'Super circles' to lessen rush-hour headaches

Mar 13, 2014

While Mother Nature continues to challenge drivers across the country, a team of traffic engineers is working hard on a new way to make rush-hour commutes safer and faster in any weather.

"We can't do much about snow falling, but we can do something about road capacity and congestion," said Joseph Hummer, engineering expert and Wayne State University College of Engineering chair of civil and .

Hummer and a team of traffic engineers at the Regional Transportation Alliance and North Carolina State University believe metered roundabouts, or "super circles," could help safety and ease across the United States. According to the team's research, explained in a paper titled "The Potential for Metering to Help Roundabouts Manage Peak Period Demands in the U.S.," super circles are common in Australia and England, but have yet to be researched or implemented in the U.S. The research team built and tested a mathematical model of traffic flow through super circles.

Roundabouts have been implemented in the United States for some time. Hummer says when built correctly they are 30 to 40 percent safer than traditional signalized intersections and offer a 60 percent injury savings.

"The one classic dilemma with roundabouts, though, is that some have capacity issues during peak hours. Once they break down, they get ugly and lock up. Our research was trying to find a way to get the safety benefits of a traditional roundabout while creating a capacity treatment for the peak hours of the day," he says.

A "super circle" involves adding a stop light to one approach of a roundabout to control the number of vehicles entering during rush hours. "The meter would only operate during peak hours and would free up space in the circle for the busiest traffic streams to enter," he says. The rest of the day, with the meter turned off, the roundabout would do its job saving collisions.

Here in Michigan, Hummer can envision utilizing super circles in a number of places.

"Michigan is really well suited to metered . I could find hundreds of places of these in Metro Detroit alone at the junctions of the mile roads," says Hummer. "They aren't suitable for the huge arterials like Woodward, Gratiot or 8 Mile, but would work almost anywhere you have two, two-lane roads meet at a traffic signal."

According to Hummer, a modern roundabout costs, on average, $250,000 while the cost to society for a fatal collision or injury collision averages around $4 million and $100,000, respectively.

"The super circles wouldn't have to be out there too long to justify costs, at least on a societal basis. But the biggest benefit from all would be the lives and injuries saved," he says.

Hummer and the team members, who now aim for field studies and a more microscopic analysis, presented their research at the Transportation Research Board (TRB) Annual Meeting, held Jan. 12 to 16 in Washington, D.C. The team's paper has been accepted for publication in Transportation Research Record.

Explore further: Researchers design a new system to make overtaking safer on highways

Related Stories

9 million bicycles, but what about the cars in Beijing?

Mar 27, 2012

Forget the fact of there being "9 million bicycles in Beijing, that's not a fact. Indeed, motor vehicle traffic is fast becoming a big problem that has led to unsustainable pollution and draconian rules in some parts of the ...

Brighten up! Paint study could save states millions

Mar 10, 2009

A new study from North Carolina State University shows that painted road markings, such as the lines separating traffic lanes, are significantly better at reflecting headlights in the direction that the paint was applied. ...

New study examines traffic congestion on a university campus

Mar 25, 2008

Some researchers believe that the United States is in a “congestion crisis”. Indeed, national transportation statistics indicate that 42 percent more vehicles used each urban lane mile in 2000 than in 1980, tripling the ...

Recommended for you

Drone postal deliveries begin in Switzerland

6 hours ago

Wondering where your package is? Look up! Switzerland's postal service said Tuesday it had begun testing parcel deliveries by unmanned drones, although widespread use of the flying postmen is not likely to kick in for another ...

Omnidirectional free space wireless charging developed

6 hours ago

Mobile devices, such as smartphones and laptops, have become indispensable portable items in modern life, but one big challenge remains to fully enjoying these devices: keeping their batteries charged.

Europe's deepest glider to be developed

Jul 06, 2015

19 partners from across Europe have come together to develop Europe's first ultra-deep-sea robot glider. This glider will be capable of sampling the ocean autonomously at depths of 5000m, and maybe more in ...

Researchers help reconstructing the Michelangelo bronzes

Jul 06, 2015

Engineers and imagers from the University of Warwick's Warwick Manufacturing Group (WMG) and anatomists from Warwick Medical School at the University of Warwick are helping Art historians from the University ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Nik_2213
not rated yet Mar 13, 2014
My UK route meets several and, surprisingly, they help more than you'd expect. Knowing the 'part-time' lights will soon change and let you through removes a lot of 'aggro'. Also, a driver baulked at the entrance to a 'standard' roundabout may be stuck half-way out, both slowing flow on the roundabout and needing a bigger gap to go. That's solved, too...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.