HomeMy WebLinkAbout2006-10-02; Traffic Safety Commission; ; Establish a prima facie speed limit upon Rancho Santa Fe Road from La Costa A venue to the north City limit{
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CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: October 2, 2006 ITEMNO.6B
LOCATION: Rancho Santa Fe Road, La Costa A venue to the north City limit
INITIATED BY: Traffic Division, Carlsbad Police Department
REQUESTED ACTION: Establish a prima facie speed limit upon Rancho Santa Fe Road from
La Costa A venue to the north City limit
BACKGROUND:
Construction of Rancho Santa Fe Road from La Costa Avenue to Melrose Drive that has
taken place over the past three years has recently been completed. The road was widened
to a six lane, divided road with intersection improvements, including the installation of
traffic signals. Minor punchlist items remain to be completed.
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.
C (
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: October 2, 2006
(continued)
ITEMNO. 6B
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. 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 (85th percentile speed)
2. Collision history
3. Conditions that may not be readily apparent to the driver
The premise implied in sfeed zoning is that the majority of drivers are operating their
vehicles at or near the 851 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
85 th 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.
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 turn, is considered when establishing a prima facie speed limit.
( (
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: October 2, 2006
(continued)
ITEMNO. 6B
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:
Rancho Santa Fe Road is classified as a prime arterial in the Circulation Element of the
General Plan. Prior to the recent completion of widening Rancho Santa Fe Road (RSF)
between La Costa A venue and the north City limit, RSF was essentially a two-lane road
constructed an unknown number of years in the past. The road did not meet current
standards for a prime arterial and it was upgraded to a six-lane roadway having three
traffic lanes in each direction separated by a raised, landscaped median. Curb and gutter,
sidewalks, street lights, and bicycle lanes were built to City standards, although a portion
of the road has future sidewalk and street light locations to be constructed as an
obligation of pending development.
Improvements to the Melrose Drive intersection were part of the road widening project,
including moving this intersection about 400 feet northerly into San Marcos from its
former location. The new Melrose Drive/Rancho Santa Fe Road intersection is under the
jurisdiction and control of the City of San Marcos. Carlsbad's north city limit line
intersects Rancho Santa Fe Road about 400 feet southerly of Melrose Drive.
( (
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: October 2, 2006 ITEMNO. 6B
( continued)
A number of funding sources were used to pay for the construction of Rancho Santa Fe
Road, including private funds as the road was constructed in conjunction with a large
housing development called The Villages of La Costa. Consequently, three new
signalized intersections were installed to serve the housing development and upgrades to
the intersections at La Costa A venue, San Elijo Road, and Melrose Drive were made.
Each intersection has left-tum lanes on Rancho Santa Fe Road served by an exclusive
left-tum arrow. The curb-to-curb width varies along Rancho Santa Fe Road between
102 feet and 112 feet. Centerline grades vary along the road from 1.74 to 5.62 percent.
Traffic counts were obtained on Rancho Santa Fe Road on August 29, 2006 to measure
the two-way, 24-hour daily traffic volume. The recent count data is indicated on Table A.
The Carlsbad ADT design range for a prime arterial is in excess of 40,000 vehicles per
day.
Date
8/29/06
8/29/06
TABLE A
24-HOUR TRAFFIC VOLUMES
RANCHO SANTA FE ROAD
24-Hour ADT _ .
Location NB SB Total
North of San Eliio Road 14,799 16,541 31,340 _.,_---,-------+---~....,...,,...,,-----1----,--,-~------,-~--,------i NorthofLaCostaAvenue 18,690 19,577 38,267
Staff conducted three speed surveys on Rancho Santa Fe Road on August 22, 2006
to obtain data to calculate the critical speed of vehicles. The critical speed, commonly
called the 85th percentile speed, is the free flowing speed at which 85 percent of the
vehicles are traveling at or below. A sample of 100 vehicles was measured to calculate
the critical speed. The critical speed is an important factor required to be considered in
the evaluation for determining the appropriate prima facie speed to post upon a roadway.
