Alturas Road speed limit lowered

Joe Naiman

Village News Reporter

The speed limit on Alturas Road south of Fallbrook Street will be reduced.

A 4-0 San Diego County Board of Supervisors vote March 2, with Joel Anderson absent, approved the first reading and introduction of the ordinance to lower the speed limit from 35 mph to 30 mph. A 5-0 Board of Supervisors vote March 16 approved the second reading and adoption. The ordinance will become effective April 15, although the county’s Department of Public Works may erect signage before that date.

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 DPW or a 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.

If speed surveys are taken at more than one location along a reviewed segment a "speed zone" for the entirety of the speed surveys can be used. The accident rate on Alturas Road south of Fallbrook Street is more than four times the statewide average, and Oct. 22 the county’s Traffic Advisory Committee unanimously recommended a reduction of the Alturas Road speed limit due to the high accident rate.

Alturas Road from Fallbrook Street to the end south of Ali Way measures 1.20 miles. The striped two-lane roadway has a solid double yellow centerline which prohibits passing and intermittent white edge lines. It is not classified on the mobility element of the county's general plan. The pavement width ranges from 20 to 40 feet. A traffic signal exists at the intersection of Alturas Road and Ammunition Road. The 35 mph speed limit had previously been certified for radar.

Alturas Road has a significant number of multi-family residential units. Clemmens Lane Park and a shopping center are close to Alturas Road, so many residents of that street walk to those amenities. Many motorists utilize Alturas Road, including intersections, to commute. The east gate of Camp Pendleton is on Ammunition Road near the intersection of Alturas Road.

An October 2020 traffic survey taken 900 feet south of Clemmens Lane produced an average daily volume of 2,753 vehicles consisting of 1,388 southbound drivers and 1,365 northbound motorists. A May 2021 traffic survey 190 feet north of Alturas Lane had a volume of 4,436 drivers with 2,545 traveling northbound and 1,891 driving southbound.

Traffic surveys were taken, May 27, 2021, 190 feet north of Alturas Lane and 900 feet south of Clemmens Lane. The 151 drivers in the speed survey 190 feet north of Alturas Lane had an 85th percentile of 36.1 mph with 76% within a 10 mph pace of 28-37 mph. The speed survey 900 feet south of Clemmens Lane measured 228 drivers with an 85th percentile of 37.1 mph and 71% of drivers in a 26-35 mph pace. The 85th percentile for the speed zone was 36.6 mph with 73.5% of the drivers within a 27-36 mph pace. Only 17 of the 379 drivers in the speed survey were traveling 6 mph or more above the existing 35 mph speed limit.

During the 36-month period from June 1, 2018, to May 31, 2021, Alturas Road between Fallbrook Street and the end had 23 reported collisions including three in which an injury occurred. The collision rate is 6.51 per million vehicle miles. The statewide average for similar suburban two-lane roads with speed limits under 45 mph is 1.60 per million vehicle miles.

Improper turning caused six of the collisions. Right of way violations were responsible for five collisions. On three occasions, a motorist ran the traffic signal at the intersection of Alturas Road and Ammunition Road, which accounted for seven of the total collisions. Two collisions apiece were caused by driving under the influence, unsafe speed, and driving on the wrong side of the road. Unsafe starting or backing caused one collision. The cause of two collisions was not determined.