TAC recommends radar-enforced 45 mph speed limit on West Lilac Road

The county's Traffic Advisory Committee has recommended that a 45 mph speed limit be posted on West Lilac Road and that the speed limit be certified for radar enforcement.

The TAC's unanimous March 13 recommendation will be considered by the San Diego County Board of Supervisors. The county supervisors are expected to approve an introduction and first reading of the ordinance May 13, which would allow for a second reading and adoption June 10 and an effective ordinance date of July 10.

"It's a nice speed," said county Department of Public Works traffic engineer Mike Kenney.

Although there is currently no posted speed limit, a motorist may be cited for exceeding the speed safe for conditions on any given portion of the road. "If they're going over 55 they'll still be cited," said Kevin Pearlstein, who represented the California Highway Patrol's El Cajon office at the March 13 TAC meeting.

The speed limit will cover the 4.4-mile distance from Camino Del Rey to Old Highway 395. No speed limit has ever been posted on the striped two-lane road which has two-way left turn pockets and varies in width from 26 to 40 feet, although the area around Sullivan Middle School (which now includes Bonsall High School) has an automatic school zone speed limit of 25 mph.

The road also has a seven-ton weight limit for trucks or other vehicles not traveling to a destination along the road. West Lilac Road is classified as a Light Collector on the Mobility Element of the county's general plan.

A pair of October 2014 traffic surveys revealed a two-way average daily volume of 2,330 vehicles east of Camino Del Cielo and a westbound average daily volume of 2,125 vehicles west of Old Highway 395. The previous traffic survey was taken in April 2002 and resulted in two-way average daily volumes of 1,890 vehicles east of Camino Del Cielo and 1,610 vehicles west of Old Highway 395. The 21 reported collisions along the roadway during the 70-month period from Jan. 1, 2009, to Oct. 31, 2014, included nine which involved injuries.

A school zone speed limit can be enforced by radar without a supporting speed survey, but for a non-automatic speed limit to be certified for radar enforcement a speed survey must show that the speed limit is within an adjacent 5 mph increment to the 85th percentile speed. The speed surveys cannot be taken at curves where advisory speeds are posted. "This road has a characteristic of at least half of its alignment controlled by curves," said TAC secretary Kenton Jones.

Most of the collisions took place within the curves, including some in which the driver was exceeding the speed which was safe for conditions. "Exceeding safe speed of 50 mph through the curves is not at all advisable," Jones said.

(Some of the curves have advisory speeds of 35 mph.)

A speed survey was also taken in 2002 during a review of the road. "In the establishment of the speed limit we are looking at the free flow on straight portions of the road," Jones said.

In the 2002 speed survey taken 300 feet west of Via Ararat Drive, the 85th percentile speed was 44.3 mph with 86.6 percent of drivers traveling within a 10 mph pace of 37-46 mph. A second speed survey was taken 200 feet west of Camino Del Cielo which indicated an 85th percentile speed of 48.8 mph with 70.7 percent of the drivers within a 39-48 mph pace.

Formal speed limits are generally not posted on roads with traffic under 2,000 vehicles per day, which was the case in 2002. The 2015 traffic volume exceeding 2,000 vehicles led to the decision to formalize a speed limit. "I don't think that's going back down," Jones said.

TAC staff member Tricia Horsman oversaw two Feb. 24, 2015, speed surveys. The speed survey 300 feet west of Via Ararat included 113 vehicles which crossed that location between 9:55 a.m. and 11:40 a.m. The 85th percentile speed was 47.9 mph with 72 drivers, or 64 percent, traveling within a 39-48 mph pace. The most common speed, with 11 drivers, was 42 mph, while nine drivers passed the location at 39 mph. The fastest motorists were one driver apiece at 55 mph and 54 mph and seven drivers at 53 mph while the slowest motorists consisted of two drivers traveling 28 mph and two at 32 mph. The average speed was 42.8 mph.

The speed survey 200 feet west of Camino del Cielo was taken between noon and 1:15 p.m. and also included 113 drivers. The 85th percentile speed was 46.7 mph with 78 drivers, or 69.0 percent, within the pace of 37-46 mph. The most common speeds were 44 mph with 14 motorists, 43 mph with 13 drivers, and 42 mph with 10 vehicles, and the average speed was 42.0 mph. A driver at 57 mph was the fastest, although the next-highest speed was from one driver at 53 mph. One driver made 28 mph the lowest speed while three vehicles traveled at 30 mph.

The Department of Public Works has the discretion of where to post speed limit signs; normally those are posted at one-mile increments. "That doesn't always match nicely to where the curves are and where the schools are," Jones said. "We would generally bypass the curve and then place the speed limit at the first opportunity outside the curve."

Jones added that DPW also seeks to post signs after major intersections so that drivers turning onto a road can be made aware of that road's speed limit.