The 85th percentile speed has been determined throughout the United States to generally
conform to a safe and reasonable speed limit. The 2003 Manual on Uniform Traffic
Control Devices (MUTCD) California Supplement 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.
( (
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: October 2, 2006
(continued)
ITEMNO. 6B
(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;
(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 Rancho Santa Fe Road
between La Costa Avenue and the north City limit. Results of the speed survey, contained
within the Engineering and Traffic Survey that was conducted on Rancho Santa Fe Road,
are summarized in Table B.
TABLED
SPEED SURVEY DATA FOR RANCHO SANTA FE ROAD
8/22/06 450 feet north of San Elijo Road NB/SB
8/22/06 0.4 mile north of Camino Junipero NB/SB
8/22/06 at Paseo Lupino NB/SB
58
59
58
48-58
49-59
50-60
49-59
75
80
77
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.
( (
CITY OF CARLSBAD
TRAFFIC SAFETY COMMISSION
STAFF REPORT
COMMISSION MEETING OF: October 2, 2006
( continued)
ITEMNO. 6B
The expansion of Rancho Santa Fe Road to six lanes and the resulting free-flow
conditions generates high critical speeds. In accordance with MUTCD criteria and the
prevailing critical speeds, a prima facie speed limit of 60 miles per hour could be
considered. However, the number of intersections, bicycle lanes on Rancho Santa Fe
Road, nearby residential development, future commercial development, and driveways
that intersect Rancho Santa Fe Road, all suggest an appropriate prima facie speed limit
for the roadway of 55 miles per hour.
RECOMMENDATION:
Upon review of the results of the Engineering and Traffic Survey, the Traffic Safety
Coordinating Committee recommends establishing a 55 mile per hour prima facie speed
limit upon Rancho Santa Fe Road from La Costa A venue to the north City limit.
NECESSARY CITY COUNCIL ACTION:
An ordinance will be required to be adopted by the City Council to establish the 55 mile
per hour prima facie speed limit upon Rancho Santa Fe Road, as recommended.
I
LOCATION MAP
PROPOSED
SPEED ZONE
l
PROJECT NAME PROPOSED SPEED ZONE
RANCHO SANTA FE ROAD
DRAl'rN BY: SCOTT EVANS, CARLSBAD ENGINEERING DEPT. 9/11/06 C: TRAFFIC SPEED ZONE SPEED ZONE-RANCHO SANTA FE ROAD2.DWG
NELJJORD.
NOT TO SCALE
EXHIBIT
1
( CITY OF CARLSBAD
ENGINEERING AND TRAFFIC SURVEY
(
STREET: Rancho Santa Fe Road
LIMITS: North City Limit to La Costa Avenue
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:
(8/01/04 through 7/31/06)
Speed-Related Accidents
Total Accidents
Direction:
Northbound/Southbound
8/22/06
450 feet n/o San Elijo Road
58 MPH •
48 to 58 MPH
75%
No Posted S eed Limit
16
Direction:
Northbound/Southbound
8/22/06
0.4 mi. n/o Camino Junipero
59MPH
49 to 59, 50 to 60 MPH
80%
No Posted S eed Limit
Direction:
Northbound/Southbound
8/22/06
At Paseo Lupino
58MPH
49 to 59 MPH
77%
No Posted S eed Limit
Accidents/Million Vehicle Miles (MVM)
California Statewide Accidents/MVM
30 (Including 10 Collisions in the Construction Zone)
0.54
2.03 (2004 Rate for Same Type of Roadway)
C. Traffic Factors:
Average Daily Traffic
Traffic Controls
Pedestrian/Bicycle Traffic
Bicycle Lanes
On-Street Parking
Other
D. Roadway Factors:
Street Classification
Length of Segment
Roadway Width
Number of Lanes
Vertical Alignment
Horizontal Alignment
Sidewalks
Driveways
Street Li htin
31,340-North of San Elijo Road (8/29/06); 38,267 -North of La Costa Avenue (8/29/06)
Traffic Signals at San Elijo Rd, Avenida Soledad, Camino Junipero, Paseo Lupino & La Costa Ave
Low
Bicycle Lane on Each Side
Parking Prohibited on Each Side
Bus Route; Truck Route; Bike Route per Circulation Element of the General Plan
Prime Arterial
2.18 mi.
