Research

Penn State friction research aligns global safety efforts

Friction measurement devices are used to test roadway and airport tarmac surface friction characteristics under a range of dry and wet conditions. Researchers at Penn State’s Thomas D. Larson Pennsylvania Transportation Institute are working to help develop international standards for manufacturers of this key safety equipment. Credit: Penn StateCreative Commons

UNIVERSITY PARK, Pa. — If you're someone who drives or flies to get places, you probably know that friction is vital to ensure safe travel surfaces for cars and airplanes.

When researchers and manufacturers from nine companies representing five countries met up at Penn State this past summer, they helped move safety forward for roadways and airport runways worldwide.

Researchers at Penn State’s Thomas D. Larson Pennsylvania Transportation Institute hosted a comprehensive friction measurement workshop at the institute’s test track facility and at the University Park Airport.

The effort to unify approaches and upgrade technologies for measuring pavement friction is not new. The need was recognized decades earlier, and the Federal Aviation Administration has spearheaded the effort. Annual workshops have been held since the 1990s. However, led by Penn State researchers in coordination with the FAA and the Federal Highway Administration, the work accomplished over the past several years is beginning to bear fruit.

This year’s workshop, the sixth held at Penn State, is bringing the world’s friction experts closer than ever to realizing the goal of synchronized systems. The goal is to develop technologies, processes and standards that reach across multiple device types to establish a common basis for quality assurance to validate and harmonize the different sources of friction measuring equipment.

“We are entering an exciting stage in regard to implementation that will lead to new standards, which will be followed by agencies and manufacturers worldwide,” said Zoltan Rado, director of the workshop and senior research faculty at the Larson Institute.

The workshop utilized several calibration stations to analyze each subsystem of each friction measurement device, said Rado. Static evaluation of each subsystem and dynamic evaluation of each device makes it possible to account for differences in principles and testing of international systems. Technical aspects evaluated included force, water film distribution, speed, and for some devices whose measurement wheel doesn’t lock, the slip ratio of the test tire.

“This is my sixth time here,” said Frank Holt, of Dynatest Consulting, in Alpharetta, Georgia. “Penn State does an impressive job with this event.”

Holt said the workshop’s calibration process covers all known friction measuring devices currently in use.

“The calibration platform (in the United States) is about 50 years old,” said Holt, but was never applied to all devices. The testing and analysis conducted at this workshop is generating data that will help standardize the equipment and universalize friction quality for roadways and runways worldwide. 

“Manufacturers, like me, benefit greatly,” said Holt. “This puts all of us on an equal footing.”

The public benefit also is clear. “Standardizing friction equipment can give the public more faith in the producers and in our overall transportation system," Holt said. "This will enable the FAA to strengthen regulations and lead to new certifications for devices.”

Raymond Zee, a civil engineer and airport airspace specialist representing the FAA at the workshop, acknowledged important progress is underway.

“I’m very pleased," he said. "We are moving in a good direction.”

The International Friction Workshop is hosted by the Vehicle Systems & Safety program of the Larson Institute at Penn State. For more information about the workshop or the Vehicle Systems & Safety program, contact Zoltan Rado at zxr100@psu.edu.

Last Updated December 18, 2015