The University of Massachusetts Amherst
University of Massachusetts Amherst

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Knodler Settles the Difference Between a Rotary and Roundabout in First Video of UMass Transportation Center Series

Stil image of an empty rotary

“Is there a difference between a rotary and a roundabout?” Boston Globe correspondent Morgan Hughes asked a very New-England-centric question in a recent edition of the Globe. “Transportation experts at the University of Massachusetts Amherst have the answer.” Yes, the UMass Transportation Center has launched a series of informational videos that explore a range of issues often questioned by the driving public. The series is made up of short, five- to 10-minute videos released monthly and hosted by staff from the center.

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See News Office release »

As Hughes concluded in the Globe piece,  “In the first video of the University of Massachusetts Transportation Center’s series, Transportation Take-Away,  center director Michael Knodler compares and contrasts the two circular traffic patterns. Roundabouts are the more modern version of a rotary, Knodler explained in the video. They’re smaller, slower, and safer, he said. Massachusetts has even been phasing out rotaries in favor of roundabouts, the Globe reported last year.

Knodler, a professor in the Civil and Environmental Engineering Department, hosts the first episode about the difference between a roundabout and a rotary. Knodler explains that there are key differences between the two types of familiar circular roadways. Rotaries are much larger and allow traffic to move at a higher rate of speed, while roundabouts are smaller in diameter with traffic moving much slower. He also talks about the safety implications of round roadways compared to intersections with traffic lights.

Other issues that will be looked at in the video series include: the relationship between marijuana use and safe driving; how drones are being used to improve roadway designs and transportation safety; how speed limits are set and the role state and local officials play in the process; and the relationship between marijuana use and safe driving. (November 2018)