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HomeMy WebLinkAbout2012-05-07; Traffic Safety Commission; ; Investigate the need to establish a STOP on Camino Alvaro at its intersection with Sombrosa Street.CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: May 7, 2012 LOCATION: INITIATED BY: Intersection of Camino Alvaro and Sombrosa Street Tracy Michael ITEMNO.6A REQUESTED ACTION: Investigate the need to establish a STOP on Camino Alvaro at its intersection with Sombrosa Street. BACKGROUND: Camino Alvaro intersects Sombrosa Street in a T-intersection configuration in a residential neighborhood with Camino Alvaro being considered the "stem" of the T- intersection. Sombrosa Street is considered the "top" of the T (see Exhibit 1). Currently this intersection is uncontrolled on all approaches. DATA: Camino Alvaro and Sombrosa Street are located in the southeast portion of the city. Both streets are unclassified on the Circulation Element of the General Plan but function as local streets based on street width and adjacent land uses. These streets serve a residential neighborhood comprised of single family homes. Camino Alvaro provides access to and from Rancho Santa Fe Road/Olivenhain Road for the neighborhood. Camino Alvaro and Sombrosa Street both have a curb to curb width of 40 feet, are fully improved with curb, gutter, sidewalk and street lights on both sides of the streets. On- street parking is allowed on both sides of Camino Alvaro and Sombrosa Street. A 24- hour intersection approach count was conducted on March 13, 2012 the results of which are shown on Table A. Page I CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: ( continued) May 7, 2012 Time Northbound 0000-0100 2 0I00-0200 0 0200-0300 1 0300-0400 0 0400-0500 0 0500-0600 2 0600-0700 10 0700-0800 51 0800-0900 31 0900-1000 18 1000-1100 25 1100-1200 27 1200-1300 40 1300-1400 29 1400-1500 63 1500-1600 45 1600-1700 42 1700-1800 47 1800-1900 45 1900-2000 24 2000-2100 14 2100-2200 7 2200-2300 5 2300-2400 l Totals 529 Table A Camino Alvaro and Sombrosa Street 24~Hour Intersection Approach Volumes at Camino Alvaro Sombrosa Street n/a Subtotal Southbound Eastbound 2 0 0 0 0 0 1 1 0 0 0 0 0 7 0 2 5 4 IQ 19 10 51 60 50 31 40 36 18 27 27 25 15 21 27 23 27 40 30 32 29 35 25 63 34 36 45 37 58 42 32 54 47 40 37 45 37 37 24 20 17 14 11 13 7 13 7 5 7 4 1 0 0 529 493 495 ITEM NO. 6A Total -Subtotal Volume 0 2 0 0 1 2 0 0 7 7 9 t1 29 39 l JO 161 76 107 54 72 36 61 50 77 62 102 60 89 70 133 95 140 86 128 77 124 74 119 37 61 24 38 20 27 11 16 0 1 988 1517 In the past three years, there have been no reported collisions at the subject intersection. Each stop sign request received by staff is analyzed based on standards and guidelines found in the California Manual on Uniform Traffic Control Devices (MUTCD) and the Caltrans Highway Design Manual. Stop signs, if improperly used, can cause substantial inconvenience to drivers and should be used only where warranted. One of the conditions that may warrant consideration of installing a stop sign on the minor street is when the safe approach speed to the intersection is less than 10 miles per hour, which is a result of restricted visibility for the driver. 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. For the purpose of this report, Camino Alvaro will be considered the minor street as the stem of the T-intersection. Sombrosa Street will be considered the major street as the top of the T-intersection. As drivers approach an uncontrolled intersection, they have right-of-way assignment based upon the rules of the road. However, the driver should have an unobstructed view of the entire intersection and sufficient distance along the line of sight at the intersecting street for the driver to anticipate and avoid conflicts with approaching vehicles. When a driver on the minor street is traveling towards the major street, a decision point is required to determine whether braking to a stop is necessary because of an approaching Page2 r CITY OF CARLSBAD TRAFFIC SAFETY COMMISSION STAFF REPORT COMMISSION MEETING OF: ( continued) May 7, 2012 ITEMNO.6A vehicle on the major street. This decision point location on the minor street must allow the driver sufficient distance to view to both the right and left the approaches on the major street. The driver on the minor street, generally not having the right-of-way, can then initiate actions to slow, stop, or avoid a conflict with other vehicles, as necessary, when sufficient corner sight distance is provided (see Exhibit 2). For the analyses of local streets, the minor street decision point is assumed to be 50 feet from the intersection given the vehicle on the minor street has an approach speed of 10 miles per hour. A distance of 150 feet (stopping sight distance for 25 miles per hour) along the major street must be provided to minor street drivers to view vehicles approaching the intersection. At the study intersection, sight distance from Camino Alvaro looking to the west was measured to be 116 feet, which is Jess than the required 150 feet. The sight distance limitation is due to the horizontal curvature of Sombrosa Street and a large Juniper shrub growing on private property. Sight distance looking to the east was found to be 3 50 feet, which exceeds the 150 foot minimum requirement. Vehicles parked on the west side of the intersection on the south side of Sombrosa Street could further reduce the sight distance looking to the west. Based on the study results, staff finds that the 10-mile per hour safe approach speed criteria is not being met for northbound Camino Alvaro drivers and a stop sign can be considered for installation on Camino Alvaro at Sombrosa Street. RECOMMENDATION: Based on the findings contained in this report, the Traffic Safety Coordinating Committee recommends the installation of a stop sign on Camino Alvaro at its intersection with Sombrosa Street. This would include painting a limit line and a "STOP" legend on the roadway. NECESSARY CITY COUNCIL ACTION: The City Council must adopt an ordinance to establish the STOP control as recommended. Page 3 Location Map Proposed STOP on Camino Alvaro At Sombrosa Street Exhibit 1 ,------------------------- REQUIRED LINE OF SIGHT SOMBROSA STREET CONFLICT POINT 150' REQUIRED 116' MEASURED MEASURED LINE OF SIGHT DECISION POINT 350' MEASURED 150' REQUIRED REQUIRED ,,,.,,,. ~,,,. ,,,. ,,,. ,,,. ,,,. ,,,. ,,,. --- ,;' _,,,,,,,. ---- ......... ::---------- DECISION POINT _.. --- MEASURED LINE OF SIGHT ~ I vh ! .E NOT TO SCALE DATE or MEASUREMENTS: 2/29/12 ~ ~---------------------------------..---...... ~ CAMINO ALVARO AT SOMBROSA STREET SIGHT DISTANCE ANALYSIS EXHIBIT 2 ~ t li ~ _____________________________________ ..