HomeMy WebLinkAbout1986-09-08; Traffic Safety Commission; ; Intersection of Alga and Corintia, Alga and El Fuerte, and El Fuerte and CorintiaCIT•¥ OF CARLSBAD
TRAFFIC SAFETY COMMISSION
COMMISSION REPORT OF: September 8, 1986 ITEM NO.D-2
LOCATION: Intersection of Alga and Corintia, Alga and El
Fuerte, and El Fuerte and Corintia.
INITIATED BY: Frederic Wise, Principal, La Costa Meadows
School
PROBLEM AS STATED BY REQUESTOR:
his concern about
He believes that
the safety of
Mr. Wise has sent a letter expressing
several issues (see attached letter),
implementing his suggestions will improve
children attending the new elementary school,
BACKGROUND:
The following items are discussed in the same order as presented
in the letter by Mr. Wise.
1. Stop sign on El Fuerte at Corintia.
El Fuerte was recommended as a Through Street by the Traffic
Safety Commission in May 1986, allowing stop signs to be
installed on intersecting streets. The City Council approved
the Through Street designation and a work order has been sent
to Utilities and Maintenance for installation of a stop sign
on Corintia.
El Fuerte Street has an A.D.T. of 342 vehicles at the school
site with no accidents having been reported at the El Fuerte
and Corinitia intersection since 1977. A speed survey was
conducted on August 14, 1986, with the critical speed found
to be 42 miies per hour. At this location, stop sign
warrants are not met. In the future as Corintia is extended
easterly, conditions will change. Staff will continue to
monitor this intersection.
Sight distance at the top of the crest
front of the school when approaching
southbound is approximately 350 feet, which
vertical curve in
Corintia Street
provides stopping
TRAFFIC SAFETY COMMISSION
COMMISSION REPORT DF: September 8, 1986
Continued
ITEM NO.D-2
sight distance on wet pavement for a vehicle traveling
approximately 45 miles per hour. Northbound traffic on El
Fuerte approaching Corintia has sight distance of
approximately 400 feet, which would provide stopping sight
distance on wet pavement for a vehicle traveling
approximately 50 miles per hour.
Alga Road west of the Corintia Street intersection has a
critical speed of 52 miles per hour and therefor would be
considered a rural location for purposes of evaluating
traffic signal warrants. Warrants are attached on Exhibit 1,
obtained from the Caltrans Traffic Manual. As stated in the
Traffic Manual, a traffic signal should be considered if one
or more warrants are met.
Traffic count volumes are attached (see Exhibit 2). Volumes
do not meet the warrants for a traffic signal. In the past
12 months there have been two (2) reported traffic accidents
at the intersection, which also does not meet signal
warrants. A review of other warrants indicates that a signal
cannot be recommended at this time due to warrants not being
met.
The southeast corner of Alga and El Fuerte has not been
constructed to the full pavement width with curb and gutter
and sidewalk. This causes a "jog" in the roadway, which is a
hazard. Crosswalks could not be efficiently painted on the
southeast corner. A preconstruction meeting was held August
28, 1986 to discuss the widening of Alga from El Fuerte
easterly, Within three (3) months, the curb and gutter and
pavement is expected to be installed on the southeast corner
of the intersection, At the time the improvements are
completed at the intersection, a crosswalk will be painted on
the south and east legs of the intersection.
Students should be encouraged to walk on the sidewalk located
on the west side of El Fuerte Street. Bike riders should be
trained in the safety aspects of riding a bike on public
streets and made aware of their responsibilities. The Police
Department has a program for bike safety that will be
presented to the students at each school in Carlsbad,
including La Costa Meadows School.
TRAFFIC SAFETY COMMISSION
COMMISSION REPORT Of: September B, 1986
Continued
RECOMMENDATION:
ITEM NO.D-2
Stop signs and traffic signal warrants are not met at this
time and those devices cannot be recommended for installa-
tion. A crosswalk should not be painted until the southeast
corner of Alga and El Fuerte Street improvements have been
completed.
NECESSARY COUNCIL ACTION:
An ordinance will be required for Council action if stop
signs are recommended. A traffic signal would need to be
approved by Council if one is recommended.
