Currently the speed limit on Old Castle Road is 50 mph for the 0.64- mile segment from Champagne Boulevard to 3,400 feet east of Champagne Boulevard and 45 mph for the 0.6-mile portion from 3,400 feet east of Champagne Boulevard to 550 feet east of Mile Post 6. If the San Diego County Board of Supervisors ratifies the October 23 recommendations of the county’s Traffic Advisory Committee, the speed limit will be 45 mph for the entire portion of the road.
The county supervisors are scheduled to consider a first reading and adoption of the ordinance for a consistent speed limit on January 6, 2016. If the Board of Supervisors approves the introduction and first reading that day the second reading and adoption would likely take place January 27 and the new speed limit would take effect February 26.
The 45 mph speed limit for both segments would be certified for radar enforcement; the 45 mph speed limit on the eastern segment is currently certified for radar while the 50 mph speed limit for the western segment does not have radar certification.
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.
In the case of the October 23 unanimous TAC recommendation, the findings invoked the advantage of a consistent speed limit throughout the entire 1.24-mile segment. When the speed limit is next considered for recertification the two portions reviewed October 23 will be considered as a single segment, although speed surveys will likely be taken at both historical locations.
Old Castle Road is a two-lane roadway with both median striping and edge striping on both sides. It varies in width between 26 and 41 feet and is classified as a Light Collector in the mobility element of the county’s general plan. The portion from 3,400 feet east of Champagne Boulevard to 550 feet east of Mile Post 6 includes a traffic calming area identified by flashing yellow beacons and special identifying signs.
A July 2015 traffic survey taken 150 feet east of Costalota Road indicated a two-day average daily volume of 7,130 vehicles. The previous traffic survey on Old Castle Road was taken in May 2004 east of Old Castle Place and resulted in an average daily volume of 8,100 vehicles.
In 2008, both the speed survey 300 feet east of Indian Hill Place and the speed survey 400 feet west of Costalota Road produced an 85th percentile speed of 44.0 mph with 66.0 percent of the drivers traveling within a 10 mph pace of 36-45 mph. On November 7, 2014, National Data and Surveying Services conducted a speed survey 400 feet west of Costalota Road between 11:30 a.m. and 1:30 p.m.
The 424 vehicles in that survey had an 85th percentile speed of 53.0 mph with 72.0 percent of motorists traveling within a 44-53 mph pace. On October 7, 2015, TAC staff member Tricia Horsman conducted a speed survey 300 feet east of Indian Hill Place between 10:10 a.m. and 11:00 a.m.; that survey included 131 vehicles with an 85th percentile of 50.9 mph and 75.0 percent of drivers within a 42-51 mph pace. The 50th percentile in the 2014 speed survey 400 feet west of Costalota Road was 47 mph while the median for the 2015 speed survey 300 feet east of Indian Hill Place was 46.6 mph.