Although one of the three speed surveys at South Mission Road between Pepper Tree Lane and Green Canyon Road did not support recertifying the 50 mph speed limit for radar enforcement, the benefit of a consistent speed limit caused the county’s Traffic Advisory Committee (TAC) to make such a recommendation April 23.
The TAC’s recommendation is scheduled to be heard June 23 by the San Diego County Board of Supervisors, who can ratify, overturn or amend a TAC recommendation.
“I think continuity would be a consideration here,” said TAC secretary Kenton Jones. “One mile plus is a good healthy segment.”
In order for a speed limit to be enforceable by radar, a speed survey must show that the speed limit is within the closest 5 mph increment to the 85th percentile speed, although the speed limit can be reduced by 5 mph if findings of special circumstances not apparent to a typical motorist are made. Periodic recertification, along with a supporting speed survey, is required for continued radar enforcement.
The segment of South Mission Road under consideration covers 1.67 miles from 860 feet south of Pepper Tree Lane to Green Canyon Road. That portion of South Mission Road is classified as a Major Road on the county’s Circulation Element map.
The road is a four-lane roadway with a raised median north of Winter Haven Road and a two-lane roadway, with a two-way left turn lane at three segments, south of Winter Haven Road. Although the speed limit is 50 mph, its proximity to Fallbrook High School creates a school zone near the school which triggers a 25 mph speed limit when students are walking to or from school.
The speed limit on South Mission Road north of the reviewed segment is 35 mph while the speed limit south of Green Canyon Road is 50 mph.
A January 2009 traffic survey on Mission Road at Green Canyon Road indicated a two-way average daily traffic volume of 19,300 vehicles. An April 2004 traffic survey north of Big Oak Ranch Road produced a two-way average volume of 19,790 vehicles.
A November 2001 traffic survey taken north of Stage Coach Lane utilized a seven-day average volume, which was 10,960 southbound and 10,720 northbound vehicles.
In both 2001 and 2010 speed surveys were taken 1,630 feet south of Pepper Tree Lane with separate northbound and southbound data and 1,900 feet north of Green Canyon Road covering traffic in both directions. In the 2001 surveys 1,630 feet south of Pepper Tree Lane the 200 southbound vehicles had an 85th percentile speed of 53.7 mph with 67.5 percent of the vehicles in the 10 mph pace of 44-53 mph while the 197 northbound vehicles had an 85th percentile speed of 50.2 mph with 56.3 percent of drivers within a 41-50 mph pace.
The 2001 speed survey 1,900 feet north of Green Canyon Road consisted of 101 vehicles with an 85th percentile speed of 52.9 mph and 91 percent of drivers in a 46 to 55 mph pace.
The 2010 speed surveys 1,630 feet south of Pepper Tree Lane determined an 85th percentile speed of 48 mph for the 161 southbound vehicles with 77 percent of drivers in the 40-49 mph pace and an 85th percentile of 47 mph for the 151 northbound vehicles with 87.4 percent of drivers within the 40-49 mph pace.
The speed survey 1,900 feet north of Green Canyon Road had an 85th percentile speed of 60 mph with 57.4 percent of the 312 drivers traveling within a 10 mph pace of 47-56 mph.
In the 50-month period from January 1, 2005, to August 31, 2009, 97 collisions were reported on the 1.67-mile segment of South Mission Road. Those collisions included 44 in which injuries and/or fatalities were involved. The accident totals translate to a rate of 1.74 per million vehicle miles.
The statewide accident rate for similar two-lane roads with a speed limit at or under 55 mph is 1.32 per million vehicle miles while the statewide rate for divided four-lane roads is 0.90 per million vehicle miles. South Mission Road’s ratio of injury or fatality accidents to total collisions does not exceed the statewide average of approximately half of such collisions resulting in injuries or fatalities.
Because two of the three speed surveys supported retaining the 50 mph speed limit and raising the speed limit only for the portion north of Green Canyon Road would have created a 60 mph zone between two 50 mph zones, the TAC felt that a 50 mph speed limit should be applied to the entire segment for consistency.
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