Old Highway 395 and Rainbow Glen Road placed on Traffic Signal Priority List

The intersection of Old Highway 395 and Rainbow Glen Road has been placed on the San Diego County’s Traffic Signal Priority List.

A 5-0 board of supervisors vote, Wednesday, Nov. 20, placed the intersection on the Traffic Signal Priority List. Normally priority points rather than the length of time an intersection has been on the list will determine the next intersection to be signalized once funding permits, but design readiness issues may allow a lower-ranked intersection to be signalized first as can grant funding for a specific intersection.

The county’s Department of Public Works has identified a funding source from the county’s road fund to allow the Rainbow signal to be installed sooner, and DPW traffic engineering manager Murali Pasumarthi is targeting the Dec. 11 board of supervisors’ meeting for the county supervisors to authorize the advertisement for bid and subsequent award of a construction contract for the signal.

“We’re hoping to get this design done by early fall,” Pasumarthi said.

The intersection meets both the four-hour vehicular volume warrant and the peak hour volume warrant for a traffic signal. The intersection fell one collision short of the collision warrant for a traffic signal which requires five collisions correctable by a signal within a one-year period, but just those four collisions between June 1, 2017, and May 31, 2018, created an accident rate more than four times the statewide average for similar intersections. Two of those collisions involved injury, and after a July 23 collision resulted in one fatality along with three injuries, DPW reviewed the intersection to determine if a signal would increase the safety of motorists and pedestrians.

“It has been an ongoing concern to the residents,” Supervisor Jim Desmond said.

Because there was no opposition at the board of supervisors’ meeting, there was no need for the Rainbow residents to speak, but six of them submitted speaker slips in favor.

The mobility element of the county’s general plan classifies Old Highway 395 as a community collector and Rainbow Glen Road as a light collector. Both roads have 24 feet of travel width and a solid double yellow centerline which prohibits passing. Old Highway 395 has a 55 mph speed limit while Rainbow Glen Road has a 45 mph speed limit with stop signs at Old Highway 395 in both directions.

The Oak Crest Estates mobile home park is located on Oak Crest Road, which is off Rainbow Glen Road, and other streets are also off Rainbow Glen Road, but no street west of Old Highway 395 other than Rainbow Glen Road provides access to the former United States highway in that area.

DPW used a July 17, 2018, traffic survey which produced an average daily volume of 5,881 northbound vehicles on Old Highway 395 south of Rainbow Glen Road, 2,311 southbound motorists on Old Highway 395 north of Rainbow Glen Road, 1,386 eastbound vehicles on Rainbow Glen Road west of Old Highway 395 and 1,101 westbound vehicles on Rainbow Glen Road east of Old Highway 395.

An August 2010 traffic survey resulted in an average daily volume of 3,537 northbound, 1,492 southbound, 1,186 eastbound and 2,012 westbound vehicles. The November 2006 traffic survey indicated an average daily volume of 3,320 northbound, 2,231 southbound, 673 eastbound and 1,092 westbound motorists.

Rainbow residents and DPW staff members both cite increasing commuter traffic to Riverside County rather than Rainbow residents as the cause for the increased traffic volume, and the use of Old Highway 395 rather than Interstate 15 is even more prevalent when an accident causes delays on I-15.

Between 5-6 p.m. July 17, 2018, the intersection had 1,256 northbound, 111 southbound, 91 eastbound and 57 westbound vehicles. The volume between 4-5 p.m. was 1,175 northbound, 123 southbound, 131 eastbound and 55 westbound vehicles. The intersection had 766 northbound, 113 southbound, 109 eastbound and 81 westbound vehicles between 3-4 p.m. Between 6-7 a.m. 124 northbound, 422 southbound, 151 eastbound and 89 westbound vehicles entered the intersection. At least 100 southbound vehicles entered the intersection during every 15-minute period between 5:45-6:45 a.m. Northbound traffic exceeded 100 vehicles for every 15-minute period between 2:45-7 p.m.

The fatal traffic collision took place at 4:42 p.m., July 23. A driver trying to enter Old Highway 395 from Rainbow Glen Road was broadsided by a vehicle driving on Old Highway 395. That collision was caused by a right of way violation, as were four collisions during the one-year period. Two of those were during peak morning hours, including one which resulted in one injury, and the other two were during peak evening hours including one which resulted in three injuries.

Those four collisions alone created a rate of 1.03 collisions per 1 million vehicles entering the intersection. The statewide average for four-way rural intersections with a stop control on one road is 0.22. Because DPW was evaluating a traffic signal, only the collisions correctable by a traffic signal rather than all collisions are included.

The county’s Traffic Advisory Committee unanimously recommended that the intersection be placed on the Traffic Signal Priority List during the Oct. 25 TAC meeting.