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HomeMy WebLinkAbout1993-04-05; Traffic Safety Commission; ; Investigate various modifications to the Alga Road/Cazadero Drive intersection to improve sight distance visibility.CI1Y OF CARLSBAD TRAFFIC SAFE1Y COMMISSION STAFF REPORT COMMISSION MEETING OF: April 5, 1993 ITEM NO. 6A LOCATION: Alga Road/Cazadero Drive intersection INITIATED BY: Karen Campbell, 7141 Argonauta Drive, Carlsbad, CA 92009 REQUESTED ACTION: Investigate various modifications to the Alga Road/Cazadero Drive intersection to improve sight distance visibility. BACKGROUND: DATA: At the June 1, 1992 Traffic Safety Commission meeting, Ms. Campbell asked for a study of potential improvements to the intersection. She requested that either a traffic signal be installed at the intersection or that Cazadero Drive be considered as a ONE-WAY street southbound from Alga Road to Luciernaga Street. The Commission indicated to Ms. Campbell that the issue would return to the Traffic Safety Commission after staff has conducted necessary traffic studies. Ms. Campbell was also advised that the intersection is ranked Number 11 on the City of Carlsbad 1992 Traffic Signal Qualification List. Alga Road is classified as a major arterial on the · City of Carlsbad Circulation Element. The roadway is 82' wide within a 102' right-of-way with an 18' wide raised median and left-tum lanes on Alga Road provided for both directions of travel at Cazadero Drive. Sidewalks are not constructed along Alga Road in the vicinity of the Cazadero Drive intersection. The roadway at the subject intersection has a curvilinear alignment. Cazadero Drive is considered a collector street connecting a series of local and cul-de-sac streets to Alga Road. Cazadero Drive is 40' wide curb-to-curb within a 60' wide right-of-way. There is existing curb, gutter and sidewalk on both sides of Cazadero Drive. Between Luciernaga Street and Alga Road, a distance of approximately 150 feet, there are no homes that front or take access onto Cazadero Drive. The intersection of Cazadero Drive with Alga Road creates a four-leg intersection. Alga Road, Cazadero Drive and the adjacent streets were constructed in the early 1970's as a part of the La Costa Meadows Land Development. From 1992 traffic counts obtained in the project vicinity, Alga Road westerly of Cazadero Drive has Average Daily Traffic (ADT) volumes of approximately 15,400 and Cazadero Drive southerly of Alga Road has approximately 1,200 ADT. Staff conducted vehicle turn movement counts to determine proportional splits of traffic moves, i.e., left-turns, right-turns, and through traffic. A summary of 24-hour average daily traffic counts are shown on Exhibit 2 and peak hour turn movements are shown on Exhibit 3. CI1Y OF CARLSBAD TRAFFIC SAFE'IY COMMISSION Staff Report COMMISSION MEETING OF: April 5, 1993 ITEM NO. 6A ( continued) Staff researched the previous five year collision history of the subject intersection. For the five year period from January 1988 through December 1992, there were eight reported collisions at the Alga Road/Cazadero Drive intersection. Of these collisions, three were right angle collisions resulting from the violation of right-of-way and are shown on the collision diagrams, Exhibit 4. However, only one collision resulted from a northbound vehicle on Cazadero Drive