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Ia Costa Meadovv., Schoo(
6889 E( Fuerte St.
Carfs&ad", CA 92008
San Marros Unified" Schoo[ District
August 7, 1986
Mr. Robert T. Johnson, Jr.
Traffic Engineer, Carlsbad
2075 Las Palmas Drive
Carlsbad, CA 92008
Dear Mr. Johnson:
' ) .. ~-;; -~~.;~;~~~_·t~. ; i''~~) . . ..
--.•--~----·
Following our conversation and agreements today, I .am writing to confirm
my continuing concern for the follow,ing i.tems. Please add these to your
agenda for consideration by the Traffic Safety Coordinating Committee.
1. Stop sign on El Fuerte, at Corintia.
Rationale: fast traffic; park use at non-school times.;
limited visibility both south and northbound
on El Fuerte; need for students walking and
bi·king to cross El Fuerte.
2. Signal on Alga at Corintia.
Rationale: students and parents have indicated that is
the preferred route for walkers, bike riders,
both to school and the park; high speeds on
Alga; large numbers of students across (north
of) Alga.
3. Crosswalks at all four corners of Alga and El Fuerte. (You
have indicated you already plan to insta.11 crosswalks on both
the north and west legs at that intersection).
Rationale: Bike riders need a designated area to walk bikes
across the street; students walking against traffic,
south on El .Fuerte, must cross the east side of
El Fuerte; crossing guard needs an area to direct
students to stay within, i.e. a crosswalk.
Thank you for your attention to these matters, and for placing these items
on the September 8 Traffic Commission meeting. Members of the La Costa
Meadows Parent-Teacher Organization Executive Board plan to attend that
meeting.
Very truly yours,
L~EADO~S SCHOOL
~~--£-Frederic J. Wise
Principal
Traffic Manual TRAFFIC SIGNALS AND LIGHTING &-1
12-1979
CHAPTER 9
TRAFFIC SIGNALS AND LIGHTING
Traffic Signals-Basic Information and Warrants 9~1
9-41.1 lntrodudion
Traffic signals are electrically powered traffic con-
trol devices which alternately direct traffic to stop
and proceed at highway and street intersections.
Their purpose is the orderly assignment of right of
way to the various traffic movements.
When justified and properly designed, a traffic sig-
nal installation may achieve one or more of the fol-
lowing:
l. Reduce the frequency of certain types of acci-
dents; especially the right-angle type;
2. Effect orderly traffic movement;
3. By proper coordination, the continuous flow of
a platoon of traffic at a definite speed along a
given route;
4. Allow other vehicles and pedestrians to cross a
heavy traffic stream; and
5. Control traffic more economically than by man-
ual methods.
Unjustified, ill-designed, improperly-operated, or
poorly maintained traffic signals may cause:
l. Increased accident frequency,
2. Excessive delay,
3. Disregard of signal indications, and
4. Circuitous travel by alternate routes.
Contrary to common belief, traffic signals do not
always increase safety and reduce delay. Experience
shows that the number of right-angle collisions may
decrease after the installation of signals, but the num-
ber of rear-end collisions will increase in many in-
stances. The installation of signals may increase over-
all delay and reduce intersection capacity.
Consequently, it is of the utmost importance that the
consideration of a signal installation and the selection
of equipment be preceded by a thorough study of
traffic and roadway conditions made by an engineer
experienced and trained in this field. Equally impor-
tant is the need for checking the efficiency of a traffic
signal in operation. This determines the degree to
which the type of installation and the timing pro-
gram meets the requirements of traffic.
9-41.2 Warrants
The warrants for the installation of traffic signals
are based on those stated in the Manual on Uniform
Traffic Control Devices. These warrants apply to
both pre-timed and traffic-actuated traffic signals.
When the 85--percentile speed of major street traf-
fic exceeds 40 miles per hour, or when the intersec-
tion lies within the built-up area oi an isolated com-
munity having a population less than 10,000, the
location is considered rural. All other· areas are con-
sidered urban. Since the installation of traffic signals
may increase certain types of collisions, the decision
to install signals should not be based solely upon war-
rants. Consideration should also be given to such fac-
tors as delay, congestion, approach conditions, driver
confusion and additional evidence of need for right
of way assignment above that which could be pro-
vided by stop signs.
