Where Rubber Meets Road in Research

The North Carolina State Highway Patrol needed help policing overweight tractor-trailers. School districts wanted a better way to map out bus routes and plan for new construction. Cities were seeking ways to make their intersections more accessible to visually impaired pedestrians. In all three situations, the Institute for Transportation Research and Education (ITRE) at NC State provided solutions.

Created by the General Assembly in 1976, ITRE initially focused on providing training programs for North Carolina Department of Transportation workers. In the succeeding decades, the center has morphed into an internationally recognized research operation that addresses a range of issues in land, air, and water transportation. "New units within the organization were created as technical needs emerged," says Dr. Nagui Rouphail, ITRE's director and professor in the Department of Civil, Construction and Environmental Engineering. "Transportation is changing so much. We're now looking at possibilities in high-speed rail and next-generation air transportation."

In ITRE's Visual Analytics, Modeling and Simulation Group, Dr. Ron Hughes leads a team of geographic information systems (GIS) experts who have developed tools to assist the Highway Patrol in enforcing regulations on big rigs. The tools grew out of a statewide database of wrecks involving tractor-trailers. "We've evolved from a focus on crashes to a focus on freight," Hughes says, noting that freight tonnage moving through North Carolina is expected to double by 2020. As the trucking industry moves toward "more productive" vehicles — longer and often heavier — the concern for safety on rural roads increases. Rural roads are more susceptible to pavement damage from overweight trucks, he says, and the risk of fatal crashes can be two to three times higher than on an interstate.

"We're trying to help (the Highway Patrol) be more effective at keeping our roads safe."

Hughes' team overlays the crash data — it's broken down by time of day and day of week as well as location — with an array of other GIS information, such as the locations of smaller bridges, where and when troopers stopped rigs for inspections, and the frequency of citations for driving or weight violations. The Highway Patrol officers can use the information to see how their enforcement efforts match the needs in their region. The ITRE researchers are using risk analysis to pinpoint "hot spots" that have statistically significant clusters of wrecks and are aligning their data with GPS devices in troopers' cars for more precise mapping. "There are only 300 troopers in North Carolina to handle motor carrier enforcement," Hughes says. "We're trying to help them be more effective at keeping our roads safe."
The work done by Jeff Tsai and ITRE's Pupil Transportation Group helps North Carolina school districts use school buses more efficiently. Officials used to map their bus routes by sticking pushpins in a map to show where students lived and then running a string from one pin to the next. ITRE helped incorporate all addresses statewide into a GIS database and then worked with a software developer to implement a system that determines the combination of routes within a district that requires the fewest buses and saves the most time and fuel getting students to school and back home. Since lawmakers required all North Carolina districts to adopt the computerized system, it has cut the number of buses needed statewide by up to 890 each year.

ITRE has developed other applications for GIS data, including helping districts set attendance zones and find sites for new schools. Wake County school officials, for example, asked the institute to help determine their construction needs for a $1 billion bond issue in 2007. Researchers used mathematical models and decision-science tools to map growth projections and showed officials areas where schools would be needed in the future. ITRE is now doing similar growth forecasts for more than 30 school districts statewide and for districts in South Carolina and Mississippi. "Once you know where students live, it's easy to grow from just transportation into efficient planning," Tsai says. "There are hundreds of ways to draw school maps, so you look at data layer by layer to make your decisions."

Concerned about the ability of people with disabilities to navigate complex intersections, Rouphail is leading an ITRE team trying to make decisions easier for visually impaired pedestrians at intersections with roundabouts. The configuration of such intersections makes it difficult for pedestrians to judge by sound when it is safe to cross, but installing traffic signals would defeat a roundabout's ability to keep traffic moving. So the ITRE researchers have examined a variety of solutions, from raised crosswalks that force drivers to slow down to rumble strips that provide an auditory signal to blind pedestrians that a vehicle is approaching. "If we slow vehicles down," Rouphail says, "the propensity of drivers to yield increases without stopping and delaying traffic."

"We're now looking at possibilities in high-speed rail and next-generation air transportation."

The research team also used funding from the National Institutes of Health to develop an automated yield-detection system that uses a combination of video cameras and a computer algorithm to determine when cars have slowed enough entering or exiting a roundabout for a pedestrian to cross. The system is activated when someone pushes a button at the crosswalk, and it provides a voice signal when the path is clear. "The yield-detection system allows pedestrians to take advantage of natural opportunities in the traffic flow to cross," Rouphail says. Students at the Governor Morehead School for the Blind in Raleigh were enlisted to test the system at a roundabout on NC State's campus, and the researchers found that they crossed about 30 percent more often with the system telling them that cars had slowed for them. "ITRE addresses many needs," Rouphail says. "We are literally where the rubber meets the road in terms of research."

 

Drs. Ron Hughes, left, and Nagui Rouphail work with international, national, state, and local agencies to address transportation-related problems.

A map created by ITRE's Visual Analytics, Modeling and Simulation Group depicts Highway Patrol enforcement of tractor-trailer regulations relative to truck crashes and fatalities. Darker green areas are "hot spots" for wrecks, while the maroon circles show places where troopers are inspecting trucks and citing drivers.

Visually impaired pedestrians have difficulty navigating intersections with roundabouts because it's hard for them to judge by sound when it's safe to cross.

Jeff Tsai and ITRE's Pupil Transportation Group help school districts plan for growth in addition to finding the most efficient way to get students to and from school.