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HomeMy WebLinkAbout2005-01-03; Traffic Safety Commission; ; Investigate the need for a STOP sign on Unicornio Street at its intersection with Rancho Cortes( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: January 3, 2005 LOCATION: INITIATED BY: Unicornio Street at Rancho Cortes Ladi Hamer ( ITEMNO. 6B REQUESTED ACTION: Investigate the need for a STOP sign on Unicornio Street at its intersection with Rancho Cortes. BACKGROUND: Unicornio Street intersects Rancho Cortes in a T-intersection configuration. This intersection is in a residential area with Unicornio Street being the stem of the T-intersection (see Exhibit 1). No traffic control devices have been installed to assign the right-of-way at this intersection. DATA: Unicornio Street and Rancho Cortes are both considered local streets and neither is classified on the Circulation Element of the General Plan. When staff receives a request for STOP signs, the issue is reviewed thoroughly. STOP signs can cause substantial inconvenience to drivers and are intended to be used only where warranted. One of the conditions at an intersection that may warrant the installation of a STOP sign on the minor street is when, for sight distance purposes, the safe approach speed to the intersection is less than 10 miles per hour. The safe approach speed analysis is typically evaluated when there is a request to install a STOP sign on the minor street at an intersection. The minor street at a T-intersection is generally considered to be the stem of the T-intersection with the major street being the . top of the T-intersection. Each driver approaching an uncontrolled intersection has the intersection right-of-way assigned based upon the rules of the road. However, the dtiver should have an unobstructed view of the entire intersection and sufficient sight distance along the intersecting street for the driver to anticipate and avoid conflicts with approaching vehicles. A driver on the minor street (stem of the T-intersection), when approaching the major street, reaches a decision point location when braking to a stop, or substantially slowing the vehicle, is necessary if there is another vehicle approaching the intersection on the major street. The location of the decision point on the minor street must allow the driver to view, to the right and to the left, an approaching vehicle traveling on the major street. The driver on the minor street, generally not having the right-of-way, can then slow, stop, or avoid a conflict with other vehicles, as necessary, when the proper clear approach sight triangle is provided (see Exhibit 2). Conversely, the driver on the major street can see the approaching vehicle on the minor street when the clear approach sight triangle is established. ( CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: January 3, 2005 ( continued) ( ITEMNO. 6B On local streets, the minor street decision point location is assumed to be 50 feet from the intersection for an approach speed of 10 miles per hour. In general, a distance of 155 feet (stopping sight distance for 25 mph) along the major (local) street, or top of the T-intersection, needs to be provided to view vehicles approaching the intersection. However, when the grade of the major street exceeds 3 percent, a grade adjustment factor is applied to the length of the sight distance. For the subject location, the major street grade is 10.5% to the west and 5.5% to the east of the intersection. Therefore, an adjusted distance of 140 feet looking to the west and a distance of 155 feet looking to the east is necessary for the minor street driver to view vehicles approaching the intersection. If the major street vehicle cannot be seen by the driver at the decision point on the minor street, a STOP sign can be considered for installation on the minor street to assign the right-of-way. At the Unicomio/Rancho Cortes location, the driver on the minor street, Unicomio Street, can adequately see approaching westbound major street (Rancho Cortes) vehicles when they are approximately 250 feet east of the intersection. However, approaching vehicles from the west cannot be seen when they are 140 feet west of the intersection. A driver can observe a vehicle on Rancho Cortes at a point only 135 feet to the west on Rancho Cortes from Unicomio Street due to the vertical alignment of Rancho Cortes. The actual approach sight triangle distance available is slightly below the minimum required. Consequently, the 10-mile per hour safe approach speed criteria is not being met and a STOP sign can be considered for installation on Unicomio Street, the minor street. For one short time period, staff observed driver behavior on northbound Unicomio Street approaching Rancho Cortes to tum right or left. A total of 19 vehicles were noted during the observation period. It was found that of the 17 left-turning vehicles, 14 of these vehicles were considered "stopped" (slowed to a speed less than 10 mph). Of the two right-turning vehicles, one was considered "stopped" (slowed to a speed less than 10 mph). RECOMMENDATION: The Traffic Safety Coordinating Committee recommends installing a STOP sign on Unicomio Street at its intersection with Rancho Cortes. NECESSARY CITY COUNCIL ACTION: It will be necessary for the City Council to adopt an ordinance to establish the STOP sign, as recommended. Ull/Z1J/j!UU4 U8: U4 .FAJ1. 71SU4JIHt5' September 29, 2004 Lacli Hamer 2931 Rancho Cortes Carlsbad, CA 92009 Re: We need 2 stop sjgns! Dear Mr_ Johnson~ RECEIVED SEP 2 9 2004 ENGINli-ERING DEPARTMENT ( tm UU l I am writing you as a concerned citizen. There are tw<;, intersections in our neigJ1borhood that have no stop or yield signs and therefore are quite dangerous. Both are on a knoll, so visibility of oncoming traffic is poor. Without having to stop, motorists zip around these comers creating very dangerous situations that have been observed by a number of our neighbors. myself included. The two intersections in question are: JJ.ni~Rt-AiP.-.S,tr~~et..and..Ra,ncho,,,C,Q.tts>:.§, and Rancho Cortes and Carrillo Way. A second benefit of having stop signs at both of these intersections, is that it would slow down traffic on that stretch of Rancho Cortes, which has been another ongoing problem. - On behalf of our neighborhood, I would like to ask the City of Carlsbad to install stop signs at these intersec- tions, and thus creating a -safer neighborhood and preventing any future accidents. - I thank you for reviewing this request and look forward to a safer street Y7_::_ards ~er /760-438-1582 760-533-5692 PS: On an unrelated issue: a portion of the sidewalk on the east side ofUnicornio approaching Rancho Cor- tes is raised, creating a trip hazard. It also appears th.at that area has been used as a dump site for garden cJip-pings. ( LOCATION MAP CARRILLO RANCHO CORTES LEGEND: 0 PROPOSED STOP SIGN LOCATION NOT TO SCALE PROJECT NAME EXHIBIT PROPOSED STOP SIGN 1 .DRA~ BY: SCOTT EVANS, CARLSBAD ENGINEERING DEPT. 12 10 04 C: 1RAmC STOP SIGNS STOP SIGN-UNICORN/0-RANCHO CORTES1.DWG ( 140' REQUIRED (MAJOR STREET) RANCHO CORTES REQUIRED LINE OF SIGHT 135' ACTUAL i-: CJ) 0 ~ 0 (MINOR) ~ \STREET :::> 50' DECISION POINT NOT TO SCALE 155' RE VIREO TITLE (MAJOR STREET) RANCHO CORTES 50' i-: CJ) 0 § ~ (MINOR) :::::> \STREET 250' ACTUAL DECISION POINT UNICORNIO STREET I RANCHO CORTES INTERSECTION APPROACH SIGHT TRIANGLE DRAVtN BY: SCOTT EVANS, CARLSBAD ENGINEERING DEPT. 12 10 04 C: TRAFFIC STOP SIGNS STOP S/GN-UNICORN/0-RANCHO CORTES2.DWG NOT TO SCALE EXHIBIT 2