The installation of traffic signals should be consid-
ered if one or more of the warrants listed below are
met:
Warrant 1-Minimum Vehicular Volume.
Warrant 2 -Interruption of Continuous Traffic.
Warrant 3 -Minimum Pedestrian Volume.
Warrant 4 -School Crossings.
Warrant 5 -Progressive Movement.
Warrant 6 -Accident Experience.
Warrant 7 -Systems.
Warrant 8-Combination of Warrants.
9--'11.3 Warrant 1 -Minimum Vehicular Volume
The minimum vehicular volume warrant is intend-
ed for application where the volume of intersecting
traffic is the principal reason for consideration of sig-
nal installation. The warrant is satisfied when for
each of any 8 hours of an average day the traffic
volumes given in the table below exist on the major
street and on the higher-volume minor street ap-
proach to the intersection.
Number or lanes for
moving traffic on
each approach
Vehicles per
hour on major
street (total
of both
approaches)
Vehicles per
hour on higher-
volume minor-
street approach
Cone direction
only)
(Minimum Requirements)
Major Street Minor Street Urban Rural Urban Rural
1---···· 1 ....... 500 j50 150 105
2 or more --1---···-600 420 150 105
2 or more --2 or more .... 600 420 200 140
1-----·-2 or more --500 350 200 140
S-rlT. J
9-2 TRAFFIC SIGNALS AND LIGHTING Traffic Manual
12-1979
The major street and the minor street volumes are
for the same 8 hours. During those 8 hours the direc-
tion of higher volume on the .minor street may be on
one approach during some hours and on the opposite
approach during other hours.
Left tum movements from the major street may
be included with minor street volumes if a separate
signal phase is to be provided for the left tum move-
ment. The left tum volume in the highest direction
may be added to the minor street volume on the
highest approach and the major street volume should
be reduced by this amount.
9-41.4 Warrant 2-lnterruptlon of Continuous Traffic
The interruption of continuous traffic warrant ap-
plies to operating conditions where the traffic vol-
ume on a major street is so heavy that traffic on a
minor intersecting street suffers excessive delay or
hazard in entering or crossing the major street. The
warrant is satisfied when for each of any 8 hours of
an average day the traffic volumes given in the table
below exist on the major street and on the higher-
volume minor street approach to the intersection,
and the signal installation will not seriously disrupt
progressive traffic flow.
Number or lanes ror
moving traffic on
each approach
Vehicles per
hour on major
street (total
of both
approaches)
Vehicles per
hour on higher-
volume minor•
street approach
<one direction
only)
(Minimum Requirements)
Major Street Minor Street 1l!2!!L ~ ll!l?!D ~
1------~ 1-------750 525 75 53
2 or more ..... 1-------900 630 75 53
2 or more .... 2 or more-• 900 630 100 70
1-------2 or more .... 750 525 100 70
The major street and minor street volumes are for
the same 8 hoUrs. During those 8 hours the direction
of higher volume on the minor street may be on one
approach during some hours and on the opposite
approach during other hours.
Left tum movements from the major street may
be included with minor street volumes if a separate
signal phase is to be provided for left tum move-
ment. The left tum volume in the highest direction
may be added to the minor street volume on the
highest approach and the major street volume should
be reduced by this amount.
9-41.5 Waffllnt 3-Minimum Pacle1trlan Volume
The minimum pedestrian volume warrant is satis-
fied when for each of any 8 hours of an average day
the following traffic volumes exist:
1. On the major street 600-Urban, 420-Rural or
more vehicles per hour enter the intersection
(total of both approaches): or 1,000-Urban, 700
-Rural or more vehicles per hour (total of both
approaches) enter the intersection on the ma-
jor street where there is a raised median island
four feet or more in width; and
2. During the same 8 hours as in paragraph I.,
there are 150-Urban, !OS-Rural or more pede-
strians per hour on the highest volume cross-
walk crossing the major street.
