CIVIL ENGINEERING SPECIAL
Improving Road Management with GIS
The Tennessee DOT undergoes a progressive and much needed technological facelift
to transition its data base into a robust GIS.
By Mary Jo Wagner

Ten years ago a request for a statewide daily traffic map from the Tennessee Department of Transportation resulted in one week of labor for the DOT staff. A request for a site-specific map such as the location of bridges statewide strong enough to support a specified amount of weight took about two weeks. Map-making mirrored the cartography of yesteryear, drafting pencils, paper, erasers and long hours.

That Was 10 Years Ago
Today that labor-intensive cartographic process is a historical footnote at the Tennessee DOT. Map-making is now a digital process-the computer screen and mouse are the necessary drafting tools.
      Today, statewide daily traffic maps and site-specific maps can be fulfilled from a desktop in less than one day.
      It's all part of a program designed to bring improved efficiency and productivity to the DOT. Called the TRIMS (Tennessee Roadway Information Management System) project, the DOT has undergone a progressive and needed technological facelift to transition its 25-year-old data base into a robust, flexible and efficient GIS.
      "TRIMS is changing the way we do business," says Tom Eldridge, TRIMS program manager.

Roads, Roads, Roads
The Tennessee DOT is charged with monitoring and maintaining about 87,000 miles of public roads, state highways and interstates throughout the state. Information such as what city the road lies in, how long it is, how wide it is, how wide the shoulder is and what type of surface it has has been recorded in a data base for each road. And the data base is continually updated with any subsequent changes. A thorough inventory of all the bridges in the state is also housed in the data base.
      Field crews study roadways for any deficiencies such as over capacity-more cars on the road than it can support-or roads with poor driving surfaces, and they tag them for improvement projects. Roads eligible for federal funding are also indicated which would allow the DOT to carry out certain projects.
      In addition to maintaining the data base, the DOT staff also performs annual traffic counts for each state highway and interstate in Tennessee. Correlations between the frequency of accidents and road conditions are also performed every year.

The First TRIMS
Although the DOT has managed to manually develop and maintain a thorough inventory of Tennessee's road networks, the ability to adequately meet the department's operational responsibilities has often been a painful process, says Eldridge.
      "We had procedures in place with our old data base system to develop the particular reports we needed, but the road we had to travel to obtain the end product was an awfully long one sometimes."
      The old system Eldridge is referring to is the TRIMS of 1973, the DOT's first computerized inventory records system. All the paper records of the road networks were manually entered into a stand-alone IBM mainframe computer.
      Eldridge says although it was a state of the art system at the time, TRIMS became more and more problematic to use. As the data base contained only tabular data, it was impossible for employees to produce maps within the system. To create maps, the relevant information had to be requested from TRIMS and downloaded to the planning division. After the maps were drawn, they'd be sent off to the mapping division where the maps would be plotted and printed.
      The system also didn't allow for data sharing throughout the department. It was housed and controlled by one department so all requests for TRIMS data had to go through certain employees, leaving the majority of the staff unfamiliar with the system. And the amount of information that could be obtained from the database was limited to a fixed set of queries.
      In addition, TRIMS was costly to update, it was not GIS-compatible and it didn't lend itself to expansion.
      By the early 1990s it was evident TRIMS had become a "dinosaur."