attempting to tum onto Alga Road. Staff has evaluated six ( 6) alternatives for the Alga Road/Cazadero Drive intersection. The evaluations include cost estimates and discussion of advantages and disadvantages of each alternative. At this time, no funding has been secured for any of the alternatives. Given the fiscal outlook for Carlsbad, it is uncertain when funding will be available in the short-term for modifications to this intersection. ALTERNATIVE NO. 1: Install a traffic signal including an "Advance Warning" device. The Alga/Cazadero intersection was evaluated upon criteria contained in the City of Carlsbad Traffic Signal Evaluation Policy. A methodology is contained in this policy that provides for a logical method of comparing intersections using such factors as volumes, pedestrians, school crossings, accident experience, delays, and special conditions. Using this criteria, the intersection was ranked Number 11 on the City of Carlsbad 1992 Traffic Signal Qualification List. Advantages Installation of a traffic signal provides positive right-of-way assignment for both vehicles and pedestrians. Each different tum movement at the intersection can be included in the signal phasing. Disadvantages The intersection is within 1,200' of an existing traffic signal at the Alga Road/Corintia Street intersection. The obvious imbalance of through traffic volumes (15,000) on Alga Road to side street traffic volumes (1,100) on Cazadero Drive could result in unnecessary delays and longer queues at this intersection than currently exists without the traffic signal. The installation of poorly located or marginally warranted traffic signals has the potential to increase certain types of collisions. By placing the signal at the top of a long grade, more people would tend to "run" the signal, trying to keep their momentum up the hill. In time, advance warning beacons would become less effective to warn oncoming motorists of the "Signal Ahead" situation and the stopped vehicles on Alga Road at the traffic signal. CI'IY OF CARLSBAD TRAFFIC SAFEIY COMMISSION Staff Report COMMISSION MEETING OF: April 5, 1993 ITEM NO. 6A ( continued) The construction cost, including traffic signal design, is estimated at $100,000 and includes two "Signal Ahead" flashing beacons. An additional cost that must be considered is the yearly operation and maintenance expense of the traffic signal. A typical traffic signal in Carlsbad costs about $5,000 per year to maintain and operate. ALTERNATIVE NO. 2: Construct a 300' long, two to three foot high retaining wall along the south side of Alga Road, west of Cazadero Drive. Remove the majority of vegetation to increase sight visibility. The construction of a retaining wall and the removal of slope vegetation and trees would be an improvement to the existing condition. With the retaining wall in place and the vegetation removed, the available sight distance would be increase slightly. The estimated cost of retaining wall and clearing of vegetation is $30,000. Relocation of utilities would add additional expense. Advantages • The construction of a retaining wall and the removal of slope and landscaping would improve sight distance slightly at this intersection for northbound left turning vehicles turning west on Alga Road from the south leg of Cazadero Drive. Disadvantages The construction of a retaining