A signal installed under this warrant at an isolated
intersection should be of the traffic-actuated type
with push buttons for pedestrians crossing the main
street. If such a signal is installed at an intersection
within a signal system, it should be equipped and
operated to provide proper coordination.
Signals installed according to this warrant shall be
equipped with pedestrian indications conforming to
requirements set forth in other sections of this Man-
ual.
Signals may be installed at nonintersection loca-
tions (Mid-block) provided the requirements of this
warrant are met, and provided that the related cross-
walk is not closer than 150 feet to another established
crosswalk. Curbside parking should be prohibited for
a minimum of 100 feet· in advance of and 20 feet
beyond the crosswalk. Phasing, coordination and in-
stallation must conform to standards set forth in this
Manual. Special attention should be given to the sig-
nal head placement and the signs and markings used
at nonintersection locations to be sure drivers are
aware of this special application.
9-41.6 Waffllnt 4-Schaal Cra11ing1
See Chapter 10.
9-41.7 Warrant 5 -PN19ra11lve Movement
The progressive movement warrant is satisfied
when one of the following is true:
1. On a one-way street or on a street which pre-
ponderantly has unidirectional traffic signifi-
cance, adjacent signals are so far apart that the
necessary degree of platooning and speed con-
trol of vehicles would otherwise be lost or,
2. On a two-way street, where adjacent signals do
not provide the necessary degree of platooning
and speed control and the proposed and adja-
cent signals could constitute a progressive signal
system.
The installation of a signal according to this war-
rant should be based on the BS-percentile speed un-
less an engineering study indicates that another
speed is more desirable.
The installation of a signal according to this war-
FXH1AIT I ~rl-1. /_
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Traffic Manual TRAFFIC SIGNALS AND LIGHTING 9-:
rant should not be considered where the resultant
signal spacing would be. Jess than 1,000 feet.
9-41.8 Warrant 6-Accident Experience
The accident-experience warrant is satisfied
when:
1. Adequate trial of less restrictive remedies with
satisfactory observance and enforcement has
failed to reduce the accident frequency; and
2. Five or more reported accidents of types sus-
ceptible of correction by traffic signal control
have occurred within a 12-month period, each
accident. involving personal.injury or property
damage to an apparent extent of $200 or more;
and
3. There exists a volume of vehicular and pedes-
trian traffic not less than 80 percent of the re-
quirements specified in the minimum vehicular
-volume warrant, the interruption of continu-
ous traffic warrant, or the minimum pedestri!lD
-volume warrant; and
4. The signal installation will not seriously disrupt
progressive traffic flow.
9-41.9 Warrant 7 -Systems Warrant
A traffic signal installation at some intersections
may be warranted to encourage concentration and
organization of traffic flow networks. The systems
warrant is applicable when the common intersection
of two or more major routes has a total existing, or
immediately projected, entering volume of at least
800 vehicles during the peak hour of a typical week-
12-19~
day, or each of any five hours of a Saturday and101
Sunday. '
A major route as used in the above warrant has om
or more of the following characteristics:
I. It is part of the street or highway system tha
serves as the principal network for through traf
fie flow;
2. It connects areas of principal traffic generation
3. It includes rural or suburban highways outsid,
of, entering or traversing a city;
4. It has surface street freeway or expresswai
ramp' terminals;
5. It appears as a major route on an official plar
such as a major street plan in an urban are,
traffic and transportation study.
9-41,10 Warrant I-Combination of Warrants
In exceptional cases, signals occasionally may b,
justified where no single warrant is satisfied bu
where any two of Warrants I, 2 and 3 are satisfied t,
the extent of 80 percent or more of the stated numer
ical values for each of any 8 hours of an average day
9-41.11 Periodic Traffic Signal Studies
To maintain the desirable operation· of existiJI!
traffic signals it is necessary to periodically conduc
engineering ;tudies to ensure that the desired opera
tion is realized. In particular, engineering studie,
should determine whether the installation continue,
to be justified and that the signal timing in use meet,
the current traffic requirements.
