Intersections with flashing lights riskier than those with stop signs (from The Republic, Columbus Ohio – AP story)

By clair  |  Highways

(image from

Intersections with flashing lights have three times more accidents than those with only stop signs and intersections with highway frontage roads are high risk, a University of Texas study released Monday said. The study, led by Cockrell School of Engineering Professor Chandra Bhat and his graduate students, Marisol Castro and Rajesh Paleti, examines which types of intersections are most dangerous for drivers, and its findings could lead to improved guidelines on how to design and construct safer intersections.

One fatality occurs on U.S. roadways every 16 minutes, and the frequency of crashes typically increases over the holiday season. December and January are the months with the highest rates (per vehicle mile traveled) of traffic crashes, Bhat said. His study could not determine if flashing lights at intersections confused drivers or if traffic engineers have placed flashing lights at the most dangerous intersections.

(Dr. Chandra Bhat, UT Austin)

“Intersection and intersection-related crashes account for roughly 40 percent of all crashes,” said Bhat, a leading authority on transportation engineering and a professor in the school’s Department of Civil, Architectural and Environmental Engineering. “Understanding their causes should be a priority for transportation and safety professionals, so that we can develop countermeasures to reduce the high incidence of crashes and resulting deaths and injuries at intersections.” Bhat used data collected by the Texas Dept. of Transportation.

Drivers exiting highways are also more likely to crash, either because they are going too fast or switching lanes in a dangerous manner.

A key finding of the study is that intersection accidents are affected by the larger traffic network around them, and that fixing a dangerous intersection will reduce accidents on neighboring streets.

“If you don’t account for this dependence, which is what almost all earlier studies have done, you underestimate the value of roadway and traffic control improvements,” Bhat said.

Intersections with traffic lights are the safest, the study found. But once an accident begins to develop, it is harder to stop. The study introduces a unique way to capture the effect of the traffic volume splits on major and minor roadways at intersections. When the amount of traffic on a minor roadway is close to the amount of traffic on an intersecting major roadway, the chances of a crash are significantly increased. If the traffic volume is disproportionate, however, (with the smaller roadway having far less traffic than a heavily traveled, major road) crash risks are reduced.

Researchers will present the findings at the National Transportation Research Board Meeting in Washington next month.

Watch video and read the news story on KVUE.
December 21, 2011, Evening News

December 21, 2011, Evening News

FOX 7 Austin
December 26, 2011, 9PM News

December 19, 2011

Original sources:

The Republic:–Traffic-Accident-Study/

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