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News Release

October 29, 2003

New Traffic System May Improve Driver Behavior in Merge Situations


ST. PAUL, Minn. Fifteen percent of drivers admitted to straddling lanes in order to block late merges in construction zones, according to a recent study conducted by the Minnesota Department of Transportation.

To address the more than 2,700 crashes and 18 fatalities occurring in highway construction zones last year, Mn/DOT commissioned a study to better understand the behaviors and attitudes that trigger driving decisions in merging situations as drivers enter a work zone.

"Our goal is to increase safety in work zones by reducing the confusion and frustration drivers often experience when merging," said William Servatius, Mn/DOT's Office of Construction. "Many times crashes occur due to aggressive driving, abrupt lane changes or sudden stops, so we want to help drivers make good choices while traveling through our work zones."

In an attempt to minimize the problems discovered in the research, Mn/DOT also conducted a month-long field study on Highway 10 in Anoka to assess a new Dynamic Late Merge System, a traffic control strategy to improve merging at lane closures.

"The fully automated system using remote traffic microwave sensors and a Doppler radar provides instructions to drivers via changeable message signs on when to merge and how to merge according to the current state of traffic," said Craig Mittelstadt, Mn/DOT's workzone safety specialist. "For example, if traffic is heavy, the system will instruct motorists to use both lanes and take turns once they've reached the defined merge point just before the lane closure."

This strategy often referred to as the "zipper" improves traffic flow, reduces conflicts and hopefully will decrease the number of crashes when traffic demand exceeds the capacity of a single lane closure.

"Basically, we want drivers to know that under normal traffic speeds, they should try to merge early to avoid unsafe merging maneuvers; however, when traffic is congested, drivers should use both lanes all the way to the definite merge point," said Servatius.

"We can't completely rid the roads from congestion in a workzone, but data from the study revealed this method shortened queue lengths by 35 percent and reduced lane changing conflicts," said Mittelstadt. "We also hope for a decline in crashes and aggressive driving behavior."

Minnesota is one of the first states to use the Dynamic Late Merge System and plans are to continue this research in the upcoming construction season.

"People have been trying for years to research the proper way to merge, but there are so many factors to consider," said Servatius. "It's difficult to say what's the 'right' way - instead we're looking for the best way."

Traveler information, including incident reports, is available by calling 511 or logging on to Know the Road. Dial up or log on.




Daneeka Marshall-Oquendo 651/296-8609
Cell: 651/270-2667

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