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Transportation Safety Issues and Priorities in Minnesota

Brad Estochen, Assistant State Traffic Engineer, Minnesota Department of Transportation

December 1, 2011

Brad Estochen

When a fatal crash occurs, traffic safety professionals often face a troubling question: “How many people have to die before something is done?” But a new Minnesota Department of Transportation (MnDOT) traffic safety strategy is aiming to eliminate that question entirely.

Speaking at the December 1  Advanced Transportation Technologies Seminar, MnDOT State Traffic Safety Engineer Brad Estochen said that defining traffic safety often depends on whom you ask. “Everyone defines it differently depending on their point of view, but in the end it’s all about crashes,” he said. “The number of crashes is how we assess our progress.” And progress in Minnesota has been significant; since MnDOT shifted its focus from preventing total crashes to preventing fatal and serious injury crashes in 2003, the number of people severely injured and killed on state roadways has dropped dramatically. However, with more than 400 people killed a year, Minnesota still has a ways to go before achieving its ambitious target of zero traffic fatalities.

Minnesota is working toward achieving zero deaths using a data-driven framework focused on both reduction and prevention. Crash reduction is being accomplished with two primary tools. The first, the Crash Data Tool Kit, ranks the relative “danger” of intersections and road segments by applying a value to various crash severity levels. Although its ability to compare locations is useful for screening, the tool kit can also be rigid and doesn’t allow for dynamic analysis.

The second crash reduction tool is the Road S.M.A.R.T. application, which helps identify 75 predefined crash trends such as impaired driving, run-off-the-road crashes, pedestrian crashes, and more. “This tool is not constrained by predetermined segment lengths, so it permits apples-to-apples comparisons on a mile-by-mile basis with a lot more flexibility,” says Estochen.

In addition to crash-reduction measures at high-risk locations and corridors identified by the Crash Data Tool Kit and Road S.M.A.R.T., Minnesota is earning national recognition for its innovative approach to crash prevention. “Severe crashes are random and rare; we don’t have a dead man’s curve or a killer corner,” said Estochen. “Our current tools fall short in predicting where these crashes will occur because with 400 fatal crashes a year, we don’t have a vast data set to draw from.”

To prevent fatal and serious injury crashes in the future, the MnDOT approach takes the traditional model and turns it on its head. “Instead of looking at individual locations and then looking at the crash types, we’re looking at crash types and then investigating the characteristics of the locations,” Estochen said.

Using this approach, Estochen’s team has made some remarkable discoveries. For example, when studying rural crashes, they found that while less than 15 percent of the road network is curved, more than 50 percent of fatal and serious injury crashes occur on curves. They then examined the characteristics of curves—such as volume, crash history, intersections, and radius—to determine what makes them most dangerous. “What we learned is that it’s not the really sharp or really subtle curves that are the most dangerous, it’s the ones in between, where you don’t realize you need to slow down until it’s too late,” he said.

Safety insights like these are now being used in Minnesota to make safety improvements on a system-wide basis. According to Estochen, prevention strategies such as these are what is needed to drive safety progress as Minnesota’s fatality and serious injury numbers continue to drop.