wall and the removal of slopes and vegetation would only slightly improve visibility to this intersection. Because of the horizontal and vertical alignment of Alga Road, this improvement alone would not substantially increase sight distance. ALTERNATIVE NO. 3: Close the southerly leg of the Alga Road/Cazadero Drive intersection between Alga Road and Lucieranga Street. By totally closing this leg of the intersection, access to and from Cazadero Drive to the south side would be physically eliminated. The intersection would become a "T' intersection with access to and from the north leg only. If implemented, the construction would consist of median re-construction and curb and gutter extension across the south side of Alga Road. The eastbound to northbound left-tum lane would remain viable, but the westbound Alga Road to southbound Cazadero Drive left-tum lane would be eliminated. On Luciernaga Street, curb, gutter and sidewalk would be constructed across the existing street opening. A storm drain inlet would need to be relocated and the sewer, water, and utility facilities could remain in place. CI1Y OF CARLSBAD TRAFFIC SAFE1Y COMMISSION Staff Report COMMISSION MEETING OF: April 5, 1993 ITEM NO. 6A ( continued) Northbound Cazadero Drive traffic volumes would divert to Corintia Street, via Luciernaga Street and then to Alga Road. The Alga Road/Corinita Street intersection is signalized. Based upon 1992 data, approximately 700 vehicles could be added to the daily 2,700 vehicles using Corintia south of Alga Road. Staff considered the current and proposed levels of service to the Corintia/Alga intersection and roadway. The existing levels of service are considered excellent with very little congestion and delay observed. The additional traffic would have a negligible impact on roadway and traffic signal operations. The estimated ADT of Corintia Street south of Alga Road would be approximately 3,400 vehicles. The estimated ADT of Luciernaga Street easterly of Cazadero Drive would increase by approximately 700 vehicles. These volumes would not exceed the capacity of the roadways. The Fire Department considered the effect of travel time and access to the neighborhood south of Alga Road. The general response time of five (5) minutes would not be affected by this closure and, in case of emergency, additional access is available. No violations of existing cul-de-sac policies or standards are created by this closure. The estimated cost of constructing a total closure of this leg of the intersection is approximately $30,000. Disadvantages The total closure of Cazadero Drive between Alga Road and Luciernaga Street is considered excessive and unnecessary. The collision history from vehicles entering this intersection does not indicate the need to preclude certain turn movements that would result from the total closure of the south leg. Out of direction travel would result with increases in fuel usage, noise, and air pollution as a result of longer travel distances. ALTERNATIVE NO. 4: Modify Cazadero Drive to provide for southbound ONE-WAY travel only from Alga Road to Luciernaga Street. Thir. alternative would permit only entering traffic volumes to proceed southbound from Alga Road to Luciernaga Street. To implement the partial closure, the roadway would be reduced to a 18' to 20' wide section for the road segment