See it before it's built: visualization technology is cheaper, faster, and more precise than drawing proposed road projects by hand

Public Roads, May-June, 2002 by Richard E. McDaniel

Imagine your client is the park superintendent for a national park. To help move visitors in and out of the area, a new road needs to be built to augment the existing one. You propose three design options: a bridge that allows for an arch design, a high-clearance bridge requiring long columns, or a low-clearance bridge. The client now needs to decide which design would suit the park best.

Wouldn't it be nice if the client could actually see the bridge--exactly as it would look after construction and against the actual backdrop of the park--before making a decision?

The Federal Highway Administration (FHWA) provided precisely that service for the National Park Service's Natchez-Trace Parkway in Mississippi. The park people were interested in a bridge spanning historic Old Agency Road. But residents living nearby were concerned, among other things, about the impact of constructing a bridge over this tree-lined roadway. Paul Schneider, John Seabrook, and myself, all with FHWA's Eastern Federal Lands High Division's (EFLHD) Location Branch, showed them a dozen different options--using different bridge colors and types. We also showed them what it would look like without any landscaping, and what it will look like in 5 years after vegetation has grown.

These days, clients do not need to attempt to visualize designs in their minds, and they do not have to pay a fortune to obtain artist's renderings of the various options. All they need to do is have their tech folks produce a design visualization for the project.

Get the Picture

Design visualization (DV) technology enables engineers to depict how facilities like bridges, roadways, side-walks, and buildings will look after they are completed. The DV images can be displayed on computer screens or in large, high-resolution color photographs. To do this, the engineers match a photograph of the construction location with a three-dimensional (3-D) computer-generated model of the proposed design. What emerges is a composite view of the proposed highway facility superimposed on the photograph of the construction location. In addition to still pictures, 3-D animation software makes DV video simulations possible as well.

DV can be used for any aspect of roadway design, including construction of new bridges and roadways and modification of those facilities. Although the processes used in DV have been available for some time, the technology has become more feasible only in recent years--thanks to rapid advances and filling costs in computer technology. Before the requisite technology was available, the only way to produce visualizations was for an artist to draw them by hand. Today, with high-end graphics workstations and software available at reasonable costs, such manual work is no longer required. And computer technology allows for much greater precision compared with hand-drawn simulations.

Connecting with the Layman

DV technology not only helps engineers during their planning process, but also it serves as an effective way to communicate clearly design implications to non-engineers. Thanks to this technology, highway engineers now are able to take their composite drawings to public meetings and present them to non-engineers with ease.

Engineers can show different alternatives for various types of bridges, alignments, and other possibilities and provide decision-makers with a better understanding of what the completed facility will look like before they actually make a decision. This technology provides decisionmakers with better information to base their decisions on.

The layperson, even when shown sophisticated 2-D engineering drawings, often has difficulty conceptualizing what the constructed facility would look like. Making decisions without fully grasping the design implications often causes problems down the line. After construction work has started, making changes is either impossible or very expensive.

Dan VanGilder of FHWA's EFLHD Technical Services Branch witnessed an excellent example of the impact of DV technology on decision-making during a road project at Manassas Battlefield National Park in Manassas, VA. The project involved lowering the grade of a section of a roadway with poor sight distance. Early in the development of the project, the engineers explained to the local residents that the present road was hazardous because motorists driving down the hill could not see traffic stopped at the intersection.

Before VanGilder's DV presentation, citizens in the area were not convinced that the project was necessary. But then he showed a video simulation of a vehicle driving down the hill as it currently was configured, demonstrating that motorists could not see vehicles at the intersection. After that, he showed a DV simulation with the grade lowered, which demonstrated that this improvement would enable the driver to see the intersection clearly. After the presentation, the viewers said that they appreciated the safety concerns and acknowledged that the project would benefit the local population. The DV demonstration thus became a crucial factor in obtaining approval for the project, which has since been completed successfully.