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.
Jeff Sossamon | EurekAlert!
New players, standardization and digitalization for more rail freight transport
16.07.2018 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)
A helping (Sens)Hand
11.04.2018 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO
Vaccinia viruses serve as a vaccine against human smallpox and as the basis of new cancer therapies. Two studies now provide fascinating insights into their unusual propagation strategy at the atomic level.
For viruses to multiply, they usually need the support of the cells they infect. In many cases, only in their host’s nucleus can they find the machines,...
More than one hundred and fifty years have passed since the publication of James Clerk Maxwell's "A Dynamical Theory of the Electromagnetic Field" (1865). What would our lives be without this publication?
It is difficult to imagine, as this treatise revolutionized our fundamental understanding of electric fields, magnetic fields, and light. The twenty original...
In a joint experimental and theoretical work performed at the Heidelberg Max Planck Institute for Nuclear Physics, an international team of physicists detected for the first time an orbital crossing in the highly charged ion Pr⁹⁺. Optical spectra were recorded employing an electron beam ion trap and analysed with the aid of atomic structure calculations. A proposed nHz-wide transition has been identified and its energy was determined with high precision. Theory predicts a very high sensitivity to new physics and extremely low susceptibility to external perturbations for this “clock line” making it a unique candidate for proposed precision studies.
Laser spectroscopy of neutral atoms and singly charged ions has reached astonishing precision by merit of a chain of technological advances during the past...
The ability to investigate the dynamics of single particle at the nano-scale and femtosecond level remained an unfathomed dream for years. It was not until the dawn of the 21st century that nanotechnology and femtoscience gradually merged together and the first ultrafast microscopy of individual quantum dots (QDs) and molecules was accomplished.
Ultrafast microscopy studies entirely rely on detecting nanoparticles or single molecules with luminescence techniques, which require efficient emitters to...
Graphene, a two-dimensional structure made of carbon, is a material with excellent mechanical, electronic and optical properties. However, it did not seem suitable for magnetic applications. Together with international partners, Empa researchers have now succeeded in synthesizing a unique nanographene predicted in the 1970s, which conclusively demonstrates that carbon in very specific forms has magnetic properties that could permit future spintronic applications. The results have just been published in the renowned journal Nature Nanotechnology.
Depending on the shape and orientation of their edges, graphene nanostructures (also known as nanographenes) can have very different properties – for example,...
03.12.2019 | Event News
15.11.2019 | Event News
15.11.2019 | Event News
13.12.2019 | Physics and Astronomy
13.12.2019 | Physics and Astronomy
13.12.2019 | Materials Sciences