In 2002, there were 24 fatalities on Interstate 70 as a result of cross-median crashes. I-70, one of the oldest interstates in the country built between 1956 and 1965, was constructed with 40-foot medians instead of the standard 60-foot medians today.
To attempt to rectify the situation in the most cost-effective manner, MoDOT began installing median guard cable – strands of steel cable. When the cable is struck, the posts yield and the cable deflects up to 12 feet, effectively catching and decelerating the vehicle and keeping it in the median. Internal studies have shown that the cable catches 95 percent of vehicles entering the median and keeps the vehicles from entering the opposing lanes. Median guard cable is designed to stop passenger cars and light trucks. It is not designed to stop large trucks, but there are many documented cases where it has.
After installation of 179 miles of median guard cable on I-70, in 2006 there were two cross-median fatalities – a 92 percent decrease. Similarly, there were 25 crossover deaths on I-44 in 2006. In 2008, after guard cable, that number dropped to zero.
MoDOT has now installed more than 800 miles of guard cable on divided Missouri highways at a cost of $90-100 million. MoDOT estimates that guard cable has saved more than 500 lives in Missouri since 2002.