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Federal Highway Administration > Publications > Public Roads > Vol. 62· No. 4 > "Sticking" with ROSAN

Jan/Feb 1998
Vol. 62· No. 4

"Sticking" with ROSAN

by Maria Koklanaris

High-speed race car drivers call it "stick."

When they're rounding a high-banked turn at 260 kilometers per hour, that's what they want the wheels of the car to do to the asphalt underneath. But since most NASCAR tracks are repaved only about once every five years, chances are the driver is making the turn on asphalt that has become much too smooth for his taste.

It may even be too smooth for his safety. There's not enough stick.

What can the race track manager do to avoid this problem? Call in ROSAN.

ROSAN van
ROSANvm on the bar mounted to the van is measuring the track surface Charlotte (N.C.) Motor Speedway.

ROSAN, the short name for the Road Surface Analyzer, will soon be available for market through an agreement between the Federal Highway Administration (FHWA) and a private company in South Carolina. The company, Surfan Engineering and Software Inc., has teamed with FHWA in a cooperative research and development agreement (CRADA).

Such CRADAs are the vehicle to get products developed at FHWA's Turner-Fairbank Highway Research Center (TFHRC) out of the lab and into the hands of state agencies and private industry. ROSAN might not have been available to play its part if not for FHWA's partnership, or CRADA, with Surfan Engineering and Software.

"If we don't have a private partner, then we can't advance the technology. We don't manufacture and sell materials," said Bob Betsold, FHWA's associate administrator for research and development. "It's very important that we line up our partners as the technology advances. Then we have to nurture that partnership."

In the case of ROSAN, which should be ready for market by March 1998, the highway industry will get a product that completely changes the way engineers and technicians characterize pavement. They can use the information either for new construction quality assurance control or for pavement monitoring programs. It can also be used to measure road roughness (profiling) longitudinally and transversely to the direction of travel.

ROSAN laser and van
A close-up look at the ROSANvm, a laser sensor that is moved along the bar by a computer controlled motorized trolley.

In just one testing session, the automated and computerized device, which is mounted on a vehicle and does its testing while the vehicle is moving at normal traffic speeds, can gather data on 160 kilometers of pavement. ROSAN specializes in measuring macrotexture, any change in the pavement surface that is greater than 0.5 millimeters and less than 5 millimeters. That data can be used to forecast the life of the pavement.

For that race car driver, it means the manager would know when to repave the track before it loses its stick.

"What we can provide those people is a way to measure when they need to repave," said Scott Clements, president of Surfan Engineering and Software. When race drivers say they need more stick, what that really means is, 'Give us better asphalt,'" added Clements, who took ROSAN to conduct tests at the Charlotte (N.C.) Motor Speedway in late September 1997.

ROSAN has been a frequent visitor to another site, the National Aeronautics and Space Administration (NASA) base at Wallops Island, Va. Dennis Sixbey, a research engineer at TFHRC and director of the ROSAN project, said Wallops Island is an ideal test site because it contains at least 30 different surfaces.

Vehicle bumper mounted ROSAN laser
A close-up look at the ROSANv, mounted to the van using a universal mount that can be used on virtually any vehicle with a bumper.

Sixbey's research team at TFHRC included ROSAN's co-inventors, consultant Nicolas Gagarin and Jim Mekemson of Surfan Engineering and Software. Gagarin is the author of the block algorithm that allows ROSAN to analyze the laser data it collects.

Because of the algorithm, "I don't have to eat the whole cake," said Clements, making an analogy. "I can take a bite out of it and tell you if it's a good cake or a bad cake."

Others on the ROSAN team were Timothy Coppage, Ralph Wigton, and the late Loren Staunton. Sixbey fondly recalled Staunton as he explained the difference between ROSAN and traditional methods of testing pavement surfaces.

"I remember Loren on his hands and knees doing the sand patch test," Sixbey recalled.

Before ROSAN, getting on one's hands and knees was exactly what was required to test road surfaces. The tester could only measure a few centimeters of pavement at a time. And the test was subjective because the tester had to decide which tiny piece of the pavement to analyze.

"With the old test, three people could work in the same area and get different results," Sixbey said.

"Manual methods are often vulnerable to subjective decisions and variances in procedures," Sixbey and Clements wrote in a joint report about ROSAN and the new CRADA. "Selectively choosing where to take samples could easily result in unrepresentative sampling. Other than the choice of which wheel path, ROSAN doesn't give you the opportunity to select what sections of pavement to test."

