Cable barriers in interstate medians reduce crash danger, but can't eliminate it entirely
In the last few years, Illinois spent $10 million to install a high-tension cable barrier system on Interstate 74 between Champaign and Danville. The goal: to reduce the number of fatalities and serious injury accidents caused when vehicles cross the median and veer into oncoming traffic.
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But state officials and the system's manufacturer warn that even the special barriers aren't foolproof, as evidenced last weekend during a three-car accident that killed a Catlin woman.
"There's no barrier that we can put on the highway that can prevent all crashes," said Master Sgt. Shad Edwards, the daytime patrol commander for the Illinois State Police's District 10 region. "You're still going to have people who are going to crash. That's why you still have to have drivers who are qualified and observant and prepared to travel in winter weather conditions."
The crash, which killed 33-year-old Kristy L. Etchison, occurred at 3:44 p.m. Saturday on the snow- and ice-covered interstate, about five miles east of Urbana.
According to a report, 35-year-old Bidemi O. Ajobiewe, of Champaign, was driving a 2012 box truck west on the interstate near milepost 189 when he lost control of the vehicle, crossed the median and struck an oncoming van. He was ticketed for improper lane usage, failure to reduce speed to avoid an accident, and not having a valid classification of driver's license.
"The box truck went through the cables ... and the back end of the truck made contact with the front end of the van," Edwards recited from the report.
Benjamin Knight, 37, of Catlin — the van's driver — and Ms. Etchison, his passenger, were trapped in the wreckage. Ms. Etchison was pronounced dead at the scene, while Knight was taken to Carle Foundation Hospital, where he was listed in good condition Thursday.
The Illinois Department of Transportation began installing high-tension cable barrier systems in 2005, and currently has nearly 300 miles of cable in place, according to state safety engineer Priscilla Tobias.
By installing the system, the department has "nearly eliminated median crossover crashes," Tobias said. Each year, based on safety analysis and new policies, she added, IDOT continues to identify and install additional miles of the system "as a means to improve the safety performance on Illinois interstates and freeways."
She pointed to other benefits of the system: No major road reconstruction is required; it's relatively easy to install and repair; it minimizes potential for snow drift; it's still functional after typical hits; and it's "a forgiving impact system in that it does not place high deceleration forces" on vehicle occupants.
The state installed cable in the I-74 median between Champaign and Danville during four separate projects between 2011 and 2013, Tobias said. She said the barriers were added after a statewide analysis identified the area as a priority corridor, based on its high traffic volume, narrow median width and cross-over crash history.
That corridor, while relatively flat, has "an extremely" narrow median separating the two eastbound and westbound lanes, Edwards said.
"Unlike other grassy medians in the state, it doesn't provide any amount of time or stopping distance for a vehicle that crosses it," said Edwards, who in his 25 years with the state police has seen the result too many times. "That vehicle, in a split second, has already traveled into the other lanes and is looking at a head-on collision with a vehicle coming from the other direction. It's a perfect example of why and where you need some enhanced lane dividers, whether they be cable barriers or concrete guard rails."
This particular system — of four galvanized wire-rope cables, measuring 20 inches to 39 inches from the ground, with posts placed every 15 feet — was manufactured by Gibraltar Cable Barrier Systems. The Texas-based firm is one of five in the United States that makes high-tension cable barrier systems. Gibraltar has a 50 percent share of the market and has provided more than 15 million linear feet in the U.S. and Canada, including more than 770,000 linear feet in Illinois, general manager Ron Faulkenberry said.
"It's the most robust system that we have," Faulkenberry said of the system along I-74.
In ideal test conditions, he said, the system has proven it can stop and redirect an 18,000-pound truck that hits the cables at a 15-degree angle while going about 50 mph.
"The systems are about 98 percent effective, which is better than any other system that you have out there — guard rails or concrete barriers," Faulkenberry said.
He pointed to a fiery semi-tractor trailer crash last weekend on Interstate 65 in Indiana. The crash, which was also weather-related, involved more than 20 vehicles. But none crossed the median, and an Indiana Department of Transportation official attributed that to the cable barrier system the state installed in 2010.
"Unfortunately, it's not 100 percent effective," Faulkenberry said. "There are just so many variables. You get a box truck that's fully loaded that goes in (to the median) at a steeper angle, there's basically no timeout after that. It's terribly unfortunate. Our thoughts and prayers are with the family."
While the system has been "very effective" in reducing median cross-over crashes in Illinois, it isn't infallible, Tobias said.
"The cable barrier has nearly eliminated median cross-over crashes," she said. "But angle and speed and the type of vehicle all play factors in the performance of the roadside barriers. Cable rail, as well as concrete barrier and the steel-plate beam guardrail, are not designed for semis, although we have contained them on occasion. Each system has its benefits and disadvantages that we consider based on the geometrics of the road, traffic levels and crash history."
For that reason, Edwards urged motorists to exercise extra caution. That includes ensuring tires and brakes are in good shape and there's ample gas in the tank — especially during the winter.
"And avoid being out on the roads (in bad weather) if you don't have to," Edwards added. "I'm an optimist, and I'd like to think that spring is around the corner. But I don't think winter is over yet."
This table shows the number of accidents reported by the Illinois Department of Transportation between mile marker 180.5 in Champaign County and mile marker 220, at the Illinois-Indiana state line in Vermilion County.
Source: Illinois Department of Transportation