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HomeMy WebLinkAbout1987-04-06; Traffic Safety Commission; ; The Traffic Safety Coordinating Committee recommends that neither a traffic signal or flashing beacon be installed at the Rancho Santa Fe Road/Cadencia Street intersectioCITY OF CARLSBAD TRAFFIC SAFETY COMMISSION COMM ISSI ON RE POR T OF : April 6, 1987 I TEM NO.6-A LOCAT ION: Rancho Santa Fe Road/Cadencia Street Intersection I NI TIAT ED BY: Frank Mannen, Assistant City Manager BA CKGROUND : At the Traffic Safety Commission meeting of March 2, 1987, the Commissioners postponed the request by Mr. Mannen to investigate the need for a traffic signal at the above referenced location until the April Traffic Safety Commission meeting. The Commissioners wanted to wait until after the public meeting regarding the alignment of Rancho Santa Fe Road was held on March 21, 198 7 before taking action. DA TA: Existing Roadway Condition s For a number of years the 2.7 mile segment of Rancho Santa Fe Road between Olivenhain Road and Questhaven Road was a rural two-lane road with two-way traffic a nd limited shoulder areas. Due t o its design ation as a prime arterial, a portion of RSF is being widened to six (6) lanes from Olivenhain Road to a point 4OO-feet north of Mision Estancia for northbound traffic and to a point approxim a tely 6OO-feet south of La Costa Avenue for southbound traffic. Although not designated a truck route , two lanes have been constructed for south- bound traffic from Questhaven Road to a point approximately one-half mile north of Ca dencia Street. Traffic signals have been installed where Olivenhain Road, Rancho Santa Fe Road and Cami no Alvaro i ntersect and also at the intersection of La Costa Avenue and Rancho Santa Fe Road. In conjunction with the widening of Rancho Santa Fe Road, traffic signals will be installed at two (2) a d ditional intersections -Mision Estancia and Calle Barcelona. TRAFFIC SA FET Y COMMISSION COMMISSI ON REPOR T OF: April 6, 1987 Continued Traffic Volumes ITE M N0 .6-A From a traffic count taken in January, 1987, the two-way 24- hour A.D.T. volume on Rancho Santa Fe Road at Cadencia Street was 14,811 vehicles. At Melrose Drive the two-way 24-hour A.D.T. volume on RSF is 18,346 vehicles. Accidents A colli sion diagram for the Street i ntersection accidents inclus ive is provided. Rancho Santa Fe for the years Road/Cadenci a 1983 to 1986, Interse ction of RSF and Cadencia Street Cadencia Street, a residential street, intersects Rancho Santa Fe Road to create a "T" intersection approximately 0.75 miles north of La Costa Avenue. Sight distance on RSF north of the i ntersection is limited due to a crest vertical curve. Howeve r , the available stopping sight distance on RSF when approac h i ng Cadencia Street from the north is approximately 460-feet which is sufficient for the 45 MPH posted speed limit on Rancho Santa Fe Road. The 24-hour two-way A.D. T. on RSF at this location is 14,811 vehicles and the 24-hour A.D. T. approach volume on Cadencia Street i s 553 vehicles as shown on the attached Traffic Count Data She ets. During 1986, there were four (4) reported intersection acci- dents at this location. Two (2) of the accidents were due to a violat ion of right-of-way and two (2) due to excessive speed. In 1984 and 1985, respectively , there was one (1) and two (2) reported accidents at the intersection of Cadencia Street and Rancho Santa Fe Road. As ind icated by the traffic counts, volumes are very low on Cadenc ia Street. Traffic signal warrants (attached) are not met at t his intesection when evaluated for volume or acc i dent exper ience. The CA LTRANS Traffic Manual states that the installation of a flashing beacon for advanced warning for may be warranted under one or more of condi tions: an intersection the following TRAFFIC SAFETY COMMISSION COMMISSION REPORT OF: April 6, 1987 Continued ITEM NO.6-A a. Physical obstruction existing in the roadway or reduction in width. b. Important intersection hidden by an obstruction or sharp curve in the highway. c. Potentially hazardous horizontal or vertical alignment. d. On the approach to a signalized intersection. A side street warning sign has been previously installed on Rancho Santa Fe Road advising motorists of Cadencia Street. Based upon CALTRANS criteria (warrants) for flashing beacons for advance intersection warning, the available sight distance and the accident