A new study by University of Kansas engineering faculty and students documents how little crosswind is necessary to force a tractor-trailer into a rollover crash.
“We have found that a 15 to 20 mile-an-hour crosswind will blow over an empty truck,” said Tom Mulinazzi, professor of civil, environmental and architectural engineering.
A semi-truck hauling a full load can withstand much stronger crosswinds, up to 60 miles an hour, before being blown off the road.
Working with the Kansas Department of Transportation, the KU research group is formulating a number of strategies to warn motorists of the presence of strong crosswinds, Mulinazzi said.
The study, funded through the Mid-America Transportation Center, involved reviewing truck crash records from KDOT for 2005, 2006 and 2007 and tying that information to wind speed data collected at the time of the crash from weather stations near the accident sites. Kansas, which experiences strong north-south winds, averaged more than 1,000 wind-related crashes for each of the three years.
KU engineering graduate students Kelly Hovey, Romika Jasrotia and Yue Li and undergraduate student Jacob Pohlman found site and day specific data through Weather Underground, a commercial entity that collects and publishes weather information from more than 230 stations in Kansas. The KU team, working with associate professor Steven Schrock, chose to focus its research on days when more than 15 wind-related crashes occurred, as well as on crashes on the Interstate 70 corridor.
The crosswind danger affects truckers, operators of other high-profile vehicles, such as RVs and full-size vans, and motorists in the immediate vicinity of these vehicles. The risk exists in all seasons.
“We thought that a lot of it would be in the spring time, in May when we have a lot of strong winds,” Mulinazzi said. “We found that a lot of accidents occurred in November, December, January.”
Other weather conditions — such as snow, ice, rain or thunderstorms — often accompanied the high winds and lowered the wind speed necessary to blow over a high-profile vehicle.
To decrease the accident risk, the KU research team is formulating several recommendations for KDOT to consider. One option is to tie real-time wind condition data from nearby weather stations to the use of dynamic message signs already in use at several points along I-70. The signs currently alert motorists of road closures during hazardous winter conditions.
“We are concerned about the number of accidents related to strong, gusty winds and in particular to the number and severity of truck blow-over crashes attributable to wind,” said Leslie Spencer-Fowler, program manager of KDOT’s Intelligent Transportation Systems Unit. “The KU study gives us important information, and we are exploring ways in which we can utilize our existing electronic message signs as one way to alert motorists to the potential for a wind-related accident.”
Now the research team is looking for just the right message to communicate the potential crosswind danger to Kansas motorists. Another idea being proposed is the use of windsocks at roadway cutaways, bridges and overpasses, which would demonstrate immediate risk to motorists, as well as wind direction.
“Whatever we do, it has to be low cost,” Mulinazzi said.