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STORRS, Conn.— Head-on collisions on American roads accounted for only three percent of traffic accidents in 2003, but 10 percent of traffic deaths that year, making them among the most serious accidents drivers can have.
In a recent study, transportation researchers at the University of Connecticut looked at road conditions related to the occurrence of these accidents, their severity and what Connecticut can do to help prevent them. The study was funded by the New England University Transportation Center, a program sponsored by the U.S. Department of Transportation.
The researchers, led by John Ivan, an associate professor of civil and environmental engineering studied 720 different 1 km segments of two-lane highways in Connecticut and the head-on collisions that occurred on them over a five year period. Ivan worked with Professor Per Garder with the University of Maine and the study examined roadways there as well. Nationwide, 75 percent of traffic fatalities occur on two-lane roads.
"With the population here in New England continuing to spread outside of urban areas, traffic volumes are increasing on two-lane rural roads and we can expect the frequency of head-on crashes to increase," said Ivan.
Nationally, 83 percent of two-lane undivided road crashes occur on rural roads and the possibility of a fatality occurring during a head-on crash is three times higher in rural areas.
Ivan and his team first looked at what road design conditions were correlated with head-on collisions. Not surprisingly, areas where head-on collisions are most likely to occur are:
- Roads with frequent curves that require more steering to navigate
- Roads with sharp turns
- Roads that rise and fall, temporarily blocking a driver's view of oncoming traffic
The study showed that the severity of head-on collisions increases when:
- The road surface is wet
- The paved surface is narrow (less than 30 feet)
- There are a lot of business and retail driveways along the road
- One is driving between the hours of 10:00pm and 6:00am
The study notes that the density of access points on the road - driveways for businesses or retail areas - and where they are located are related to the outcomes of head-on crashes. For example, in areas with a lot of access points, fatal head-on crashes are more likely to occur. Specifically, a large number of office driveways are correlated with less severe crashes, while a large number of retail-use driveways is associated with more severe crashes. Ivan noted that this suggested that people may drive at higher speeds in retail areas, or because the traffic volumes in their vicinity are higher at night when the most severe crashes occur. Ivan outlined what Connecticut and other states, particularly in New England, do to improve the safety of these roads.
"Obviously head-on collisions occur when drivers cross the center line and many of these accidents happen because it is late at night and they are drowsy and accidentally cross the line or because they lost control of the car," said Ivan.
"So more signs and pavement markings are not going to address the problem, what will help reduce these kinds of crashes is keeping drivers alert or preventing such crossings of the center line. This can be done by installing rumble strips in the center of the road and creating a raised median at the center on curves.
The state department of transportation has tried this on Route 6 in Bolton, but residents complained about the noise caused by vehicles driving over the rumble strips, so they were paved over. Since retail areas appear to experience more severe crashes, and perhaps have fewer
residents to complain, it might be most beneficial to install these treatments in those areas.
Ivan stated that some of the report can also be used when looking at roads with more lanes than two.
"While Route 44 on Avon Mountain is a multi-lane rather than a two-lane road, some of these lessons can be applied there as well," said Ivan. "The proportion of head-on crashes there is similar to that on two-lane roads, and remedies that would prevent such crashes on two lane roads would work on a multi-lane road as well. Certainly widening the pavement beyond a total
of 50 feet will only encourage drivers to go faster than the limit for negotiating some of the sharper curves."
Two of the road segments examined were on Route 44 in Coventry.
"While the best way to address the problem is to reduce or straighten the number of moderate to sharp curves on roadways, trying to design straight, flat rural roads in a place like New England would be prohibitively expensive," Ivan said.
"Adding a six foot shoulder on the side of the road can reduce the severity of these crashes because it would give drivers additional space to maneuver.
"However, too often when roads are widened, we will see 8 to 10 foot shoulders.
This study indicates that anything greater than six feet carries no additional safety benefits and in fact, roads that are too wide encourage greater speed by drivers, making them less safe. This is in addition to the great cost of making roads too wide, which can also create neighborhood opposition by eating up more land. Four to eight feet can sometimes mean the difference between taking a house and not taking it. In the end, this study shows that it is likely unnecessary."
For a full copy of the study, contact Professor John Ivan at 860-486-0352 or john.ivan@uconn.edu or Michael Kirk in UConn Media Relations at 860-486-0715 or michael.kirk@uconn.edu
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