Besides being slow, cumbersome, and fairly unreliable, the old test could be dangerous to the tester and inconvenient to motorists.

"Imagine somebody (on hands and knees) in the middle of the road," Gagarin said. "Traffic control is required."

ROSAN couldn't be more different. The most sophisticated model of ROSAN combines laser sensors, accelerometers, distance pulsers, bumper-mounting hardware, a vehicle-mounted beam, and a motorized trolley in one neat package. The hardware is controlled by a TFHRC-written, Windows-based program that Sixbey described as "very user-friendly."

Clements said the software can be operated with just a few keystrokes. His company was keenly interested in making ROSAN as easy as possible for the potential customer to use, he said.

The ROSAN package is mounted on the front of a vehicle, the engineer or technician controlling it pushes a few command buttons, and the vehicle's driver takes off. ROSAN can measure macrotexture, faulting, grooving, rutting, slope, and road profile at speeds of up to 120 km/h and distances of up to about 160 km.

No one on his hands and knees. No small, subjective test sites. No costly interruption of other traffic to perform the test.

"Think of ROSAN as the eyes for collecting the data that pavement engineers need. This is our target market," Mekemson said. "We have the ability to collect pavement data more accurately and cost-effectively than ever before, thanks to commercial lasers."

Roy Trent, chief of the Special Projects and Engineering Division at TFHRC, elaborated on those points and explained that devices such as ROSAN are key to widespread implementation of intelligent transportation systems (ITS).

"It would defeat the purpose of ITS if we can't reduce the interruption (of traffic that the old testing system requires)," Trent said.

The ROSAN devices will cost about $50,000 each, said Clements. Surfan has lined up about a dozen vendors to manufacture parts for ROSAN. Clements anticipates that the customers buying ROSAN will include state highway agencies, airport authorities, and private industry. ROSAN could be particularly attractive to highway agencies and airport authorities because ROSAN can take measurements without having to shut down a highway or runway.

ROSAN may have some more unusual applications, too.

"Among the 65-plus (more than 65) parties that have expressed an interest in ROSAN, one in particular caught my attention," Clements said. "We got a call from an inline speed skater who was doing some preliminary work with an Olympic subcommittee. They were looking for ways to measure and recommend suitable road surfaces for long-distance skating events."

Thanks to the CRADA, ROSAN will provide customers with a faster, easier, and safer way to measure paved transportation surfaces.

Maria Koklanaris is a freelance writer. She has been a journalist since her graduation from The Pennsylvania State University in 1986. She has been employed by The Hamptons Magazine on Long Island, N.Y.; The Connection Newspaper Group in Fairfax County, Va.; The Washington Post; the Associated Press wire service; and The Washington Times.

The Evolution of ROSAN

ROSANbp is the first in the series. It incorporates a laser sensor, accelerometer, and distance pulser in a unit that is mounted on wheels, making it light and portable. ROSANbp has two modes of operation. In the b mode, a computer-controlled trolley carries the laser sensor across a stationary reference beam. In the p mode, the entire unit is manually pushed or pulled. ROSANbp can measure macrotexture, grooving, and faulting.

ROSANv is next. It incorporates a laser sensor mounted on a vehicle bumper and can be operated at speeds up to 120 km/h, thus eliminating the need for costly traffic control. Data can be recorded continuously for distances of 265 meters to 795 meters, depending on the data collection mode. The unit can be mounted on almost any vehicle fitted with a simple bumper-mounted trailer hitch. ROSANv can measure macrotexture, faulting, and transverse grooving.

ROSANvm is a more sophisticated version of the ROSANv. A computer-controlled motorized trolley guides a laser sensor along a beam that is mounted on the front of a suitable vehicle. The beam, which is mounted transverse to vehicle travel, has three lengths - 2.1 meters, 3.5 meters, and 4.9 meters - and weighs about 46 kilograms. ROSANvm can be operated at speeds up to 120 km/h. It can measure the left wheel path, center path, and right wheel path macrotexture and faulting, grooving, rutting, and slope. Detailed transverse measurement information can be obtained while the vehicle is stopped.

ROSANvm(P) is the last and most sophisticated ROSAN. It uses FHWA's PRORUT II software to do a pavement profile, or a complete pavement surface analysis. In the future, the software will be upgraded to allow faster measurements of the left wheel path, center path, and right wheel path macrotexture. Those measurements will yield a pavement profile, as well as data on roughness, rutting, and slope.

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