Nav: Home

Variable speed limits could reduce crashes, ease congestion in highway work zones

June 06, 2017

COLUMBIA, Mo. - As the summer months approach, most people turn to thoughts of sunshine, outdoor barbecues and destination trips. Yet travelers often are greeted by detours, lane closures and delays for road repairs that generally are reserved for warmer weather. Researchers at the University of Missouri have studied systems to alleviate inevitable backups and delays. Researchers found that using variable speed limits in construction zones may ease congestion, reduce crashes and make work zones safer for both workers and travelers nationally.

With assistance from the Missouri Department of Transportation, Praveen Edara, associate professor of civil and environmental engineering in the MU College of Engineering, tested the use of variable advisory speed limit (VASL) systems and the effect they may have on lessening congestion and reducing rear-end and lane-changing accidents on a fairly dangerous stretch of I-270, a major four-lane highway in St. Louis.

"The idea was to see if warning drivers of slower speeds ahead helped reduce crashes," Edara said. "Where there is queueing, if drivers are not aware of the queue downstream, they don't have enough time to hit the brakes to slow down or stop, thus, increasing the likelihood of a crash. Instead of posting a message asking them to slow down, the VASL system posts an advisory speed limit based on the actual downstream traffic speed, so drivers would know that if they're driving 50 mph, they should slow to 30 mph downstream."

Edara's data collection and simulation analysis uncovered a few key pieces of data. First, the use of VASL systems is effective in gradually slowing drivers as they enter work zones. VASL use resulted in a 39 to 53 percent decrease in average queue length, and just a 4 to 8 percent increase in travel time.

Additionally, using VASL meant that maximum speed differences also decreased by as much as 10 mph, and the chance of rear-end collisions dropped by 30 percent. Researchers also noted a 20 percent decrease in lane changing conflicts. Essentially, travel time was slightly longer, but lines were shorter and collisions were less frequent.

"You can get both safety benefits and mobility benefits by deploying variable advisory speed limit systems in work zones," Edara said.

"Evaluation of variable advisory speed limits in congested work zones" recently was published in the Journal of Transportation Safety and Security. Carlos Sun, an MU professor of civil and environmental engineering, and Yi Hou a doctoral student at Mizzou, co-authored the study.
-end-


University of Missouri-Columbia

Related Engineering Articles:

Engineering a new cancer detection tool
E. coli may have potentially harmful effects but scientists in Australia have discovered this bacterium produces a toxin which binds to an unusual sugar that is part of carbohydrate structures present on cells not usually produced by healthy cells.
Engineering heart valves for the many
The Wyss Institute for Biologically Inspired Engineering and the University of Zurich announced today a cross-institutional team effort to generate a functional heart valve replacement with the capacity for repair, regeneration, and growth.
Geosciences-inspired engineering
The Mackenzie Dike Swarm and the roughly 120 other known giant dike swarms located across the planet may also provide useful information about efficient extraction of oil and natural gas in today's modern world.
Engineering success
Academically strong, low-income would-be engineers get the boost they need to complete their undergraduate degrees.
HKU Engineering Professor Ron Hui named a Fellow by the UK Royal Academy of Engineering
Professor Ron Hui, Chair Professor of Power Electronics and Philip Wong Wilson Wong Professor of Electrical Engineering at the University of Hong Kong, has been named a Fellow by the Royal Academy of Engineering, UK, one of the most prestigious national academies.
Engineering a better biofuel
The often-maligned E. coli bacteria has powerhouse potential: in the lab, it has the ability to crank out fuels, pharmaceuticals and other useful products at a rapid rate.
Pascali honored for contributions to engineering education
Raresh Pascali, instructional associate professor in the Mechanical Engineering Technology Program at the University of Houston, has been named the 2016 recipient of the Ross Kastor Educator Award.
Scaling up tissue engineering
A team at the Wyss Institute for Biologically Inspired Engineering at Harvard University and the Harvard John A.
Engineering material magic
University of Utah engineers have discovered a new kind of 2-D semiconducting material for electronics that opens the door for much speedier computers and smartphones that also consume a lot less power.
Engineering academic elected a Fellow of the IEEE
A University of Bristol academic has been elected a Fellow of the world's largest and most prestigious professional association for the advancement of technology.

Related Engineering Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...