SAN DIEGO (KGTV) - According to Caltrans, about 37 people on average are killed in wrong-way collisions each year on California's highways.
Just a few years ago, San Diego was one of the deadliest places in the state for wrong-way crashes.
Things got so bad in 2015, California lawmakers got involved and Caltrans developed a pilot program to prevent deadly collisions.
In a 2016 interview, a Caltrans spokesperson said, "Along Interstate 15 they will have 60 offramps that will be augmented with additional signage as well as visual cues for people who may make that wrong turn."
During the three-year pilot program, Caltrans installed and tested different ways to deter wrong-way drivers along exit ramps in Sacramento and San Diego.
The state department installed two-way reflective pavement markers that show white or yellow to right way drivers, and red to wrong-way drivers
They also installed "wrong way" signs at the offramps, "do not enter" signs equipped with LED lights flashing 24 hours a day, and had active monitoring systems that use radar to detect wrong-way drivers.
"We found that the two-way reflective markers were the most effective at deterring wrong-way drivers, so before the study was even over, we started installing those along the state highway system," Caltrans spokesperson Kerstin Tomlinson.
According to Caltrans, in San Diego, the number of wrong-way drivers decreased by 44% after the reflectors were installed.
The department said the flashing LED signs showed promise at preventing wrong-way collisions and Caltrans will continue to monitor their impact to determine whether to expand use at exit ramps across the state.
ABC 10News asked Caltrans if additional wrong-way preventions were installed in the area near Friday's crash.
A spokesperson says, "Plans are underway to install wrong-way driver countermeasures on three exit ramps along Interstate 5 between San Diego and the border, including the location of Friday's crash. No timelines have been set at this point."
We still don't know how or where the wrong-way driver got on the freeway.
Along with the pilot program updates, Caltrans said last fall they also became the first department of transportation in the country to receive federal approval to launch a pilot program for new markings at the entrance of 30 offramps in the San Diego area.
"We're using this two-way paint that's similar to the two-way reflectors, and we're painting Do Not Enter at the beginning of the ramp and also arrows pointing in the correct direction, Tomlinson said.