Decision Support System developed to aid in Florida’s highway planning
The Florida Department of Transportation recently gave CUTR the task of “sharpening” one of its computer tools used in the planning of the Florida Intrastate Highway System (FIHS). In response to this task, CUTR improved and modernized the Decision Support System, a state-of-the-art software system for transportation planning. Established by the legislature and the Governor in 1990, the FIHS is a system of high-speed, high-quality highways that would enhance travel between Florida’s major regions and cities, including connections to the other continental states through the neighboring states of Georgia and Alabama. The FIHS highway facilities include the Interstate System, Florida’s Turnpike, expressways, and other major highways throughout the state that provide interregional mobility.
Despite the word "highway" in its name, the FIHS is, in fact, a multimodal and intermodal transportation system. It connects multi-modal facilities like parallel transit and rail facilities and encompasses highways, connecting intermodal facilities such as airports, rail passenger and freight terminals, seaports, transit stations and stops, and truck terminals.
History of the Decision Support System
“It was pretty clear from the beginning that our planning tools couldn’t really meet the challenge of planning this new (transportation) system,” said Sheppard Martin, FDOT Project Manager. “What we needed was a whole new way of doing the business of planning. That’s when the concept of the Decision Support System (DSS) was born.”
Originally, the DOS-based computer application, called DSS-1, divided Florida’s Interstate Highways into sections, enabling analysis of traffic congestion, safety, pavement condition, and economic development potential of the surrounding area so the areas needing the most attention could be identified through a ranking. The analysis was based on data received from FDOT’s internal computer systems. A statistical method, similar to grading an academic test on a curve, was used to evaluate congestion and the other factors separately. The relative importance of each factor was reflected by user-supplied weights. This weighted average was, itself, graded on a curve, where scores ranged from 0 (low priority) to 100 (high priority).
At the start, attention was focused on the production of a list of priority highway segments for further study. Production of screen or printed maps, although desirable, was considered a secondary priority. This was largely due to the fact that mapping and drawing software that was available in 1991 was slow, expensive, and not very flexible. For these reasons, FDOT elected to write its own map display program. It was at this time that the unique DSS prototype became fully operational and known as DSS-1.
Immediately following, DSS-1 was demonstrated for FDOT management. The “split-screen viewer” feature, which allowed two different maps to be viewed side-by-side in a synchronized manner, helped convince them of its usefulness and was quickly approved for use in the planning of the Interstate portion of the FIHS.
In 1992, a second prototype, DSS-2, was authorized. This version of the system was to be extended to all FIHS highway corridors and was required to conform to the requirements of the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA). DSS-2 included a fifth ranking factor—a measure of inter-modal connectivity between FIHS corridors and airports, rail passenger and freight terminals, and seaports. It also had additional refinements added to the mapping program and improvements that added to its speed and accuracy.
After successful demonstration for FDOT management, DSS-2 was approved for use in the planning of all parts of the FIHS and released to FDOT District Offices.
CUTR’s role
CUTR has been an active partner with FDOT in the refinement process of the Decision Support System since 1995. This research effort was CUTR’s first major software development project, as well as its first geographic information systems (GIS) development project. CUTR’s primary contribution to this ongoing effort is the newest version of the system, DSS-3.
DSS-3 is a Windows version of the software system. This graphical user interface allows the mapping program not only to display information but also to serve as the overall control center for the entire software system. The system is a user-friendly program in which complex operations are controlled by menus and simple input forms. This enables users to complete the movement of simple, rapid, and meaningful transportation planning tasks.
These users now have the ability to perform a planning analysis of the FIHS system by filling out one of the aforementioned forms. Weights for the five ranking factors (traffic congestion, safety, pavement condition, economic development potential, and intermodal connectivity) that reflect potential policy goals are entered first. For example, a policy that emphasized equal importance for safety, preservation of infrastructure, and congestion relief, to the exclusion of economic development potential and intermodal connectivity, would require entering weights of 0.33 each for safety, congestion, and pavement condition, while entering 0.00 for economic development potential and intermodal connectivity.
The form also allows the user to select an analysis year between 1995 and 2020. Year 1995 is the "base year" for which actual data have been included from several of FDOT’s in-house computer systems. A built-in traffic forecasting technique estimates traffic volumes in the subsequent years (1996-2020). The user also has the ability to include or exclude projects in the current FDOT Work Program with the click of a mouse. Upon completing the form, the user begins the analysis by clicking another button.
On most desktop computers, DSS-3 performs its ranking and produces a color-coded map within 10 seconds. The colors indicate the grade that the system has assigned to highway corridors, given the user’s weights, and related information. Highways shown in green indicate a grade under 33 out of 100; these segments represent emerging needs and may require attention now or in the near future. Grades above 67 are shown in red; these segments represent current needs and require immediate attention. Line styles are also used to differentiate between the three classes of highways as an aid to users with color vision problems.
Complete background information for any highway segment can be displayed by pointing and clicking the mouse. The map has both zoom in and zoom out functions and a wide variety of labels can be added or removed from the map. DSS-3 saves the ranking information for each analysis for display at a later time. Additionally, DSS-3 can produce paper maps, save screen captures, and export files for use with other GIS and drawing software. The split-screen viewer also is included in the Windows environment and has similar features.
Progressive mapping features
CUTR developed two powerful features that are unique to DSS-3. The first of these is a tool for combining individual sections of highways into regional or even cross-state corridors. The user can operate the mouse like a transparent marker to highlight the corridor to be analyzed. The system calculates summary statistics for the highlighted roadway segments and stores an identifier for future reference. This tool saves labor for FDOT over other manual and automated tabulation methods. CUTR is currently exploring other uses for this selection tool, including the designation of bus routes and utility lines that follow city streets and other line features.
The second tool developed by CUTR for DSS-3 is a “chalk-talk” tool. This tool allows on-screen drawing or highlighting, similar to that used during televised broadcasts of professional football games. This tool is particularly useful when DSS is used with a screen projection display.
Future directions
Work is currently under way on DSS-4. Among the new features in this version will be the ability to import information from FDOT’s transportation demand modeling tool, the Florida Standard Urban Transportation Modeling Structure (FSUTMS). This feature will allow DSS-4 to use either its internal traffic forecast or a traffic forecast developed by a Metropolitan Planning Organization (MPO). The processing of this planning data requires the conversion of a FSUTMS map graphic to a precise geographic representation in DSS-4. A pattern recognition process similar to that used for computer vision is used to read a FSUTMS map. DSS-4 will include improved report capabilities, enhanced map graphics, and several other innovations.
The lessons learned in the development of DSS-3 and DSS-4 have resulted in spin-off projects at CUTR. One example is the Florida Transportation Atlas, which was included with the CD-ROM release of the Florida Transportation Almanac and Atlas in 1996. The Atlas map viewer provides an introduction to the world of GIS at many levels. This includes a Visual Basic source code that illustrates the fundamental elements of computer mapping.
CUTR is dedicated to the use of GIS technology for complex geographic analysis and the production of high-quality paper maps. However, CUTR is also dedicated to the concept that these systems need to be accessible and meaningful to users. In both the Decision Support Systems and the Florida Transportation Atlas, CUTR research shows that geographic information systems perform best when they are developed and operated at a human scale. For further information about the Decision Support System, contact Dr. Richard Stasiak, CUTR’s GIS and Data Program Manager, at stasiak@cutr.usf.edu or call (813) 974-3120.
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