Study: Widening Two-Lane Roads, Shoulders Could Add To Crash Risk

By Stephanie Reitz

Associated Press

STORRS — Widening the travel lanes and shoulders on two-lane roads can give drivers a false sense of security, leading to higher speeds and the potential for more severe head-on crashes, according to a new study.

The University of Connecticut study, released March 23, said head-on crashes on two-lane roads are most likely to occur on stretches with frequent curves, sharp turns, hills and several retail and commercial driveways.

John Ivan, an associate professor of civil and environmental engineering at UConn and author of the study, said the extra-wide shoulders added to some of those roads seem to send an inadvertent signal to drivers that faster speeds are safe.

They restrict their speeds more often when they feel hemmed in on narrow, potentially hazardous stretches, he said. But wider lanes and shoulders lend the feel of more room for correction than actually exists.

“Drivers are largely having trouble determining what is a safe speed,” Ivan said. “When you’ve got these wide roads, the things you might hit are farther away from you, so you’re more confident going faster.’’

Expanding shoulders to six feet does, however, add to a two-lane road’s safety, he said. But widening shoulders beyond that or making lanes unnecessarily wide seems to be adding only extra pavement, not extra safety, he said.

About two of every five crashes nationwide occur on two-lane roads, but they tend to be more serious than those on highways, according to federal transportation statistics.

In fact, 75 percent of the nation’s fatal crashes each year occur on two-lane roads, usually either when a driver veers off the road and strikes an object or heads into incoming traffic.

Older, narrow two-lane roads are common in Connecticut and other Northeast states, which grew long before the spread of city planning, traffic design standards, and other measures intended to make roads safer.

Sprawl adds to the problem, increasing the number of cars and trucks on two-lane roads that inadvertently become the main artery to many growing suburban towns, the study says.

Ivan’s study examined crashes on 720 two-lane rural segments in Connecticut of one kilometer each. They varied in their topography, width, traffic volume, and other factors.

He said he does not want his report interpreted to blame the state Department of Transportation, since it is understandable that state agencies use nationally accepted traffic planning standards —which include wider shoulders — to protect themselves from liability.

However, he said, some of the problems on Connecticut’s two-lane roads might be eased by creative solutions.

The Transportation Department in 1999 added a rumble strip on the center line of two-lane Route 6 in Bolton, following the lead of other several other states that cited sharp decreases in head-on crashes using the same method.

Neighbors and business owners along that stretch of road complained about the noise generated by the rumble strip, however, and transportation officials eventually paved it over.

Ivan said transportation planners should try those kinds of creative solutions more often.

“I think there’s a lot of well-meaning designs,’’ he said, “but I really do think they can be more innovative and thoughtful.’’

He also cited the “two plus one” design used in some other states, in which a passing lane is added at some spots on two-lane roads so drivers can overtake slower cars without pulling into oncoming traffic.