from Alga Road to Luciernaga Street. Sidewalk, curb, and gutter would be reconstructed. ONE- WAY traffic would allow westbound left-turns in, eastbound right-turns in, and through movements from the north to southbound Cazadero Drive. With this CI1Y OF CARLSBAD TRAFFIC SAFE1Y COMMISSION Staff Report COMMISSION MEETING OF: April 5, 1993 ( continued) ITEM NO. 6A alternative, it is estimated that approximately 600 ADT would be diverted to Corinita Street. The construction cost for this alternative is estimated at $15,000. Disadvantages Converting a short segment of Cazadero Drive to a ONE-WAY street would cause some out of direction travel. Local residential streets would experience an increase in traffic volumes and noise. ALTERNATIVE NO. 5: Construct raised channelization to eliminate the northbound left-turn movement. One method for controlling turning movements at an intersection is to construct raised channelization. A type of raised channelization to restrict a turning movement is sometimes called a "pork chop". This physical device is effective in eliminating the undesired turning movement. Advantages The raised channelization will help prevent the undesired northbound left turn movement but allow the northbound right turn movement. All other turning movements at the intersection are unaffected. This raised channelization can be constructed by the City of Carlsbad Utilities and Maintenance Department for an estimated cost of approximately $1,500. Disadvantages Once constructed, the raised channelization is an obstruction in the roadway that may be struck by a vehicle. However, signing and striping will help vehicles avoid the raised channelization. Some out of direction travel will be required for the vehicles currently turning left from Cazadero Drive to proceed to the Corintia Street/Alga Road intersection so that westbound travel on Alga Road can occur. The raised channelization will not completely prevent a vehicle from making an illegal left turn if the driver chooses to negotiate the maneuver. ALTERNATIVE NO. 6 -DO NOTHING: The Alga Road/Cazadero Drive intersection was constructed approximately 20 years ago. Development in this area has been steady and today the area is considered established with only a few remaining lots to build upon. A significant increase in traffic volumes at this intersection is not expected. Fortunately, the accident rate of CI1Y OF CARLSBAD TRAFFIC SAFE1Y COMMISSION Staff Report COMMISSION MEETING OF: April 5, 1993 ( continued) ITEM NO. 6A this intersection is low. Additional advance warning signs, aggressive landscape trimming, and continuous police enforcement could help maintain the low collision rate. RECOMMENDATION: The Traffic Safety Coordinating Committee recommends that Alternative Number 5 be implemented. NECESSARY CI1Y COUNCIL ACTION: City Council concurrence of this alternative will be required and to authorize the Utilities and Maintenance Department to construct the raised channelization including signing and striping. _., 4"Je:::,~B,PN IH33N IDNJ uv :JO AU::J Z66l 6 Nnr ClJ141a:~n1a ~? ~') '~ 'A /') ~ ... l: l I I, ' ' l (.. 7 :1 .~ ~-IP701 {,/~ • y ; J ~ ~~ -~ 7 / 7 ~~ .__'--'"P",,_ ;zl ~ :I ---+------~-~~ / 7 J-f ~ y!/f). ;1 -}J7X) ~?t~ xft. : l , l\ . L t• I . L :l cX I : d~CtU-r I ??)