A Technological Facelift
Therefore, when the DOT decided it was time to design and implement a new and improved TRIMS, they had one immediate objective in mind: "We wanted to broaden the base of users to everyone who needed access to TRIMS," says Eldridge. "We wanted people to access the system directly from their desktop so they have the most current information and everyone is looking at the same data."
      With that, they set out to find the hardware and software right for them. After two years of debate, the DOT chose an Oracle database, a Windows NT platform and a suite of GIS and map-making tools from Intergraph Corp. in Huntsville, Ala. Last January, the DOT received their new system from Intergraph.
      The first step of the transformation was to transfer all the TRIMS data from the IBM mainframe to the Oracle data base. Even though the information still remains in tabular form the data base is GIS-compatible so the data is directly linked to corresponding maps. Moreover, TRIMS is based on Windows technology allowing users to run more than one application simultaneously from their desktop.
      Using GPS technology and Intergraph's Modular GIS Environment (MGE) software, the mapping division began creating "intelligent" coordinate maps to correspond with each road data set in TRIMS. That's about 87,000 miles of public roads including 14,000 miles of state highways and interstates.
      Three GPS vans have been driving the highways and interstates recording the exact location of each road and its corresponding features. By using the same intersection point as the TRIMS control network, the information is fed directly into the data base and any inaccuracies in the old data and maps are corrected.
      Eldridge says the corresponding GIS maps for the highways and interstates network are complete. The department hopes to produce the rest of the road maps by the end of 1998.
      Allowing the tabular and spatial data to talk to each other is Intergraph's GeoMedia object-oriented GIS software, the essential link between the MGE maps and TRIMS.
      "With GeoMedia users now have the TRIMS data and coordinating maps at their fingertips on one screen," says Eldridge. "They can either query TRIMS for tabular data on a specific road and then retrieve the corresponding map, or they can tag a particular road on the map and TRIMS will provide the tabular data."
      The DOT is also integrating its photo log system, a series of still-shots on 35mm film. Started 20 years ago using a vehicle-based camera that took a right-angle picture every 100th of a mile, the photo log was a useful aid but it was time-consuming to use, says Eldridge. Similar to a movie, the film had to be loaded onto a viewer and users would have to run through it to find the photo they needed.
      That too is a "headache" of the past.
      Today the photo log is tied directly to the TRIMS data base. With the MGE and GeoMedia products the staff can tag a point on a map, have the tabular data and a corresponding photo of any road in a few seconds.

The Benefits of a Whole Product
It took two years to design and implement the new TRIMS network but Eldridge says it was worth every planning meeting, every product test and every ounce of research.
      "I think one of the biggest benefits of TRIMS is it allows the department to share data," he says. "It gives everyone the same base to work from and any data they collect can be input directly from their desktop, updating the system immediately. Everyone accesses the most current data."
      Because MGE and GeoMedia can incorporate diverse data formats, Eldridge says the TRIMS network is substantially more robust, offers more flexibility and the data is more secure.
      For example, integrating other map or GIS products from other sources no longer lead to long hours to convert the data to the correct format. GeoMedia corrects the data automatically.
      "We can view any map product from any vendor," says Eldridge. "GeoMedia geo-references the data on-the-fly in the projection desired. That's a great asset because now we can not only share tabular data but also other data products within one network."
      Producing maps has gone from weeks of labor to minutes-an important benefit indeed, especially at times of crisis such as natural disasters. The DOT has been able to create maps for assessing damages in the past but delivering them in a timely manner was a problem. Eldridge believes the efficiency and effectiveness of the new TRIMS will be an important and useful aid in time of need, not only for damage assessment but also for risk prevention planning in the future.

Looking Ahead
With the flexibility of TRIMS, Eldridge predicts the network will be expanded to meet future application needs.
      One application he foresees in the near future is to enhance TRIMS role in emergencies. "We could develop pre-disaster plans for every bridge in the state. In the event that one should be closed, a re-routing plan for traffic would pop up automatically to indicate what features surround the area and where traffic should flow."
      The maintenance department is interested in using TRIMS to inventory features such as guard rails and road signs and their locations. They plan to use the data to aid them in indicating which signs or guard rails are in poor condition and then prepare appropriate budgets to replace or repair them in the future.
      The DOT plans to network TRIMS statewide giving the employees at the regional offices the opportunity to take advantage of the system. And it also has global plans as well. Eldridge says the department is interested in implementing another GeoMedia product that would allow staff to access the network remotely through the Internet.
      For now the DOT is enjoying its new-found technological freedom.

About the Author:
Mary Jo Wagner is a freelance writer, specializing in the GeoTechnologies. She can be reached by phone or fax at: 715-235-9839; or e-mail: [email protected]

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