TAC recommends retention of South Mission Road 35 mph speed limit

Joe Naiman

Village News Reporter

The Oct. 28 meeting of the county’s Traffic Advisory Committee included a recommendation to retain the 35 mph speed limit on South Mission Road from 860 feet south of Pepper Tree Lane to Hill Avenue.

The TAC also recommended that the 1.73-mile segment be recertified for radar enforcement. San Diego County Board of Supervisors approval will be required for the recertification, and a Feb. 8, 2023, Board of Supervisors hearing date has been targeted.

In order for a speed limit to be enforceable by radar, a speed survey must show that the speed limit is within an adjacent 5 mph increment to the 85th percentile speed. Periodic recertification, including a supporting speed survey, is required for continued radar enforcement and the county's Department of Public Works or a DPW contractor typically conducts speed surveys every seven years.

The speed limit may be rounded either up or down from the 85th percentile speed. The speed limit may also be rounded down an additional 5 mph if findings are made that the road has conditions which would not be apparent to a motorist unfamiliar with the road.

The mobility element of the county’s general plan classifies South Mission Road as a Major Road. South Mission Road, from 860 feet south of Pepper Tree Lane to Hill Avenue, is four-lane divided through highway with a pavement width ranging from 75 to 82 feet. The roadway is striped with a two-way left turn lane, lane striping, and intermittent parking lane and edge lines.

The signage along that part of South Mission Road includes school zone signage, signal ahead signs, pedestrian advisory signs, and school crossing signage. The road also has a flashing beacon to notify motorists about the school crossing at Elder Street. There are traffic signals at the intersections with Clemmens Lane, Ammunition Road, Aviation Road, Fallbrook Street, and Alvarado Street.

In 2008, a single speed survey was conducted 140 feet north of West College Street. The 85th percentile speed was 42 mph with 75.4% of drivers traveling within a 10 mph pace of 34-43 mph, and the TAC made findings of an accident rate higher than the statewide average, significant pedestrian traffic including school-related pedestrian activity, and driveway density to justify a 35 mph speed limit for radar enforcement.

The 2015 speed survey utilized three locations. The 85th percentile 250 feet south of Ammunition Road was 34.0 mph with 85% of motorists traveling within a 27-36 mph pace. The motorists 250 feet south of Old Stage Road had an 85th percentile of 42.0 mph with 81% of drivers within a 32-41 mph pace. The 85th percentile 300 feet south of Fallbrook Street was 40.0 mph with 76% of motorists driving within a 30-39 mph pace.

An October 2015 traffic survey taken 200 feet south of Fallbrook Street indicated 23,470 total vehicles consisting of 11,292 northbound and 12,178 southbound motorists. The 2022 estimated average daily volume was 25,480.

A total of 78 collisions, including 34 which involved injury, were reported on South Mission Road from 860 feet south of Pepper Tree Lane to Hill Avenue between June 1, 2019, and May 31, 2022. That creates an accident rate of 1.79 per million vehicle miles traveled. The statewide average for similar suburban divided four-lane roads with speed limits less than or equal to 55 mph is 1.25 per million vehicle miles.

Three speed surveys were taken on Oct. 12, 2022. The 201 drivers north of West College Street had an 85th percentile of 39.2 mph with 73% of motorists within a 10 mph pace of 29-38 mph. The 85th percentile for the 210 motorists in the speed survey 400 feet south of Clemmens Lane was 38.4 mph with 79% of drivers within a 30-39 mph pace. The speed zone 85th percentile was 38.8 mph with 76% of drivers within a pace of 30-39 mph.