Most people rely
on paper maps to guide them to a destination, but some researchers use
geographic information systems (GIS) tools to make maps to improve transportation.
GIS is a computer system that assembles, stores, manipulates, and displays
data identified according to their geographic locations. GIS technology
can be used for scientific investigations, resource management, and
development planning.
At ORNL's Center
for Transportation Analysis (CTA) in the Energy Division, Bruce Peterson
and Frank Southworth have developed a GIS-based research tool used by
the U.S. Department of Transportation (DOT), state DOTs, private companies,
and universities. It is called the North American Intermodal Freight
Network Model. ORNL researchers have used the model to estimate the
annual ton-miles of freight on U.S. roads, waterways, and rail lines
in support of the U.S. Census Bureau's 1997 Commodity Flow Survey.
For this project,
Peterson developed algorithms that calculate the shortest route and
the least costly combination of modes (truck, barge, rail car) for moving
freight rapidly and economically from one zip code area to another in
the United States. Some 5 million such routes were simulated in support
of the 1997 Commodity Flow Survey.
"Separate truck,
rail, and waterway networks have existed for a long time," Peterson
says. "We have come up with a unified network that models the U.S. transportation
infrastructure by including all freight-carrying modes."
"State departments
of transportation could use the network to simulate the flow of traffic
over their major highways, rail lines, and waterways," Southworth says.
"These flow patterns might then be used to estimate the need for new
investments in transportation infrastructure."
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This
GIS map shows areas of the United States where truck traffic is
particularly heavy (denoted by thickness of colored lines).
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S. M. Chin of CTA uses
GIS tools to study the movement of freight between airports; truck and
rail terminals; and sea, lake, and river ports. He identifies bottlenecks
where freight changes hands from one mode of transportation to another,
such as the traffic congestion around Los Angeles International Airport.
Displays of data on GIS maps suggest where resources should be invested
to reduce congestion and eliminate bottlenecks to expedite truck-air,
truck-rail, truck-water, and rail-water transfers of freight.
Some of ORNL's GIS researchers
may move to the GIS laboratory at the National Transportation Research
Center. The director of the laboratory is Don Alvic of the University
of Tennessee (UT), and the laboratory is staffed by UT researchers.
One project under way there is to use data from county departments of
transportation to determine the best places to locate proposed new roads.
The UT researchers examine the characteristics of the current highway
system, interchange accessibility, bridge weight limitations, and land-use
considerations before recommending possible locations for new routes.
"Our GIS lab produces
data similar to the Internet maps from search engines, but these maps
are more complicated," Alvic says. "Our software will find the shortest,
fastest route between two points. Military transportation planners,
for example, may want the best highway route that allows them to avoid
travel through some cities and over certain bridges. If they are shipping
biological and chemical warfare materials for disposal, they may want
to find a route that passes through areas of very low population, to
minimize the chances of accidental exposures."
GIS studies by
ORNL and UT researchers are helping to put East Tennessee on the transportation
research map.
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Related Web
sites
ORNL's
Center for Transportation Analysis
ORNL's
Energy Division