history, flashing beacons are not required at this intersection. Future Alignment of Rancho Santa Fe Road At the direction of the City Council, a public meeting was held on March 21, 1987 to receive input regarding the alignment of Ranch Santa Fe Road. Basically, the citizens objected to the pr11me arterial street classification of Rancho Santa Fe Road and did not want the road constructed in the La Costa area, especially near the homes on the existing Rancho Santa Fe Road alignment. An Environmental Impact Review (EIR) will be prepared to evaluate the impacts from up to three (3) different alignments. The City Council will determine the final alignment of the road. RECOMMENDATION: The Traffic Safety Coordinating Committee recommends that neither a traffic signal or flashing beacon be installed at the Ra ncho Santa Fe Road/Cadencia Street intersection since warrants are not met. NECESSARY COUNCIL ACTION: No Council action is required for the recommendations. traffic signal or flashing beacon is recommended by Commission, then the City Council will need to approve installation and appropriate funds. If a the the --~ D IAGRA II COLLISION lOCAIIOH fc::::.o.......,,,_c..~ L...:,..~~o.. ~<:!-~~- I I & C:...~a..~c...~ '"==»'7 CITY OF CARLSBAD DIAWH ~~~ PUIOD . . . n TRAFFIC ENGINEERING SECTION DArl .,. •·6? 1-\-£3l:, \D I "Z.· 3, • -t5t- NO. ACCIDENTS SY TYPE TIA■ \C\B~ ~ ((( ► ---• c:=:> □ 0 © • rouL r ■o,. DA MAGI INIUIT PAT Al L-\-)) I l D V~'W-, ,-.\~"T"'\ o \ '-''-t-k I• c:;. • e,"' o?.c;.o''"' , ... )I' LEGEND VEH. MOVING AHEAD ~ HEAO•ON VEH. 8ACICING UP ... () HEAO•ON 510ESWIPE .. PEDESTRIAN ~ REAR ENO TRAIN () = OVERTAKING SIDESWIPE PARKED VEHICLE ~~~ RIGHT ANGLE f'IXEO OIJECT At>PIIOACH TURN PROPERTY DAMAGE ONLY ~. OV(RTAKINQ TURN INJURY ACC:10£NT ~ OUT o, C:ONTRO\. FATAL ACCIDENT -(5() ... VEHICLE TURN[O OV[R llOHf OAU WIT \\' \ c.:::> - CONST CONSTRUCTION ZONE CPO DRIVER PHYSICAL DEFECT ov DO'ECTIVE VEHICLE [5 EXCESS SPE[O fTC FOLLOWING TOO CLOSE H80 HAO BEEN ORINKINQ H-111 HIT AHO HUN .. ILC IMPROPEIII LANE CHANGE IP IMPROPER PASSINO IT IWPAOP[III TuAN ' !NATT INATTENTION MIC: MOTOflC:YCL[ 11155 RAN STOP SIGN OR SIGNAL SFP STOPPED 011 SLOWING FOIi P[OCSTRIAN VO V1S181l1TT ORSTRUCTCO VRW VIOLATED RIGHT 0, WAT ws WRONG SIC.( Q~ HRHT I GOLLISIOU DIArn,M LOCATION . • I CITY OF CARLSBAu • TRAFFIC ENGINEERING SECTION NO. TOTAL rao,. DAMAOI ~.A,,...?E-t-...lC.-\J::-- ((( ----• VEH. MOVING AHEAD VEH. 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DAM AG I INJUIY fATAl llGHT DAIK WIT \ N . ~ u} \.L D ~ ' d:' {) tJ 0 -:r u 2 a: <:x::: . LEGEND CONST CONSTRUCTION ZONE --..0.--OP!) DRIVER PHYSICAL OEFECT ... VEH. MOVING AHEAD HEAD-ON ov DEFECTIVE VEHICLE (E( ► VEH. IIACKING UP ◄ CJ HEAO·ON SIDESWIPE ES EXCESS SPEED ... ----• PEDESTRIAN ~ REAi! ENO FTC FOLLOWING TOO CLOSE n r;: l<BO HAD BEEN DRINKING TRAIN OVERTAKING SIDESWIPE H·II HIT ANO HUN c::::::> PARKED VEHICLE --~~ RIGHT ANGLE ILC IMPROPER LANE CHANGE □ FIXED OIJECT APPROACH TURN IP IMPROPER PASSING IT •-OPEii TURN 0 PROPEIITY DAMAGE ONLY ~ OVERTAKING TURN INATT INATTENTION ® INJURY ACCID£NT ~ OUT Of/ CONTROL M/C MOTORCYCLE • FATAL ACCIOf.NT 6<)..,;. VEHICLE TURNED OVEII ltSS RAN STOP SIGN OR SIGNAL SFP STOPPED OR SLOWING FOR PEDESTRIAN VO VISIBILITY OBSTRUCTED VRW VIOLATED RIGHT Of WAY ws WRONG SIC,[ OF STREET COLLI SI ON D IAGR i1 •• CITY OF CARLSB~D I ' TRAFFIC ENGINEERING SECTION LOCAYIOH DIAWH IY DATI NO. ACCIDENTS SY TYPE fOTAl Pao,. OA MAG I INJUIY fATAl ((( ► ► ----• VEH. MOVING AHEAD YEH. BACKING UP PEDESTRIAN TRAIN PARKED VEHICLE flXEO OIJECT PROPERTY DAMAGE ONLY IN.JURY ACCIDENT FATAL ACCIDENT LEGEND HEAD•ON HEAD·ON SIDESWIPE REAR ENO OVERTAKING SIOESWIPf RIGHT ANGLE APPROACH TUAN OV[RTAKINO TURN OUT Of CONTROl. VEHICLE TURNED OVER llOHT WIT 0 0 N CONST CONSTRUCTION ZONE OPO _DRIVER PHYSICAL OEl'ECT DV oE,ECTIVE VEHICLE ES EXCESS SPEED fTC FOLLOWING TOO CLOSE HBO HAO BEEN DRINKING H·R HIT AND RUN ILC IMPROPER LANE CHANGE IP IMPROPER PASSINO IT IMPftOPCR TURN IHATT INATTENTION M/C MOTORCYCLE IISS RAN STOP SIGH OR SIGNAL SFP STOPP(O Oft SLOWING FOR PEO£STRIAN VO VISIBILITY OBSTRUCTED VRW Vl«.AT[O RIGHT ~ WAY WS WROHO SIDE Of STR[ET 7~AFFrc cac~r DATA SHEE T TS• --- Count Date /?/ f1 to /· Z-3 $? 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I I I 1900-2000 I I 2 4 33 I i I 2000-2100 Z-0 '-, I ,:_. : I I : 2100-2200 c:, I I I ' 2200-2300 I /0 s I I I 2300-2400 ~ I -' ! ' '-'? 7QT ,1L(Si !'?