~ zl,t.,i., 4~- i • ~(.J~'v t I RECEI VED ------JUt'i 9 1992 -------CITY OF CARLSBAD ENGINEERING DEPARTMEN T -----·-- LIST OF EXHIBITS EXHIBIT 1 Vicinity/Location Map EXHIBIT 2 24-Hour Traffic Counts EXHIBIT 3 Peak Hour Tum Movements EXHIBIT 4 Collision Diagrams EXHIBIT 5 Alternative 5 -Construct raised channelization to eliminate the left-tum movement. LOCATION MAP PROJECT lA CCJ../NlJR/N,,, JD SOCORRO LN. UNICIJRNID ST. ◄~,.◄ {(t\F PROJECT PROJECT NAME EXHIBIT ALGA RD. I CAZADER □ DR. 1 (7 /21/92) N 1%1 1992 TRAFFIC COUNTS L ----~7~ic s ,R[[1 w 417 ~ ~-----==:.,..:-;37;;--3 r-- r_~--(-10/-13-/-92) l ~\~ n \~ \r\)Ss z z --I (/) -4 (/) z (/)'r ~p -I ;j -I D J> --u r, 24 HOUR APPROACH VOLUMES 24 HOUR R □ADwA Y LINK VOLUMES LUCIERNAGA l r J> z -I (/) ,_. -I r D -u r7 (10/20/92) 157 323 STREET 1 1 n J> z (/) -I -I ,-+ r ALGA ROAD ~ ~ t~ (10/21/92) -----.. n (/) ~ -I >---1 . z -I >---1 J> LUCIERNAGA ---ST, EXHIBIT 2 N 1%1 1993 TRAFFIC COUNT S ALGA 70 ~ (/) z 4 4 (3 /23/93) 24 HOUR APPROACH VOLUME S EXHIBIT 2A 29 1992 ocrnBEl□uR 'rnRN ~Be~MENT COUNTS I -8:00 AM PEAK 7,00 EAK) (5:00 -6:00 PM p N IZI ALGA (117) (56\) (87) a:,o:>r-- (7) (281) (15) :) \ \... ~ '! \t LUCIERNAGA 25 _I (13) 14 ~ ( 4) 4 -----.. (2) ---.., r 1, (( ROAD STREET ALGA (66) (528) (99) LUCIERNAGA 15 _I 221 ~ 48 ~ (31) (239) (16) (24) (2) (0) ROAD STREET EXHIBIT 3 TRAFFIC COLLISION D IAGRAM CITY OF CARLSBAD TRAFFIC ENGINEERING DMSION LOCATION= DRAWN BY: DATE= REVISED BY: DATE= ALGA ROAD C.\./ICKHAM 3/23/93 I CAZADER □ DRIVE PERIOD: .JANUARY 1 , 1988 THRU DECEMBER 31 , 1988 PERIOD: NUMBER OF TRAFFIC COWSIONS BY TYPE YEAR 1988 N 1%1 TOTAL 1 I> VEH. @ fAUL T --I> VEH. MOVING r□RVARD ~ VEH. MOVING BACKVARD - --{> PEDESTRIAN C=> PARKED VEH. □ rIXED OBJECT 0 PROPERTY DAMAGE ONLY ® INJURY • fATAL cSt OUT-Of-CONTROL ROLLOVER --{>0<1--HEAD-ON PROP. NJURY FATAL DAMAGE LIGHT DARK WET 0 1 0 1 0 0 0"'9 ~\)'<''\) ~ <)1J '.<?<: , ~ 0 ~ r ~ LEGEND HEAD-ON SIDESVIPE PASSING SIDESWIPE RIGHT ANGLE PASSING TURN CONST ESS nc HBD HS.R !LC IP IT IS IB !NATT M/C CONSTRUCTION RSS RAN STOP/SIGNAL EXCEEDING SAFE SPEED VRW VIOLATED R-0-1,1 FOLLOWING TOO CLOSE WS WRONG SIDE HAD BEEN DRINKING DUI DRIVING UNDER INfLUENCE HIT S. RUN □TH OTHER IMPROPER LANE CHANGE IMPROPER PASS COLLISION DATA DESCRIPTION• IMPROPER TURN (COLLISION FACT.> <REP. #>I> IMPROPER START <DATD <TIMD IMPROPER BACK INATTENTION EXHIBI T 4A MOTORCYCLE TRAFFIC COLLISION DIAGRAM CITY OF CARLSBAD TRAFFIC ENGINEERING DMSION LOCATION: ALGA ROAD/ CAZADER □ DRIVE DRAWN BY: C.'w'ICKHAM DA TE: ____ 3_/_2_3_/_9_3 __ _ REVISED BY: DATE: ________ _ PERIOD: JANUARY 1 , 1989 THRU DECEMBER 31 , 1989 PERIOD: NUMBER OF TRAFFIC COWSIONS BY TYPE YEAR TOTAL PROP. DAMAGE 1989 2 1 RSS/H&R 89-4900 A.--51_2_6_1_a_9 ___ 2_1,2_s ___ _ N 1%1 (> VEH. i! FAULT ----{> VEH, MOVING FORIJARD ~ VEH. MOVING BACKIJARD - --[> PEDESTRIAN C=> PARKED VEH. □ FIXED OBJECT 0 PROPERTY DAMAGE ONLY ® INJURY • FATAL ct OUT-OF-CONTROL ROLLOVER --t>O<r-HEAD-ON ~ r ~ KJUAY FATAL 1 LEGEND HEAD-ON SIDESIJIPE PASSING SIDESIJIPE RIGHT ANGLE PASSING TURN 0 CONST ESS FTC HBD H&R !LC IP IT IS 1B !NATT MIC LIGHT DARK WET 1 1 0 CONSTRUCTION RSS RAN STOP /SIGNAL EXCEEDING SAFE SPEED VRIJ VIOLATED R-0-IJ F□LL□IJING TDD CLOSE \JS IJRONG SIDE HAD BEEN DRINKING DUI DRIVING UNDER INFLUENCE HIT 8, RUN IMPROPER LANE CHANGE 0TH OTHER IMPROPER PASS COLLISION DATA DESCRIPTION, IMPROPER TURN <COLLISION FACT.) <REP, U(> IMPROPER START <DATE> <TIME> IMPROPER BACK INA TT ENT ION EXHIBIT 4B MOTORCYCLE TRAFRC COLLISION DIAGRAM CITY OF CARLSBAD IBAFFIC ENGINEERING DMSION LOCATION: ALGA ROAD/ CAZADER□ DRIVE DRAWN BY: C.