Supervisors support Sandia Creek Drive weight limit

The public road portion of Sandia Creek Drive in San Diego County will soon have a 7-ton weight limit.

A 5-0 San Diego County Board of Supervisors vote, Wednesday, Sept. 30, approved the first reading and introduction of the weight limit ordinance. A second reading and adoption is scheduled for Oct. 14, in which case the weight limit would become enforceable Nov. 13 although the county’s Department of Public Works could install signage before the effective date of the ordinance.

A weight limit must include an alternate truck route, and East Mission Road to Interstate 15 was specified as that alternate route. The weight limit will apply only to through traffic and not to any truck traffic making deliveries to or from properties along Sandia Creek Drive.

Sandia Creek Drive between De Luz Road and the end of the county-maintained portion of the road measures 2.61 miles. The striped two-lane roadway has a width of 25 feet. There is no posted speed limit on Sandia Creek Drive, which creates a legal speed limit of 55 mph, and curves in the road are preceded by advisory signs which recommend limiting speed to 30 mph or 25 mph.

The mobility element of the county’s general plan classifies Sandia Creek Drive as a minor collector, which is intended primarily for residential neighborhoods or rural areas with steep slopes and physical constraints.

Traffic surveys were taken 3,000 feet north of Rock Mountain Drive on two consecutive days in August 2019. Aug. 13 was a Tuesday, and the 1,830 vehicles consisted of 1,345 northbound and 485 southbound motorists. The heaviest hourly traffic was between 4-5 p.m. when 437 drivers were counted, and the 168 drivers between 6-7 a.m. made that hour the busiest for that morning.

On Wednesday, Aug. 14, 1,380 northbound and 429 southbound vehicles created equaled 1,809 drivers with 427 of those drivers traveling between 4-5 p.m. and 122 motorists making 6-7 a.m. the busiest morning hour.

The Aug. 13 traffic consisted of 1,740 passenger cars, 45 single-unit vehicles with two axles and four tires, 29 motorcycles, eight three-axle single units, four buses, three single units with two axles and six tires and one single unit with more than four axles.

The Aug. 14 survey counted 1,706 passenger cars, 50 single-unit vehicles with two axles and four tires, 35 motorcycles, 10 three-axle single units, four buses, three single units with two axles and six tires and one single trailer vehicle with no more than four axles.

The collision data only includes reported collisions on the public portion of the roadway and covered the period from Jan. 1, 2017, to Dec. 31, 2019. The 13 reported collisions on the public road during those 36 months provided a collision rate of 2.51 per million vehicle miles.

The statewide average for similar rural one-lane or two-lane conventional rolling roads with speed limits less than or equal to 55 mph is 1.26 collisions per million vehicle miles. Because the collision data is for the public road portion only it does not include the May 21 fatal accident involving a truck driver who lost control of his vehicle on the private road section of Sandia Creek Drive.

The public road section of Sandia Creek Drive has few driveways, but the private road portion accesses more homes. The properties on the private section of the road do not have a homeowners' association, and volunteers in conjunction with a road maintenance agreement optimize the condition of Sandia Creek Drive. The bridge on the public road section was intended for residents rather than through traffic.

Trucks are believed to be taking Sandia Creek Drive rather than East Mission Road and Interstate 15 to avoid the scale on the freeway, to avoid traffic congestion along Interstate 15, and because global positioning systems may indicate shorter mileage totals by taking the shortcut through De Luz rather than the major roads.

The weight limit will apply only to the publicly maintained road. The privately maintained road had signs stipulating an 8-ton weight limit, and those signs were changed this summer to reduce the weight limit to 7 tons.

Sandia Creek Drive also has a Riverside County portion which is administered by the De Luz Community Services District. That entity installed a 7-ton weight limit sign on Sandia Creek Drive in September while also installing a notice of the weight limit on Rancho California Road so that trucks from Murrieta will take an alternate route.

On June 12, the county’s Traffic Advisory Committee unanimously recommended the 7-ton weight limit.

Joe Naiman can be reached by email at [email protected].