to Tanager Drive. Traffic control on
Hummingbird Road is provided by a STOP sign at Batiquitos Drive on the west end and a
STOP sign at Sanderling Court on the east end. Hummingbird Road qualifies as a
"Residence District" per the California Vehicle Code and is posted with "SPEED LIMIT 25"
signs east of Rock Dove Street.
Surrounding land uses along Hummingbird Road are single and multi-family residential
with access limited to intersections only from Batiquitos Drive to Rock Dove Street.
Traffic volumes are approximately 1,100 vehicles per day, which is in line with 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 August 1, 2012 through July 31, 2014. In that period, there have been no reported
collisions on the subject segment of Hummingbird Road.
Staff conducted a speed survey on this segment of Hummingbird Road 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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COMMISSION MEETING OF:
(continued)
Survey
Date
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
November 3, 2014
TABLE A
SPEED SURVEY DATA
Location Direction
7/24/14 320 ft. east of Tanager Drive EB/WB
ITEM NO. GD
Critical Pace
Speed Speed %in
(MPHI (MPH) Pace
30 21-31 87%
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 BSth 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.
Based on these findings, staff recommends that a speed limit of 30 miles per hour be
established on Hummingbird Road between Batiquitos Drive and Rock Dove Street. See
attached Engineering and Traffic Survey.
RECOMMENDATION:
Based upon the results of the Engineering and Traffic Survey, the Traffic Safety
Coordinating Committee recommends establishing a 30 mile per hour prima facie speed
limit on Hummingbird Road from Batiquitos Drive to Rock Dove Street.
NECESSARY CITY COUNCIL ACTION:
An ordinance will be required to be adopted by the City Council to establish the 30 mile
per hour prima facie speed limit on this segment of Hummingbird Road as
recommended.
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NOT TO SCALE
LOCATION
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1--ll! ffi
MAP
Ii; EXIST. 25 MPH
~ ii!
~ ~ SPEED ZONE
~---____)
UMMJNGBJRD RD.
PROJECT NAME EXHIBIT
ESTABLISH A SPEED LIMIT ON HUMMINGBIRD ROAD
FROM BATIQUITOS DRIVE TO ROCK DOVE STREET
PlOTTrO BY, SCOTT £VANS PLOT OA'/f:,1O/15/14 PA1H,O,\1RANSPORTATION 0£PAR1JIENT\1RAFFIC\MURRAY\SPEED ZONE -HUMMINGBIRO ROAO.OWG
1
C CITY OF CARLSBAD
ENGINEERING AND TRAFFIC SURVEY
STREET: Hummingbird Road
LIMITS: Batiguitos Drive to Rock Dove Street
FACTORS
A. Prevailing Speed Data: Direction: Northbound/Southbound
Date of Speed Suivey 7/24/14
Location of Speed Suivey 320 Feet east of Tanager Drive
85th Percentile 30MPH
10 MPH Pace 21 to 31 MPH
Percent in Pace 87%
B. Accident History:
(8/01/12 through 7/31/14)
Speed-Related Accidents None
Pedestrian and/or Bicyclist Accidents None
Total Accidents None
c. Traffic Factors:
Average Daily Traffic 1,100 -w/o Rock Dove Street (2012)
Traffic Controls Stop Sign Control at Batiquitos Drive
Pedestrian/Bicycle Traffic Light
Bicycle Lanes No Designated Bicycle Lanes Have Been Striped on the Roadway
On-Street Parkinn Parking Allowed on Both Sides Except Adjacent to Tanager Drive
D. Roadway Factors:
Street Classlflcation Unclassified
Length of Segment 0.24 Mi.
Roadway Width 40 Feet (Curb-to-Curb)
Number of Lanes 1 Lane Each Direction
Vertical Alignment Roadway Grades Vary from 2% to 12%
Horizontal Alignment Curvilinear
Sidewalks Sidewalk on Both Sides
Driveways No Driveways
Street Linhtinn Street Lights on Both Sides
E. S-cial Conditions: East of Rock Dove, Humminabird Road aualifies as a "Residence Districf oer the California Vehicle Code.
F-Adiacent Land 11mes: Sinnle and Multi-Familv Residential
G. Remarks/Conditions Not Readily Apparent: Hummingbird Road functions as a residential collector and provides a connection
between the Seanort communitv to the east and the Aviara communitv to the west.
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 spacin~, and roadside and traffic conditions not readily apparent to the driver. A speed limit
oostino of 30 MPH is found to be annroonate and iustified.
I. Approvals:
~
ecertification of existing speed zone per Sections 22357, 22358 and W 802 of the California Vehicle Code.
Establishment of new speed zone. \ .,..,,. .Pi q.;;i-lLJ Approved
DougBils\~, Date
City Traffic ineer
CATR2279
NOTE: Appropriate speed suivey Is attached hereto and made a part hereof.
C
DATE: 7/24/14 TIME: 10:05 AM TO
WEATHER: Sunny & Warm
CITY OF CARLSBAD
SPEED SURVEY
11 :50 AM TOTAL VEHICLES:
CRITICAL SPEED:
LOCATION: Hummingbird Road-320' e/o Tanager Drive VEHICLES IN PACE:
OBSERVER/RECORDER: .:::J·c..:G::.:a::.:le'-------PACE SPEED(S):
EASTBOUND
DIRECTION OF TRAVEL
MPH # '¾ l:# % %tile % # 0
55
64
63
62
61
60
59
56
57
56
55
54
53
52
51
50
49
46
47
46
45
44
43
42
41
40
39
39 X
37
36
35 y
34
33
32 X
31
30
29 X X
28 X X
27 X X
26
25 X X
24 X X
23
22
21
1 2 1 1 100
99
99
2 4 3 3 99 2 1
1 2 2 2 96 2 1
1 2 2 2 2 1
2 4 a 3 92 2 1
1 2 2 2 89 2 1
4 8 9 9 87 10 5
6 1 10 10 78 8 4
6 12 13 13 68 14 7
6 12 9 9 55 6 3
4 8 9 9 46 10 5
6 1 1:< 13 37 14 7
6 12 12 12 24 12 6
3 n 5 5 12 4 2
1 2 4 4 7 6 3
3 3 3 6 3
Transportation Department
Traffic Division
100
-------=3.:::0 ____ MPH
87 % -----=-----21 TO 31 MPH ----=-'--------
WESTBOUND
DIRECTION OF TRAVEL
MPH
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
46
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
X X 30
X 29
y y X X 28
27
X X 26
y y X X 25
y X X 24
23
X 22
X 21