\./ICKHAM DATE: _____ 3_I2_3_/_9_3 ___ _ REVISED BY: DATE: ________ _ PERIOD: JANUARY 1 , 1990 THRU DECEMBER 31 , 1990 PERIOD: NUMBER OF mAFFIC COWSIONS BY TYPE YEAR 1990 N 1%1 TOTAL 1 (> VEH. @ FAULT ----{> VEH. MOVING r □R'JARD ~ VEH. MOVING BACK\IARD - --[> PEDESTRIAN C=> PARKED VEH. □ FIXED OBJECT 0 PROPERTY DAMAGE ONLY ® INJURY • FATAL c:St · □UT-OF-CONTROL ROLLOVER ---!>O<J--HEAD-ON PROP. DAMAGE 1 ~ r ~ FATAL 0 0 LEGEND CONST ESS . HEAD-ON SIDES\IIPE FTC PASSING SIDES'JIPE HBD H8.R RIGHT ANGLE !LC IP IT PASSING TURN IS IB !NATT MIC l.JQ-IT 1 CONSTRUCTION EXCEEDING SAFE SPEED F □LLD\IING TDD CLOSE HAD BEEN DRINKING HIT & RUN IMPROPER LANE CHANGE DAfl( 0 RSS VR'J 'JS DUI □TH WET 0 RAN STOP/SIGNAL VI□LATED R-□-'J 'JR□NG SIDE DRIVING UNDER INFLUENCE OTHER COLLISI□N DATA DESCRIPTION• IMPROPER PASS IMPROPER TURN IMPROPER START IMPROPER BACK INATTENTION MOTORCYCLE <C□LLISI□N FACT.> <REP. Ill(> <TIME> ·<DATE> EXHIBIT 4C lRAFFIC COLLISION DIAGRAM CITY OF CARLSBAD lRAFFIC ENGINEERING DMSION LOCATION: ALGA ROAD/ CAZADERD DRIVE DRAWN BY: C.'./ICKHAM DATE: ____ 3_/2_3_/_9_3 __ _ REVISED BY: DATE: ________ _ PERIOD: JANUARY 1 , 1991 THRU DECEMBER 31 , 1991 PERIOD: NUMBER OF lRAFFIC COWSIONS BY TYPE I YEAR 1991 N IZI I TOTAL 3 C> VEH. @ r AULT --{> VEH. MOVING rORlo/ARD ~ VEH. MOVING BACKlo/ARD - --I> PEDESTRIAN C=> PARKED VEH. □ FIXED OBJECT 0 PROPERTY DAMAGE ONLY © INJURY • FATAL 'at OUT-OF-CONTROL ROLLOVER --1>0<}-HEAD-ON PROP. INJl.f!Y I DAMAGE FATAL LD-fT DAAK WET 2 1 0 3 0 0 0~ \) '<'<::;; ~ '°-12> '.O <: ~ --12>o LEGEND CONST CONSTRUCTION RSS RAN STOP /SIGNAL ~ ESS EXCEEDING SAFE SPEED VR\ol Vl□LATED R-0-1,1 HEAD-ON SIDESl,IIPE rTC FOLLOl,IING TOD CLOSE \,IS \,/RONG SIDE PASSING SIDESl,IJPE HBO HAD BEEN DRINKING DUI DRIVING UNDER INrLUENCE r HS.R HIT !. RUN RIGHT ANGLE 0TH OTHER !LC IMPROPER LANE CHANGE JP' IMPROPER PASS COLLISION DATA DESCRIPTl□N• ~ IT IMPROPER TURN (COLLISION r ACT.) (REP, li)C> PASSING TURN JS IMPROPER START CDATD <TIME> 1B IMPROPER BACK !NATT INATTENTION EXHIBIT 4D M/C MOTORCYCLE TRAFFIC COLLISION DIAGRAM CITY OF CARLSBAD TRAFFIC ENGINEERING DMSION LOCATION: ALGA ROAD/ CAZADER □ DRIVE DRAWN BY: C.'v/ICKHAM DA TE: ____ 3_1_2_3_1_9_3 __ _ REVISED BY= DATE: _______ _ PERIOD: -.JANUARY 1 , 1992 THRU DECEMBER 31 , 1992 PERIOD: • NUMBER OF TRAFFIC COWSIONS BY TYPE YEAR 1992 N Ill TOTAL 1 (> VEH. @ FAULT --I> VEH. MOVING F □R\,'ARD ~ VEH. MOVING BACK\,'ARD - --{> PEDESTRIAN C=> PARKED VEH. □ FIXED OBJECT 0 PROPERTY DAMAGE ONLY 0 INJURY • FATAL at □UT-OF-CONTROL ROLLOVER ----t>O<r-HEAD-ON PROP. DAMAGE 0 ~ r ~ NJURY FATAL 1 LEGEND HEAD-ON SIDESVIPE PASSING SIDES\JIPE RIGHT ANGLE PASSING TURN 0 CONST ESS FTC HBO H&R !LC IP IT IS 1B !NATT M/C L.IGiT DARK WET 1 0 0 CONSTRUCTION RSS RAN STOP /SIGNAL EXCEEDING SAFE SPEED VR\,' VIOLATED R-□-IJ F□LL□VING T□□ CLOSE VS \,'RONG SIDE HAD BEEN DRINKING DUI DRIVING UNDER INFLUENCE HIT &. RUN IMPROPER LANE CHANGE □TH OTHER IMPROPER PASS COLLISION DATA DESCRIPTION: IMPROPER TURN <C□LLISI□N FACT.) <REP. #)(> IMPROPER START <DATD <TIMD IMPROPER BACK INA TT ENT ION EXHIBIT 4E MOTORCYCLE MODIFY SOUTH LEG CAZADER □ DRI 11 N □ L E F T T U R N 11 • ~of\'0 0 ~ 0 ~ 0 AL TERNA TI VE #5 EXHIBIT 5