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Home My WebLink AboutNB 4 SIGNAL WARRANTS 07-06-82: 3DATE Inter - C om TO: FROM: SUBJECT: WILLIAM HUSTON, CITY MANAGER NORM HOWER, TRAFFIC ENGINEER SIGNAL WARRANTS - YORBA STREET AND VANDENBERG LANE As requested by the City Council, the intersection of Yorba Street and Vandenberg Lane has been investigated for meeting the warrants for a traffic signal installation. Attached are the signal warrants and a cumulative collision diagram for the intersection. A search through the Engineering records has indicated a total of three accidents in the intersection during the period of January 1, 1977 to May 31, 1982. The number of accidents used in the warrants was for the 12 months of 1981. This intersection does not meet any of the warrants for traffic signal control. NORM HOWER TRAFFIC ENGINEER db Attachments TRAFFIC SIGNALS AND LIGHTING Traffic Manual Figure 9-1A TRAFFIC SIGNAL WARRANTS CALC CHK Major St: ~/'~/~ ~,A Minor St: V',~,,~//D~/ ~/Z ~ Criticat s0eed of major street ~raffic -- 40 mph In built up area of isolated community of .~. 10,000 pop ......... Critical Approach Speed 4~" ~ mph Critical Approach Speed ~_~__ mph RURAL {RI URBAN (U) WARRANT 1 - Minimum Vehicular Volume MINIMUM REQUIREMENTS 100% SATISFIED Yes [] No (so~ s.ow. ~. S,ACKtTS~ 80% SATISFIED Yes u I ' u I R , , · , - , , , /. ,°/..,t.a/.,'. ~..~oAc~N~s ~ ~e. ~' /~'~I~v/~'~'I~'~'I~'~'I~'~'IV~' Both ApDrc~. ~ 3~ ~ 420 Hig~st A~C~ I~ 105 2~ ' NOTE: Heavier of left turn m~nt f%om Major Strut i~1~ w~n gT-phesi~ ts proposed WARRANT 2 - Interruption of Continuous Traffic Hour MINIMUM REQUIREMENTS 100% SATISFIEO Yes [] No I I / S0%~ATISFIED Yes [] NO Uj R Uj F1 / ~' 0 ~0 / / / · / 0 0 o O O o ~ · A,,,',~O~C, .,0 ,o/..~ ..o/.,.o oo/.o ~/.~ ~/,~.o / ~,.Es ~ ~ ~ ~e ~ ~' I~ ~ /~ ~. Ix' ~1~' ~' I~' ~'/fi' ~'/~' ~' Ho~ ~th A~9~s. 7~ 525 ~ Hig~st Ap~ch 75 ~ 1~ 70 Minor Str~t' ~60) (42] <80) (56) /~/ ~ /~3 /~/ ~ ~ NOTE: Heawer of left turn move~nt fr~ Ma/or Str~ ~1~ when LT-phas~ ~S p~o~os~ WARRANT 3 - Minimum Pedestrian Volume MINIMUM REQUIREMENTS U R 600 420 1000 700 ~05 184) Ek~th Apprchs, No Median ~ior S~'reet Volume Raise(t 4' Median Pe~'s On Highest Volume x-Walk Xing ~jor Street IF MIOBLOCK SIGNAL 100~ SATISFIED Yes [-[ No [~ 80°/, SATISFIED Yes [] No/~' /////// [] N/E ft S/W ftJ Yes [] No [] Hour 150 Feet WARRANT 4 - School Crossings Not Appl icabte See School Crossings Warrant Sheet Traffic Manual TRAFFIC SIGNALS AND LIGHTING 9-5 12.19'!6 Figure 9:1B TRAFFIC SIGNAL WARRANTS WARRANT 5 -- Progressive Movement 8atisfic~ Yes [] No ~ MINIUUld RE(~UtR£MENT$ DISTANCE TO N[AREST SIGNAL FULFILLED > 1~ ft N 7~o , S~ft, E ~ fi, W ~ ft YES~ NO~ ON I$OLATEO ON[ WAY ST. OR ST, WITH ON[ WAY TRAFFIC SIGNIFICANC[ AOJACENT SIGNAL5 WARRANT 6 - Accident Experience Satisfied Yes 0 RE[QUIREMENT WARRANT aO% -- --~31~ ............................ · NOTE, Left turn acc/dents can Oe Included when I..T-Df~asing ts proposed No ~ WARRANT 7 -- Systems Warrant Satisfied Yes [] VI[H/HR No ~ FULF~i. LE.D YESES' NO [] WARRANT 8 -- Combination of Warrants (Used if nO one warrant satisfied 100%) Sat isf ied REQUI Rt=MENT WARRANT TWO WARRANTS 1 -- MINIMUM VI[HICU~AR VOLUMI[ ~ATISFIED 2 - INT[RRUPTION OF CONTINUOUS TRAFFIC Yes [] NO ~ The satisfaction of a warrant is not necessarily justification for signals. Delay. congestion, confusion or other evidence of the need for right of way assignment must be shown. V'AfdPF, kI¢6~ ii/= ~,~1 INTERSECTION VOLUMES YORBA STREET AND VANDENBERG LANE YORBA STREET