TRAFFIC COUNT DATA SHEET
TS# __ _
Street(s).
Count Date S-) 3'·5::'.to B~l.!/-6(.. Data Reduction by /'-1',?";, Date S-/5-&
Location: Dn C.:2@,...<YTA:9 (btwn/at) A«c;,.-G (and) C.. v<.-1,ecz,y.Ah_.,
Day/Direction
Time Period ~e, 7%-/4,g
0000-0100 /0
0100-0200 ~
0200-0300 """3,
0300-0400 Z-
0400-0500 -z_..
0500-0600 ;3
0600-0700 (p Z,
0700-0800 '7g
0800-0900 /OZ.,
0900-1000 6&>
1000-1100 g,7
1100-1200 ~'1
1200-1300 qq
1300-1400 </C}
1400-1500 6,7
1500-1600 S'S
1600-1700 /)
1700-1800 Y?/4
1800-1900 7'1
1900-2000 67 8 '
2000-2100 c;.o
2100-2200 3/
2200-2300 -z,...&,
2300-2400 -zo
TOTAL(S) ,;-e,5 7-Z~
PEAK HOUR(S)
PEAK FLOW(S)
Special conditions or remarks: ____ ....,... ______________ _
ADI-==-\,~\\
TRAFFIC COUN>-\TA SHEET
TS# __ _
Street(s)
Count Datez2-B·$0 8-l~~Data Reduction byN'-.Q '? Date Fz-\S-B::
Location:-On U,£.,,u77A (btwn/at) 4.!..-&7A-(and)?oC-C>7"J.?Q L.,,.._
Day/Direction
Time Period /,(/ /28 r,;,;,/-?8
0000-0100 s
0100-0200 z..
0200-0300 I
0300-0400 0
0400-0500 '--
0500-0600 //
0600-0700 ~-:3
0700-0800 ~z..
0800-0900 7/
0900-1000 70
1000-1100 7/
1100-1200 !/-'?
1200-1300 C;,t,
1300-1400 ~
1400-1500 ~o -'
...
1500-1600 1S I
1600-1700 L/-(,,
1700-1800 07
1800-1900 37
190~-2000 "30
2000-2100 /6
2100-2200 /t/
2200-2300 IL/
2300-2400 g,
TOTAL(S) "323 "l-~1
PEAK HOUR(S)
PEAK FLOW(S)
Special conditions or remarks:: ___________________ _ --
..,, ... .i'I'
TS# __ _
Street(s)
\
TRAFFIC COUNT ~ .I SHEET
Count Da te:$-Z-7-e%,to B--Z.8-'Bt,, Data Reduction by,,v,>1,J 7 Date S-2-~-Sc.:.
Location: On At-&A (btwn/at) C::a(Z./,yr;4 (and) C:::,a; ::o/?5:S:O
Day/Direction
Time Period ¾s ~
0000-0100 GO
0100-0200 31
0200-0300 C,
0300-0400 7
0400-0500 &
0500-0600 &,
0600-0700 C/-;:,
0700-0800 IZ/
0800-0900 /7'7
0900-1000 ;csz
1000-1100 ;e,q .
1100-1200 /73
1200-1300 zo7
1300-1400 Z3f!3
1400-1500 Z/3
1500-1600 -z_oJ
1600-1700 ~:32-
1700-1800 c;zg
1800-1900 :5?'1
1900-2000 2I37 '
2000-2100 207
2100-2200 /82
2200-2300 /27
2300-2400 0C,
T0TAL(S) z, /0) z., idZS
PEAK H0UR(S) -
PEAK FL0W(S)
Special conditions or remarks:, ____ ~-::-:-=;-------------
AD; -:3,6\/
TRAFFIC COUNT :rA SHEET
TS// ---
Street(s)
Count D"ate,g-z::7~f¼ to B-Z-6-8"~
Location: On ,41,44
Time Period N /41.3 7"¼8
0000-0100 / l.f
0100-0200 q
0200-0300 ~
0300-0400 3
0400-0500 7
0500-0600 '3<')
0600-0700 IZC;
0700-0800 ZZ7
0800-0900 Z.Z-Z,.
