Study: Signs may not make uncontrolled rural intersections safer

DES MOINES - Posting traffic signs at unmarked rural intersections would not necessarily prevent crashes such as the three that occurred over the past two weeks and claimed the lives of five Iowans, a 2005 Iowa study said.

Stop or yield signs appear to have little effect on the safety of low-traffic, rural intersections, the study said.

The study was conducted by Iowa State University's Center for Transportation Research and Education and was sponsored by the Iowa Department of Transportation and the Iowa Highway Research Board.

'For ultra-low-volume rural unpaved intersections, type of control has negligible effect on safety performance,” the 2005 report said.

On Aug. 6, three brothers aged 10 to 16 were killed when their car collided with a truck near New Sharon at an uncontrolled intersection, one without stop or yield signs.

On Tuesday, a Sumner woman died after her car collided with a truck at an uncontrolled intersection in rural Bremer County.

The fatal crashes have drawn attention to Iowa's uncontrolled intersections - there are nearly 22,000, according to Iowa Department of Transportation data - as people wonder whether a stop sign would have saved lives in either crash.

In Mahaska County, where the three brothers died, the county is considering placing a stop sign at the intersection where the crash occurred.

'We may never know all that happened out there at that accident, but we can offer support for the family and do the best we can and look at all the stuff so we can avoid these in the future, if there is such a way of doing that,” Mahaska County engineer David Shanahan told WHO-TV in Des Moines last week.

But the 2005 study said the data shows low-traffic, rural intersections are no safer with stop or yield signs than they are without.

'It really isn't as simple as what we thought of when we first heard the situation (of the crashes) - ‘Hey, put up a stop sign out there,'” said Steve Gent, director of traffic and safety for the Iowa DOT.

Gent said crashes at uncontrolled rural intersections are rare, although he said the DOT does not have good data that measures such incidents. He said traffic on those roads is extremely light, and the vast majority of traffic consists of local residents who know the roads and the area.

Gent said it's 'extremely rare” to have two vehicles even meet at those intersections.

'And both (drivers), likely, are local, so both know it's really a yield,” Gent said. 'Nobody has the right of way, so they know everybody has the responsibility to watch for (other vehicles).”

Gent said it's mostly a seasonal issue because crashes such as the ones in Mahaska and Bremer counties typically happen when corn crops are tall, causing decreased visibility at the intersections.

For most of the year, drivers approaching those uncontrolled intersections clearly can see other vehicles approaching.

But particularly when corn is high in the late summer, it can be difficult for drivers to see other vehicles coming from a long distance.

Gent, who said he has served in traffic safety jobs for 25 years, said uncontrolled intersections have a regional flavor nationally. He said there are very few in the Eastern states, and many in the Western states.

He said Iowa and the Midwest fall somewhere in the middle.

The 2005 Iowa State study examined 6,846 unpaved rural intersections, more than half of which were uncontrolled. The study found that 92 percent of the intersections had no crashes in 10 years and that the few crashes occurred at similar rates at controlled and uncontrolled intersections.

'Those types of crashes take so little to avoid them,” Gent said. 'If somebody hits their breaks 100 feet quicker it doesn't happen. It's really those kind of rare situations.

'It's really a tough thing.”