VANDENBERG NORTH SOUTH TIME BOUND BOUND TOTAL WEST BOUND 12:00- 1:00 AM 10 16 26 1:00- 2:00 11 15 26 2:00- 3:00 2 11 13 3:00- 4:00 9 10 19 4:00- 5:00 5 2 7 5:00- 6:00 21 20 41 6:00- 7:00 62 168 230 7:00- 8:00 146 459 605 8:00- 9:00 164 226 390 9:00-10:00 174 187 361 10:00-11:00 178 177 355 11:00-12:00 269 188 457 12:00- 1:00 PM 290 247 537 1:00- 2:00 220 218 438 2:00- 3:00 213 184 397 3:00- ¢:00 329 199 528 4:00- 5:00 762 259 1021 ~:00- 6:00 614 202 816 6:00- 7:00 235 171 406 7:00- 8:00 129 129 258 8:00- 9:00 88 90 178 9:00-10:00 63 70 133 10:00-11:00 53 77 130 11:00-12:00 21 35 56 12 4 2 1 9 13 81 i61 114 74 74 96 123 121 91 69 89 91 85 46 42 24 27 12 INTERSECTION TOTAL 38 30 15 20 16 54 311 766 504 435 429 553 660 559 488 597 1110 907 491 304 220 i57 157 68 8,889 ~'~AFFIC I NFOP~MAT I 0N PROGRAM 'Ti AFFIC eSIGNAL DOES SOMEBODY HAVE TO'BE KILLED BEFORE A TRAFFIC SIGNAL WILL BE INSTALLED?. Traffic signals don~t always prevent accidents. They are not always an asse~ to traffic control. In some instances, total accidents and severe injuries increased after signals were installed. Usually; in such instances, right angle co!lisions were reduced by the traffic signals, but the total number of. collisions, especially the rear-end type, increased. There are times when the installation of signals results in an increase in pedestrian accidents. Many pedestrians feel secure with a paintec~.,crosswatk and a red light between them and an approaching vehicle. The motorist, on the other hand, is not always so quick to recognize these "barriers." When can a traffic signal be an asset instead of a liability to safety? In order to answer this, traffic engineers have to ask and answer a series of questions: 1. Are there so many cars on both streets that signal controls are necessary to clear up the confusion or relieve the congestion? 2. Is the traffic on the main street so heavy that drivers on the side street will try to cross when it is unsafe? 3. Are there so many pedestrians trying to cross a busy main street that confusing, congested or hazardous conditions result? 4. Are there so many school children trying to cross the street at the same time that they need special controls for their protection? If so, is a traffic signal the best solution? 5. Are signals at this location going to help drivers maintain a uniform pace along the route without stopping unnecessarily? IM~1-77 Southern California Section 6. Does the collision history indicate that signal controls will reduce the probability of collisions? 7. Do two arterials intersect at this location and will a signal help improve the flow of traffic? 8. Is there a combination of the'above conditions which indicates that a signal will be an improvement rather than a detriment? 'To aid them in answering these questions, engineers coml3are the existing conditions against nationally accepted minimum guidelines. These guidelines (often called "Warrants") were established from many observations at intersections throughout the country by experienced traffic engineers. Where the guidelines were met, the signals generally were operating effectively with good public compliance. Where the guidelines were not met, public compliance was reduced, and additional hazards resulted. A traffic signal that decreases accidents and improves the flow of traffic is an asset to any community. On the other hand, an ill-advised or poorly designed signal can be a source of danger and annoyance to all who use the intersection; pedestrians, cyclists and drivers alike. IM/1-77