0900-1000 /,f,j,
1000-1100 /t/-7
1100-1200 /Ljg
1200-1300 /7/
1300-1400 Jt/-7
1400-1500 107
1500-1600 !ZCP
1600-1700 z_o-z.,.
1700-1800 I") OJ
1800-1900 /7~
1900-2000 J3Cj ' 2000-2100 0/
2100-2200 (p"J
2200-2300 '?Z
2300-2400 32-
TOTAL(S) jt:J&,4-l,"3?/
PEAK HDUR(S)
PEAK FLOW(S)
Data Reduction by /J?(,1:"2 ,
(btwn/at) c:'o/e./Nr(d
Day/Direction
U-8i
Date B-Z...C:,-~
(and) :'.7,A',1..,7;4 /~AB6"
Special conditions or remarks:, _______ :::--------------
AD; z,c:.75
4-22-SIGNS TRAFFIC MANUAL
April 1975 ----------------------------------------"'
4--03.3 Design, Policy and Location for Individual Signs
Rl
White on Red
30• octagon
10• Series C' letten
(f,,.lso available in
24•. 36., and 4• sb:esJ
Policy: The Rl sign shall be used on public roads
where a stop is required. Stop signs shall be erected
on both the left and. right side of one~way roadways
which are 30 feet or more in width. Stop signs shall
not be installed at signalized intersections.
Conditions warranting STOP signs are:
. 1. On the less important road at its intersection
with a main road where application of the nor-
mal right of way rule is unduly hazardous as
evidenced by accidents susceptible of correc-
tion by STOP signs.
2. On a county road or city street at its intersec-
tions with a state highway.
3. At the intersection of two main highways. The
highway traffic to be stopped depends on ap-
proach speeds, volumes, and turning move-
ments.
4. On a street entering a legally established
through highway or street.
5. On a minor street where the safe approach
speed to the intersection is less than 10 miles per
hour.
A STOP sign is not a "cure-all" and is not a substi-
tute for other traffic control devices. Many times the
need for a STOP sign can be eliminated if the sight
distance is increased by removing obs_tructions.
. The installation of STOP signs at locations where
they are unexpected or where approach speeds are
high should be avoided if possible because they may
increase accidents. However, if there is no alterna-
tive to a STOP sign, then an advance Code Wl7
STOP AHEAD sign and appropriate pavement
markings should be placed in conjunction with it.
Publicity through the radio and press is highly de-
sirable when STOP signs are installed and especially
when it is necessary to change their location.
Any of the following conditions may warrant a
four-way stop sign installation:
1. Where traffic signals are warranted and the
need is urgent, the four-way stop is an interim
measure that can be installed quickly to control
traffic while arrangements are being made for
the signal installation.
2. An accident problem, as indicated by five or
more reported accidents of a type susceptible of
correction by a four-way stop installation in a
12-month period. Types of accidents susceptible
of correction ipclude right angle and left tum
collisions.
3. Minimum volume warrant:
a. The total vehicular volume entering the in-
• tersection from all approaches must average
at least 500 vehicles per hour for any eight
hours of an average day, and
b. The combined vehicular and pedestrian vol-
ume from the minor street or highway must
average at least 200 units per hour.for the:
same eight hours with an average delay to
minor street vehicular traffic of at least 30
seconds per vehicle during the maximum
hour.
c. When the 85-percentile approach speed of
the major street traffic exceeds 40 miles per
hour, the minimum vehicular volume war-
rant is 70 percent of the above requirements.
A four-way stop sign installation is a useful traffic
control measure when other available means of con-
trol are not adequate. It should not be used unless the
volume of traffic on the intersecting roads is about
equal and is undesirable at low-volume intersections.
When STOP signs are placed on all entering legs
of an intersection, each STOP sign may be supple-
mented by a separate plate mounted below it with
the message ''.3-WAY", "4-WAY", etc. The supple-
mental plate shall have white letters on a red back-
ground.
Location: Erect in the standard position on the
right or left at or near the entrance to an intersection
or at any location necessary to control traffic within
an intersection.
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