Roadway Width Varies between 102 Feet and 112 Feet (Curb-to-Curb)
Three Lanes Each Direction
Roadway Grades Vary from 1. 7 4% to 5.615%
Curvilinear
Sidewalk on Each Side Except 800 Feet on West Side and 3,300 Feet on East Side
Five Driveways
Street Lights on Each Side Except from Paseo Lupino to a Point 1,850 Feet North on East Side
E. Special Conditions: Rancho Santa Fe Road serves as a regional connection between La Costa Avenue and Melrose Drive.
Travel lanes are separated by a raised median, most of which is landscaped. The roadway is used by regional commuters and
local residents. Police motorcycle officers utilize depressions at midblock locations in the raised median for U-turns. Several bus
turnouts are provided throughout the segment. Right-turn-only lanes exist at the intersection of Paseo Lupino, Camino Junipero,
Avenida Soledad, San Eli'o Road and La Costa Meadows Drive.
F. Adjacent Land Uses: Water Reclamation Facility, Industrial/Business Park including Light Commercial, Single-Family and
Multi-Family Residential, Open Space; Creek, Bus Stops, RV Storage, Future Fim Station, FutUie Affordable Housing
Develo ment, and Future Ma·or Sho in Center.
G. Remarks/Conditions Not Readily Apparent: Construction vehicles enter and exit the existing roadway at various locations due
to ongoing construction activity. A truck crossing is established at Avenida Soledad. The west leg of the intersection at San Elijo
Road and both legs of the intersection at Avenida Soledad are currently under construction. Seven of the 16 speed-related
collisions occurred in a construction zone and four of the speed-related collisions occurred during rainy conditions. One-third of
the total collisions occurred in a construction zone.
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 Manual on Uniform Traffic Control Devices (MUTCD)
2003 Edition as amended by the MUTCD 2003 California Supplement with respect to design and prevailing speeds, accident
records, pedestrian and bicyclist safety, intersection and driveway spacing, and roadside and traffic conditions not readily
a arent to the driver. A s eed limit ostin of 55 MPH is found to be a ro riate and ·ustified.
(
DATE: 8/22/06 TIME: 3:00 PM TO
(
CITY OF CARLSBAD
SPEED SURVEY
3:25 PM TOTAL VEHICLES:
WEATHER: Sunny & Mild CRITICAL SPEED:
LOCATION: Rancho Santa Fe Rd.~450' n/o San Elijo Rd. VEHICLES IN PACE:
OBSERVER/RECORDER: • J. Gale PACE SPEED(S): ---------
NONE
POSTED SPEED LIMIT
SOUTHBOUND
DIRECTION OF TRAVEL
MPH # % l: # % %tile % #
65
64
63
62 X
61
60 X
59 X
58
57 X X
56 X X X X
55 X
54 X X X X
53 X X X X X X X
52 X X X X X X
51 X X
50 X X X X X
49 X
48 X X
47 X
46
45
44
43
42
41
40
39 ...
