Steel safety cables that state officials have been working to install in many highway medians could have saved the four young women killed Monday in a crash on a rural stretch of Interstate 94 near Alexandria, traffic experts say.

But placement of barriers, which cost up to $150,000 per mile to install, is based on traffic volume, the number of crashes and average speeds, said Bernie Arseneau, deputy commissioner and chief engineer for the Minnesota Department of Transportation (MnDOT).

"This is a very low-volume section of 94," Arseneau said. "This wouldn't be one of those areas where it would stand out" to have the cables, those taut bands of steel strung in lines of three or four that increasingly line miles of highways.

Since the barriers were first installed in 2004 on Interstate 94 in the northwest metro, more of the steel cables have been added every year to divided highways all around Minnesota, primarily in the heavily traveled Twin Cities area.

According to the latest MnDOT data, there are 260 or so miles of highway with the cable barriers, and another 79 miles are on the drawing board this year. Still, Arseneau said, "there's much more four-lane that doesn't have cable than does.

"Ideally we would have cable barriers all along I-94, and we are moving to that end," he said. "It's ultimately an ending pot of money. We have to be smart about how we go ahead."

From 13 deaths to 0

When Lauren Peterson's Chevy Malibu slid off I-94 west of Alexandria with three fellow North Dakota State University students with her, the vehicle continued unimpeded into eastbound traffic and collided with a much larger Chevy Suburban.

Such head-on collisions are exactly the type of crash the barriers are designed to prevent.

A state study released last year found a stark difference between having cables and not having them.

In the first four years that the cables were installed, covering about 75 miles almost exclusively in the Twin Cities area, there were no fatalities in that area in crashes involving running off the road, colliding head-on or sideswiping a vehicle heading the other way. For the three years previous along those same miles, there were 13 deaths in those types of crashes.

The study found all types of injury crashes -- from incapacitating to minor -- were reduced. But the number of property damage crashes rose starkly -- from 162 to 632 -- because vehicles are hitting the cables and not merely rolling to a stop in the median.

"It's not like just spinning out," State Patrol Lt. Eric Roeske said. However, he added, "they are designed to prevent those types of crashes," those like the crash Monday.

"It's a tradeoff," Roeske said. "No trooper is going to say I'd rather write a quadruple fatal [report] than a property crash."

Lee Munnich, a rural highway safety expert at the University of Minnesota, says that the location of Monday's crash "seems like an appropriate place for a barrier like that. The cables are the only thing I think could've have stopped" the women's car.

"There probably still would have been a crash," Munnich added, "but they all had their seat belts on. Even if they would've been in a crash on the same side of the road or flipped, [had the cables been there], they probably would've been protected."

Arseneau sympathizes with public sentiment in the wake of the crash for somebody to "do something" and make highways safer.

"This was absolutely tragic," he said, noting that he lives in Rogers, where two of the victims graduated from high school last year. "I'm getting a whole bunch of questions from my neighbors."

Arseneau said that improved highway engineering is just one area of emphasis as Minnesota pushes ahead with its nationally mimicked Toward Zero Deaths traffic safety campaign. Driver behavior, education and enforcement are also important factors that he says have pushed down the traffic fatality rate in the state to historically low levels.

Tragedy prevented in '08

One of the most dramatic moments for the cables came south of St. Cloud in March 2008, when a semitrailer truck was kept on the eastbound side of I-94 for more than a quarter-mile by the barrier during the afternoon rush hour. The truck hit only the cables, and the driver came away with minor injuries.

The truck, weighing 40 tons, including its contents, "rode the barrier for 500 yards," the patrol said in its report, and "stopped the semi from crossing into westbound traffic."

University of Minnesota, Morris senior Kelli Hamilton drove west on I-94 a few hours after Monday's crash, protected virtually the whole way by barriers until she exited at Sauk Centre.

Hamilton said she never noticed the median cables during those many trips between her family's home in Delano and school. Then her father called her the morning after the crash, and they talked about the absence of cables at that spot.

"It's dumb that they don't have barriers all along the highway," she said. "If you're going to do something, do it right."

She said her family has had a heightened awareness about traffic safety since her grandmother died in a car crash years ago.

"We get the lecture," she said. "Seat belts on, phones off. Pay attention."

Paul Walsh • 612-673-4482