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Home My WebLink About1994-05-02; Traffic Safety Commission; ; Mr. Jubb has been requested to remove a tree and rocks at the subject location. He has requested a Traffic Safety Commission review of the City Engineer's decisionCI1Y OF CARLSBAD TRAFFIC SAFEIY COMMISSION STAFF REPORT COMMISSION MEETING OF: May 2, 1994 ITEM NO. 6A WCATION: Northwest Corner of Chinquapin Avenue/Highland Drive INITIATED BY: William Jubb, 3993 Highland Drive, Carlsbad, CA 92008 REQUESTED ACTION: Mr. Jubb has been requested to remove a tree and rocks at the subject location. He has requested a Traffic Safety Commission review of the City Engineer's decision to have removed from the public right-of-way the pine tree and two rocks. BACKGROUND: DATA: Due to a pine tree growing on the northwest corner of the subject intersection, concerns have been expressed that there is a lack of adequate vehicular sight distance for eastbound vehicles stopped on Chinquapin Avenue at Highland Drive to observe southbound vehicles. Highland Drive is a local/residential collector street located in the northwest quadrant of Carlsbad extending from Adams Street on the south to its northerly terminus north of Ratcliff Road. Chinquapin Avenue is a local, east-west oriented street that terminates on the west at the railroad right-of-way and extends easterly to its terminus at Highland Drive. In general, unsignalized public road intersections should maintain a substantially clear line of sight between the driver of a vehicle waiting at a crossroad (Chinquapin Avenue) and the driver of an approaching vehicle on the main roadway (Highland Drive). This line of sight is called "corner" sight distance at an intersection. "Corner" sight distance requirements on a 2-lane roadway allows 7-1/2 seconds for the driver on the crossroad (Chinquapin Avenue) to turn left while the approaching vehicle travels at the assumed design speed of the main roadway (Highland Drive). Highland Drive has a design speed and a prima facie speed limit of 25 mph northerly of Chinquapin Avenue. The required "corner" sight distance for an intersection on Highland Drive is 275 feet based on the 25 mph design speed. "Corner" sight distance is measured from the location of the operator of the vehicle when the vehicle has been stopped at the stop LIMIT LINE ( operator of the vehicle is assumed to be 15 feet from the edge of the traveled way and the limit line assumed 6 feet from the edge of the traveled way per Caltrans criteria). Based upon field observations, when a vehicle is stopped at the stop LIMIT LINE on Chinquapin Avenue at Highland Drive, the motorist can see only approximately 150 feet to the north compared to the required 275 feet. However, when the motorist advances the additional six feet to the edge of the traveled way of Highland Drive, the motorist can see approximately 800 feet north to the intersection of Tamarack Avenue. These sight distance relationships are presented on EXHIBIT 1. CI1Y OF CARLSBAD TRAFFIC SAFE'IY COMMISSION STAFF REPORT COMMISSION MEETING OF: May 2, 1994 ( continued) ITEM NO. 6A Caltrans criteria states that when comer sight distance cannot be achieved due to high costs such as building removal, extensive excavation, or environmental costs such as tree removal, avoidance of wetlands, historic or archaeological sites, a lesser value than comer sight distance may be used. This value, however, shall be the stopping sight distance as a minimum. The field review of this comer also found two large rocks which have been placed in the public right-of-way between the edge of the roadway and the pine tree. Mr. Jubb, the property owner, admitted to staff that the rocks had been placed in the right-of-way adjacent to the roadway in an attempt to stop vehicles from intentionally cutting the comer and driving off the pavement. In summary, the required "comer" sight distance is currently not being provided at this intersection due to the location of the pine tree located in the public right-of-way. However, stopping sight distance is provided when the vehicle advances to the edge of the traveled way. The young pine tree which is growing at this comer will continue to grow larger and further restrict the required "comer" sight distance. It is not general City policy to plant trees in the public right-of-way. In addition, the pine tree is growing directly below and will conflict with the existing overhead utility lines requiring continuous and regular "topping" to avoid damage to the utility line. The two rocks located in the public right-of-way are an issue of potential liability to both motorists and the City and should be removed, as this is not an acceptable method to prevent vehicles from cutting a comer. Several options are available regarding these issues, as noted below: 1. Have City forces remove the pine tree and the two rocks from the public right-of-way. In addition, City forces could construct an asphalt berm, painted white along the edge of pavement around the northwest comer to help discourage drivers from cutting the comer. 2. Remove the branches of the pine tree from the ground up to a height of four feet and then monitor the growth of the pine tree and trim it back as required to maintain "comer" sight distance and to eliminate utility conflicts. City forces could remove the two rocks and could construct an asphalt berm, painted white along the edge of pavement around the comer to help discourage drivers from cutting the comer. 3. Remove the branches of the pine tree from the ground up to a height of four feet and then monitor the growth of the pine tree and trim it back as required to maintain "comer" sight distance and to eliminate utility conflicts. Leave the two rocks where they are in the public right-of-way. 4. Do nothing, but continue to monitor this location for problems in the future. CI'IY OF CARLSBAD TRAFFIC SAFE'IY COMMISSION STAFF REPORT COMMISSION MEETING OF: May 2, 1994 ( continued) ITEM NO. 6A If the pine tree is allowed to remain in its current location, even if the branches are removed from the ground up to a height of four feet, at some time in the future it will still interfere with the required "comer" sight distance due to the ultimate diameter of the tree trunk. In addition, when mature this tree will require periodic topping and trimming to eliminate utility conflicts overhead. By removing both the tree and the rocks, the existing and future problems can be eliminated without requiring a continuous monitoring and maintenance program at this location. RECOMMENDATION: The Traffic Safety Coordinating Committee recommends that the action items in Option 1, as indicated above, be implemented. NECESSARY CI'IY COUNCIL ACTION: No City Council action is required for the tree and rocks to be removed and the asphalt berm to be installed. LOCATION MAP TAMARA CK AVE . R/W I I E.P. ~--+-J0'--+---1~ NOT TO SCALE JUBB RESIDENCE 3993 HIGHLAND DR . ROCK PINE TREE I ROCK R/W---- 30' w'ly E.P. 1 PROJECTION CHINQUAPIN + 15•5• ~---j __ ,_ -- AVE. CD E.P. a: 0 0 z < _J :c C, I ~ 800 ft. ± SIGHT DISTANCE "-'150 ft .± SIGHT DISTANCE 275 ft. MIN. "CORNER" ) ( SIGHT DISTANCE REQUIRED CORNER SIGHT DISTANCE CD MOTORIST'S LOCATION WHEN STOPPED WITH FRONT BUMPER AT "STOP" LIMIT LINE 15 ft. w/o HIGHLAND DR. w'ly E.P. PROJECTION. (l) MOTORIST'S LOCATION WHEN STOPPED WITH FRONT BUMPER AT HIGHLAND DR . w'ly E.P. PROJECTION. NOTE: 1. IT IS 8 ft. FROM THE FRONT BUMPER OF A SEDAN TYPE VEHICLE TO THE MOTORIST OPERATING THE VEHICLE. 2. E.P .= EDGE OF PAVEMENT PROJECT NAME NORTHWEST CORNER OF EXHIBIT 1 CHINQUAPIN A VE./HIGHLAND DR. DRAWN BY: SCOTT EVANS, CARLSBAD ENGINEERING OCPT.