TAC delays South Mission Road speed limit recommendation

South Mission Road from 860 feet south of Pepper Tree Lane to Green Canyon Road is a segment of 2.05 miles, but the road has different characteristics.

The speed limit for the entire segment is 50 mph and that speed limit can be enforced by radar, but the county’s Traffic Advisory Committee has called for speed studies on separate segments before any recommendation is made to recertify a speed limit for radar enforcement.

“They’d rather look at it as two one-mile-long segments,” said TAC secretary Kenton Jones.

The lack of a recommendation at the March 10 TAC meeting could allow for different speed limits for the separate segments. 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.

South Mission Road is a striped four-lane roadway with a raised planted median between 860 feet south of Pepper Tree Lane and Winter Haven Road and is primarily a striped two-lane roadway, including three segments with a two-way left turn lane, between Winter Haven Road and Green Canyon Road.

Bicycle lanes are along both sides of the road. South Mission Road is classified as a Major Road in the Mobility Element of the county’s general plan. Fallbrook High School and Ivy High School are on the east side of the road between Stage Coach Lane and Winter Haven Road, which creates a 25 mph speed zone when children are present.

The TAC felt that the different road characteristics north of Winter Haven Road and south of Winter Haven Road merited possible separate speed limits. The TAC seeks to avoid short speed limit segments (other than school zones or other automatic speed limit zones), but the approximate one-mile length of each segment allows for the possibility of different speed limits. “They’re long enough,” Jones said.

An April 2016 traffic survey at Green Canyon Road revealed a two-way average daily volume of 21,532 vehicles on Mission Road. The San Diego County Board of Supervisors placed that intersection on the county’s Traffic Signal Priority List in January and volume warrants were based on an October 2014 traffic survey indicating an average daily volume of 21,960 vehicles approaching that three-way intersection including 20,800 along Mission Road as well as 1,160 westbound vehicles on Green Canyon Road.

A January 2009 traffic survey of Mission Road at Green Canyon Road revealed an average daily volume of 19,300 vehicles.  During the 62-month period between Jan. 1, 2011, and Feb. 29, 2016, 80 vehicle collisions were reported on the 2.05-mile segment including 37 which involved injury and one with a fatality.

In 2010 a speed survey 1,900 feet north of Green Canyon Road indicated an 85th percentile speed of 60 mph with 57.4 percent of the drivers traveling within a 10 mph pace of 47-56 mph and a speed survey 1,630 feet south of Pepper Tree Lane resulted in an 85th percentile of 47 mph with 87.4 percent of the drivers within a pace of 40-49 mph.

The speed limit south of Green Canyon Road is 50 mph, and in 2010 the TAC suggested a 50 mph speed limit for the entire segment to provide consistency rather than a 60 mph segment between two 50 mph segments.

The 2016 speed survey utilized a Jan. 8 survey 300 feet north of Sterling Bridge and April 21 surveys 1,900 feet north of Green Canyon Road and at the northern end of the speed zone 860 feet south of Pepper Tree Lane.

The speed survey 300 feet north of Sterling Bridge was taken between 9:15 a.m. and 11:15 a.m. and produced an 85th percentile of 54.0 mph with 88.0 percent of the 201 drivers within a 45-54 mph pace.

The most frequent speed was 48 mph with 26 drivers while 25 motorists apiece crossed the speed survey point at 49 mph and 51 mph and 23 vehicles were traveling at 50 mph. The fastest drivers were one apiece at 62 mph, 60 mph, and 59 mph while the slowest motorist was driving at 43 mph.

The speed survey 860 feet south of Pepper Tree Lane was taken between 9:40 a.m. and 11:40 a.m. and measured 406 vehicles with an 85th percentile speed of 53.8 mph and 85 percent of the drivers within a 46-55 mph pace.  The most common speeds were 50 mph with 46 motorists, 51 mph with 45 drivers, and 49 mph with 44 vehicles. A driver at 63 mph was the fastest motorist and the slowest vehicle was traveling at 43 mph.

The speed survey 1,900 feet north of Green Canyon Road was also
conducted between 9:40 a.m. and 11:40 a.m. The 177 vehicles had an 85th percentile speed of 56 mph with 82 percent of drivers within a 46-55 mph pace.  The 23 motorists at 50 mph made that the most common speed followed by 20 vehicles at 51 mph and 18 drivers at 53 mph. One motorist at 63 mph was the fastest while the two slowest vehicles traveled at 44 mph.

The next TAC meeting is scheduled for April 28. “If the data’s ready it will be at the very next one,” Jones said.

If the TAC does not have the appropriate data in time for the April 28 meeting, the speed limit review will occur at a future TAC meeting.

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