HomeMy WebLinkAbout2007-11-05; Traffic Safety Commission; ; Revise the prima facie speed limit upon Armada Drive from Palomar Airport Road to LEGOLAND Drive( (
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: November 5, 2007
LOCATION:
INITIATED BY:
Annada Drive, Palomar Airport Road to LEGOLAND Drive
City Engineer
ITEMNO. 6B
REQUESTED ACTION: Revise the prima facie speed limit upon Armada Drive from Palomar
Airport Road to LEGOLAND Drive.
BACKGROUND:
A prima facie 35 mile per hour speed limit was established on Armada Drive from
Palomar Airport Road to LEGOLAND Drive in 1997. Subsequent to the date of originally
establishing the prima facie speed limit, the critical speed on the roadway has increased.
Pursuant to guidelines in the California MUTCD, the Armada Drive prima facie speed limit is
a candidate to be raised by five miles per hour.
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: November 5, 2007
( 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 (85 th percentile speed)
2. Collision history
3. Conditions that may not be readily apparent to the driver
The premise implied in speed zoning is that the majority of drivers are operating their vehicles
at or near the 85 th percentile speed. Drivers that operate their vehicle at speeds higher than the
85thpercentile 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: November 5, 2007
( 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:
Armada Drive, a four-lane divided roadway, is not classified on the Circulation Element of
the General Plan. The road is 0.87 miles in length and has a curb-to-curb width that varies
between 68 feet and 72 feet. Armada Drive is controlled by a traffic signal at its intersection
with Palomar Airport Road and terminates on the north at the LEGOLAND roundabout.
A bicycle lane is provided on both sides of Armada Drive with parking allowed on a portion
of the westerly side of the road adjacent to the flower fields. Two traffic lanes in each
direction are separated by either a raised, landscaped median or a striped, two-way left-tum
lane.
Fleet Street, a private road serving office uses and a museum, intersects Armada Drive at two
locations. It is controlled by a stop sign placed on Fleet Street at both intersections with
Armada Drive. Nine driveways have been constructed on Armada Drive to serve existing
business establishments. North County Transit District operates bus service on Armada Drive
with several bus stops provided for transit patrons.
( (
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: November 5, 2007 ITEMNO.6B
( continued)
Annada Drive follows a curvilinear alignment and has roadway grades that vary between
1.0% to 8.0%. The steepest portion of the road is northerly of Palomar Airport Road.
Based upon traffic counts obtained in August 2007, two-way total traffic volumes on
Annada Drive range from 4,136 vehicles per day south of the northerly Fleet Street
intersection to 8,280 vehicles per day northerly of Palomar Airport Road. The directional
distribution of traffic volumes on Annada Drive is indicated in Table A.
TABLE A
24-HOUR TRAFFIC VOLUMES
ARMADA DRIVE
24-HOURADT
DATE LOCATION. S/B TOTAL
8/08/07 4,315 8,280
8/28/07 South of Fleet Street 1,959 2,177 4,136
There have been three reported collisions in the two-year period ending May 31, 2007.
Two of the three collisions were speed-related. However, the roadway collision rate for
Annada Drive is 0.76 accidents per million vehicle miles, which is less than one-half of the
statewide collision rate of 1.90, based upon a comparable roadway.
The 85 th 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: November 5, 2007
( 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 Armada Drive from
Palomar Airport Road to LEGO LAND Drive. Results of two speed surveys, contained within
the Engineering and T~affic Survey prepared for Armada Drive, are summarized in Table B.
TABLEB
SPEED SURVEY DATA FOR ARMADA DRIVE
0.23 miles n/o Palomar Ai
0.20 miles s/o Fleet Street
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 40 mile per hour prima facie speed limit upon Armada
Drive from Palomar Airport Road to LEGOLAND Drive.
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 Annada Drive, as recommended.
PROPOSED
SPEED ZONE
NOT TO SCALE
PROJECT NAME
LOCATION
____ "s
r=-c---CANNONRD.
(
MAP
LEGEND:
@ TRAFFIC SIGNAL ==:I DRIVEWAY
PROPOSED SPEED ZONE FOR
ARMADA DRIVE
EXHIBIT
1
DRA'MI BY: SCOTT EVANS, CARLSBAD ENGINEERING DEPT. 9 11 07 C: 1RAmc SPEEO ZONES SPEED ZONE-ARMADA2.DWG
( CITY OF CARLSBAD (
Et+..~INEERING AND TRAFFIC SUKVEY
STREET: Armada Drive
LIMITS: Palomar Airport Road to LEGOLAND Drive
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:
(6/01/05 through 5/31/07)
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
8/23/07
0.23 Mi. n/o Palomar Airport Road
41 MPH
33 to 43 MPH
83%
35 MPH
2
3
0.76
Direction: Northbound/Southbound
8/30/07
0.2 Mi. s/o Fleet Street (North)
45MPH
36 to 46 MPH
81%
35 MPH
1.90 (2005 Rate for 4 or More Divided Lanes)
8,280 -North of Palomar Airport Road (8/08/07); 4,136 -South of Fleet Street (N) (8/28/07)
Traffic Signal at Palomar Airport Road; Roundabout at LEGOLAND Drive
Moderate
Bicycle Lane on Each Side Except Northerly 400 Feet of East Side
Parking Allowed only on West Side in Designated Spaces
Bus Route; Bus Turnouts Exist on Each Side
Not Classified
0.87 Mi.
68 Feet to 72 Feet
2 Lanes Each Direction
Roadway Grades Vary from 1% to 8%
Curvilinear
Sidewalk on Each Side
Nine Driveways
Street Lights on Each Side
E. Special Conditions: Travel lanes are separated by either a two-way left-turn lane or a raised, landscaped median.
Southbound travel lanes are reduced to one throu h-lane and one ri ht-turn-on! lane at Palomar Air ort Road.