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
1 2 1 1 100
3 6 3 3 99
2 4 3 3 96 2 1
3 6 4 4 93 2 1
3 6 4 4 89 2 1
1 2 3 3 85 4 2
3 6 3 3 82
5 10 9 9 79 8 4
1 2 8 8 70 14 7
4 8 10 10 62 12 6
7 14 14 14 52 14 7
6 12 9 9 38 6 3
2 4 7 7 29 10 5
5 10 7 7 22 4 2
1 2 3 3 15 4 2
2 4 5 5 12 6 3
1 2 2 2 7 2 1
1 1 5 2 1
3 3 4 6 3
1 1 1 2 1
'
Engineering Department
Transportation Division
100
58 MPH --------'------
75 % --------'------
48 TO 58 MPH -----
NORTHBOUND
DIRECTION OF TRAVEL
MPH
65
( 64
63
62
61
60
59
X 58
57
X X X X 56
X X X X X X X 55
X X X X X X 54
X X X X X X X 53
X X X 52
X X X X X 51
X X 50
X X 49
X X X 48
X 47
X 46
X X X 45
X 44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
DATE: 8/22/06 TIME: 1:40 PM TO
WEATHER: Sunny & Warm
CITY OF CARLSBAD
SPEED SURVEY
2:20 PM TOTAL VEHICLES:
CRITICAL SPEED:
LOCATION: Rancho Santa Fe Rd.~0.4 mi. n/o Camino Junipero VEHICLES IN PACE:
OBSERVER/RECORDER: J. Gale ----------PACE SPEED(S):
NONE
POSTED SPEED LIMIT
SOUTHBOUND
DIRECTION OF TRAVEL
MPH # % I:# % %tile % #
65
64
63
62
61
60
59
58 X
57 X X
56
55 X X X X X X X
54 X X X X X
53 X X X X X
52 X
51 X X X X
50 X X X
49 X X
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
1 2 1 1 100
1 2 1 1 99
2 4 3 3 98 2 1
2 4 4 4 95 4 2
2 4 5 5 91 6 3
3 6 5 5 86 4 2
4 8 5 5 81 2 1
5 10 10 10 76 10 5
3 6 8 8 66 10 5
7 14 13 13 58 12 6
5 10 8 8 45 6 3
5 10 9 9 37 8 4
1 2 4 4 28 6 3
4 8 8 8 24 8 4
3 6 5 5 16 4 2
2 4 5 5 11 6 3
4 4 6 8 4
1 1 2 2 1
1 1 1 2 1
--
Engineering Department
Transportation Division
100
____ ___;5~9:___ ____ MPH
80 % -----------
49 TO 59 MPH ----'--------
50 TO 60 MPH ----------
NORTHBOUND
DIRECTION OF TRAVEL
MPH
65
64
63
62
X 61
X X 60
X 59
58
X X X X 57
X X X X 56·
X X X X X X 55
X X X 54
X X X X 53
X X X 52
X X X X 51
X X 50
X X X 49
X X X X 48
X 47
X 46
45
44
43
42
41
40
3S
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
DATE: 8/22/06 TIME: 2:30 PM
WEATHER: Sunny & Warm
CITY OF CARLSBAD
SPEED SURVEY
(
TO 2:55 PM TOTAL VEHICLES:
CRITICAL SPEED:
LOCATION: Rancho Santa Fe Road at Paseo Lupino VEHICLES IN PACE:
OBSERVER/RECORDER: J. Gale PACE SPEED(S): ---------
NONE
POSTED SPEED LIMIT
SOUTHBOUND
DIRECTION OF TRAVEL
MPH # % E # % %tile % #
65
64
63
62
61
60
59
58
57 X
56 X X
55 X
54 X X X X
53 X X X X X
52 X X X X X
51 X X X X X
50 X X X X
49 X X
48
47
46
45
44
43
42
41
40
39 --.
38
37
36
35
34
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 2 2 97
2 4 3 3 95 2 1
3 6 3 3 92
3 6 7 7 89 8 4
4 8 7 7 82 6 3
5 10 6 6 75 2 1
2 4 6 6 69 8 4
5 10 13 13 63 16 8
5 10 10 10 50 10 5
5 10 10 10 40 10 5
5 10 6 6 30 2 1
4 8 6 6 24 4 2
2 4 6 6 18 8 4
4 4 12 8 4
3 3 8 6 3
2 2 5 4 2
2 2 3 4 2
1 1 1 2 1
Engineering Department
Transportation Division
-.
100
58 MPH
77 % -----------
49 TO 59 MPH
NORTHBOUND
DIRECTION OF TRAVEL
MPH
65
64
63
62
61
X 60
59
X X X X 58
X X X 57
X 56
X X X X 55
X X X X X X X X 54
X X X X X 53
X X X X X 52
X 51
X X 50
X X X X 49
X X X X 48
X X X 47
X X 46
X X 45
X 44
43
42
41
40
• ·39·
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21