/ SL\-~ '-+C z I I i =:::.1c: i'<CLR , 5) 1 I I I ,,,407- Traffic Manual TRAFFIC SIGNALS AND LIGHTING 9-1 12-1979 CHAPTER 9 TRAFFIC SIGNALS AND LIGHTING Traffic Signals-Basic Information and Warrants 9-01 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. ~hen jus~ified and properly designed, a traffic sig- nal installation may achieve one or more of the fol- lowing: 1. 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. Unjustifi_ed, ill-designed, improperly-operated, or poorly mamtamed traffic signals may cause: 1. 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, i~ is of the utmost importance that the consideratioo of a signal installation and the selection of equipment be preceded by a thorough study of traffic_ and roadway conditions made by an engineer expe_nenced.JI.Ild trained in this field. Equally impor- t~t 1s the need_fgr _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 fo r 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 of 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. 9-41.3 Warrant 1 -M inimum 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 of lanes for moving traffi c on each approach Vehicles per hour on major street (total of both approaches) Vehicles per hour on higher- vo lume mino r- s tre et approach Cone direction only) (Minimum Requirements) Ma jor Street Minor Street Urban Rural ~ Rural 1-,-----1-------500 j 50 150 105 2 or more --1 -------600 420 150 10 5 2 or more --2 or more •· 600 420 200 140 [ -------2ormore --500 350 200 140 9-2 12-1979 TRAFFIC SIGNALS AND LIGHTING Traffic Manual 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 turn 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. 9-01.4 Warrant 2-Interruption 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 of 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 (one direction only) (Minimum Requirements) Major Street Minor Street Urban Rural Urban ~ 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 turn 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. 9-01.5 Wanant 3-Minimum Pedestrian 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, ~Rural or more vehicles per hour enter the intersection ( total of both approaches) : or 1,000-U rban, 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 1., there are 150-Urban, 105-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. 9-01.6 Warrant 4-School Crossings See Chapter 10. 9-01.7 Warrant 5-Progressive 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 tw~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 &'>-percentile speed un- less an engineering study indicates that another speed is more desirable. The installation of a signal according to this war- Traffic Manual TRAFFIC SIGNALS AND LIGHTING 9-3 rant should not be considered where the resultant signal spacing would be less than 1,000 feet. Ml.I Warrant 6 -Accident Experience The accident-experience warrant is satisfied when: l. 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 pedestrian -volume warrant; and 4. The signal installation will not seriously disrupt progressive traffic flow. Ml.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- .. 12-1979 day, or each of any five hours of a Saturday and /or Sunday. A major route as used in the above warrant has one or more of the following characteristics: l. It is part of the street or highway system that serves as the principal network for through traf- fic flow; 2. It connects areas of principal traffic generation; 3. It includes rural or suburban highways outside of, entering or traversing a city; 4. It has surface street freeway or expressway ramp terminals; 5. It appears as a major route on an official plan such as a major street plan in an urban area traffic and transportation study. Ml .10 Warrant I -Combination of Warrants In exceptional cases, signals occasionally may be justified where no single warrant is satisfied but where any two of Warrants 1, 2 and 3 are satisfied to the extent of 80 percent or more of the stated numer- ical values for each of any 8 hours of an average day. Ml .11 Periodic Traffic Signal Studies To maintain the desirable operation" of existing traffic signals, it is necessary to periodically conduct engineering studies to en~ure that t~e des!red ope~a- tion is realized. In particular, engmeenng studies should determine whether the installation continues to be justified and that the signal timing in use meets the current traffic requirements.