F. Adjacent Land Uses: Light Industrial/Manufacturing, Agricultural, LEGOLAND Theme Park, Resort/Restaurant, Museum,
Scenic Overlook
G. Remarks/Conditions Not Readily Apparent: Armada Drive serves as a connection between Cannon Road on the north, which is
a major arterial, and Palomar Airport Road, which is a prime arterial. Northbound motorists approaching LEGOLAND Drive are
advised · of a roundabout at the intersection through a series of curve warning signs and 15 MPH speed advisory plates.
Pedestrians cross Armada Drive at various midblock locations to access the sidewalk/scenic overlook on the west side of the
roadway and a pedestrian access gate to LEGOLAND on the east side of the roadway. Pedestrians also cross the roadway using
four marked crosswalks at the intersections of Fleet Street N and Fleet Street S .
H. Traffic Engineer's Recommendation (Explanation): This speed zone satisfies the conditions of Section 627 of ttie 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 of40 MPH is found to be appropriate
and ·ustified. ~=,,.......,....,..
DATE: 08/23/07 TIME: 10:05 AM TO
CITY OF CARLSBAD(
SPEED SURVEY
10:40 AM TOTAL VEHICLES:
WEATHER: Clear & Warm CRITICAL SPEED:
LOCATION: Armada Drive -.23 mi. n/o Palomar Airport Road VEHICLES IN PACE:
OBSERVER/RECORDER: M. Rehfeldt ---------PACE SPEED(S):
35 MPH
POSTED SPEED LIMIT
SOUTHBOUND
DIRECTION OF TRAVEL
MPH # % l: # % %tile % #
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46 X
45 X X
44 X X
43 X X
42 X X X
41
40 X X X
39 X X X X X
38 X X X X X X
37 X X X X X X X
36 X X X X X
35 X X X X X
34 X X X X
33 . X X X X
32 X
31
30
29
28
27
26
25
24
23
22
21
1 2 1 1 100
2 4 2 2 99
2 4 2 2 97
2 4 3 3 95 2 1
3 6 6 6 92 6 3
3 3 86 6 3
3 6 7 7 83 8 4
5 10 10 10 76 10 5
6 12 9 9 66 6 3
7 14 12 12 57 10 5
5 10 8 8 45 6 3
5 10 9 9 37 8 4
4 8 10 10 28 12 6
4 8 9 9 18 10 5
1 2 5 5 9 8 4
1 1 4 2 1
2 2 3 4 2
1 1 1 2 1
Engineering Department
Transportation Division
100
41 MPH ------'-'------
83 % -----------
33 TO 43 MPH
NORTHBOUND
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
X 43
X X X 42
X X X 41
X X X X 40
X X X X X 39
X X X 38
X X X X X 37
X X X 36
X X X X 35
X X X X X X 34
X X X X X 33
X X X X 32
X 31
X X 30
X 29
28
27
26
25
24
23
22
21
---------------:{ \
DATE: • 8/30/07 TIME: 10:15 AM TO
CITY OF CARLSBAD ,
SPEED SURVEY
11:00AM TOTAL VEHICLES:
WEATHER: _S_u_n~ny~&_H_o_t _________ _ CRITICAL SPEED:
LOCATION: Armada Drive-0.2 mi. s/o Fleet Street (N) VEHICLES IN PACE:
OBSERVER/RECORDER: J. Gale ---------PACE SPEED(S):
35 MPH
POSTED SPEED LIMIT
NORTHBOUND
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 X
46 X
45 X X X X
44 X X X X X
43 X X X X X X
42 X X
41 X X X X X X
40· X X X X X X X
39 X X X X X X
38 X X
37 X X X X X
36 X X
35 X X
34
33 X
32
31
30
29
28
27
26
25
24
23
22
21
1 1 100 2 1
1 1 99 2 1
1 2 2 2 98 2 1
1 2 4 4 96 6 3
4 8 9 9 92 10 5
5 10 6 6 83 2 1
6 12 10 10 77 8 4
2 4 6 6 67 8 4
6 12 11 11 61 10 5
7. 14 9 9 50 4 2
6 12 9 9 41 6 3
2 4 5 5 32 6 3
5 10 11 11 27 12 6
2 4 5 5 16 6 3
2 4 6 6 11 8 4
1 1 5 2 1
1 2 3 3 4 4 2
1 1 1 2 1
Engineering Department
Transportation Division
100
45 MPH -----------
81 % -----------
36 TO 46 MPH ----------
SOUTHBOUND
DIRECTION OF TRAVEL
MPH
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
X 49
X 48
X 47
X X X 46
X X X X X 45
X 44
X X X X 43
X X X X 42
X X X X X 41
X X 40
X X X 39
X X X 38
X X X X X X 37
X X X 36
X X X X 35
X 34
X X 33
X 32
31
30
29
28
27
26
25
24
23
22
21