PROBLEM/SITUATION: Florida's State Road 60 was a dangerous, narrow stretch of road motorists would go out of their way to avoid. Yet expansion was limited because it passed through environmentally sensitive areas.
SOLUTION: Use of GIS
software provided an easier, faster process for designing alternate routes while
ensuring sensitive areas remained protected.
JURISDICTION: Florida Department of Transportation.
VENDORS: Greenhorne & O'Mara Inc., Intergraph Corp., Bentley Systems Inc., HMR Inc., Hewlett-Packard.
CONTACTS: Eddie Yue,
consultant manager, Florida DOT, District IV
State Road 60 across rural central Florida's Indian River County is a 25-mile corridor through sub-tropical swampland, endangered-species habitats, sensitive wetlands, citrus orchards and cattle ranches. Exotic and diverse as the area may be, the narrow, two-lane road through it is a dicey affair with narrow shoulders, ditches on either side, and heavy traffic from agricultural trucks. It has a high incidence of traffic fatalities, and although east-west corridors in Florida are few, even locals go out of their way to avoid this one.
According to Edward Yue, Florida Department of Transportation's (FDOT) project manager for District IV, "Indian River County surveys indicate that nearly 80 percent of the residents are afraid to travel SR 60 west of I-95. In 1991, 15,000 county residents signed a petition favoring improvement, one of the largest petitions for road improvement in recent state history."
Now, SR 60 is about to change. Recently designated by FDOT as a main artery in the Intrastate Highway System, it is to be expanded to four lanes with a center divider. Yue stated that, in addition to being safer and less vulnerable to flooding, an improved SR 60 will promote greater sharing of resources between Florida's two coasts. It will also serve as an effective east-west evacuation route in times of disastrous hurricanes.
Before actual construction begins on SR 60, however, the Project Development and Environment (PD&E) Study, now 70 percent complete, must go through public hearings and be approved by various state and federal agencies. Given the sensitive nature of the area, FDOT guidelines for the project required extensive environmental and social impact studies; engineering designs for three 25-mile alignment alternates, impact assessments for each; and a proposal for a preferred, fourth alternate comprising the best characteristics of the three. Deliverables are to include finished drawings in digital and hard-copy formats of each 25-mile alignment, scaled to 1 inch =100 feet.
The consultant for the project is Greenhorne & O'Mara, headquartered in Greenbelt, Md. According to Tony Drescher, project manager of G&O's West Palm Beach office, the firm would not have taken on a project with this length of roadway had it not already developed a rapid, much-simplified design process exploiting leading-edge GIS technologies. G&O first used the process in the recently completed PD&E study for the expansion of a five-mile section of Miami Garden Drive, in North Miami, from four lanes to six. "In comparison to earlier methods," Drescher said, "the new process cut project time by a very conservative 40 percent."
THE DESIGN PROCESS
At the core of the process are Microstation and Descartes, the only software systems used. Microstation is a CAD graphics driver for various GIS applications, and can operate throughout a local-area or wide-area network. Descartes is a high-speed GIS software capable of digitally linking hundreds of separate raster (electronic) images into a single file. SR 60 project personnel can pan across a "seamless" map of the entire 25-mile corridor; pull up any section and make changes; create layers of different attributes; manipulate color schemes; change scales, and to a limited extent, alter the raster image itself.
An important feature of Descartes, explained G&O Senior CAD Technician Lanny Brady, allows users to selectively superimpose transparent layers of spatial data over the raster image of the aerial. Engineers plotting alignments on the design layer can see wetland delineations or property boundaries on other layers, as well as the raster image beneath.
Drescher said the feature provided enormous design flexibility. "Having that background image while designing lets me see that if I move this line here, it's going to go through these houses or across that wetland, so I'll try shifting it this way because there's a vacant lot on the other side of the road -- different scenarios like that. We had many areas with sensitive wetlands that we deviated the alignment from to avoid impacting. The software gave us the flexibility to experiment with curves, try different ideas, and immediately see what the impact would be."
Brady believes a small shop could get into this as easily as a large firm. "There's nothing cost prohibitive about the process; it can all be done on a stand-alone PC. We just exploited some GIS applications to come up with an easier, faster process of producing quality file products."
For the SR 60 PD&E study, about 40 positives of aerial photographs were raster-scanned into TIF files (a common raster image format). G&O used Descartes to convert the files into a single image of the entire 25-mile route. "It's a very quick process," Brady said. "As soon as we have it in a format Descartes can use, we put it in the same file as our topographic baseline survey and match up the coordinates. When everything lines up, the topographic file lies right on top of the background image."
"The way we set up our files," Drescher explained, "makes it relatively easy for a number of people to work on the same project simultaneously. Design changes by the engineer are reflected over to the CAD technician, who may be working on annotations or color coding. At the same time, the survey and environmental departments can be looking at the same files to see if there are changes the project manager may need to make. The process really facilitates communication."
"Users of the design file can always get updates," Brady added. "With Microstation, you just press a reload button, the screen flashes, and a few seconds later the image is back up with the latest changes."
When the design phase of an alignment segment is completed, the CAD technician adds the data from associated files -- baselines, utilities, annotations, attributes, etc. When all three alignment alternates are complete, the entire route is divided into four segments, and each one is analyzed for the best alignment characteristics. These are linked together to create a 25-mile, preferred alignment for the route.
Final plans of the PD&E study are produced in digital format and in color, on 11 X 17 sheets, from a Hewlett-Packard 650 plotter. At a scale of 1 inch=100 feet., there are about 300 drawings. For public hearings, however, the proposed alignment for the 25-mile route will be plotted out on four, 11-inch X 100-foot rolls (one for each alternate) and displayed on walls or laid out parallel on tables. Brady said that a similar display for public hearings on the Miami Garden Drive project was "very successful; people could easily see how the alignment would impact their properties. The DOT project manager for Miami Garden Drive said it was the smoothest public hearing they'd ever been through."
Yue pointed out that although
the public hearing is scheduled for May 1996, public information meetings have been held already. "Since the public could visualize all the alternatives clearly, the project was favorably received. Electronic images of the aerial photographs show very accurately the impacts associated with the improvements. The ability
of G&O to produce exhibits of the images in various sizes has made it easier
to communicate with the public.
"CAD and raster technology," Yue added "make it possible for the firm to quickly incorporate ongoing changes requested by various agencies. It also allows new alternatives to be evaluated with greater accuracy. Although it is difficult to estimate at this time, FDOT has seen a substantial time savings of six to 12 months. The financial benefits will really be seen in the final design phase."
Pentium PCs with 16MB to 32MB of RAM, running at 60 MHz to 133MHz. Hewlett-Packard 650 Plotter with 68MB of memory.
Microstation is the nucleus graphics driver for many GIS applications. It also allows the application to be run in LAN or WAN client/server settings. Microstation is jointly owned by Intergraph Corp. and Bentley Systems Inc.
Descartes is a product of HMR Inc., of Beau Port, Quebec, Canada. Cost of the Descartes engineering package used by G&O is under $3,000.