U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
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The purpose of this document is to help Federal, State, Tribal, and local agencies understand the benefits of utilizing interactive, three-dimensional (3-D) visualization to assist a road safety audit (RSA) team in performing a safety performance examination of potential roadway designs. This effort included performing four pre-construction stage RSAs in four different regions of the country that incorporated 3-D visualization in the standard eight-step RSA process (see Table 1).
Table 1: Pre-construction Stage RSAs Conducted Using 3-D Visualization
Location and Host Agencies | RSA Design Stage | Facility Type | Focus |
---|---|---|---|
Middletown, RI; Rhode Island: Rhode Island Department of Transportation (RIDOT), Aquidneck Island Planning Commission, US Navy | Preliminary Concept (0 - 1%) |
Two-lane limited access connector road |
New roadway
and alternative intersection designs. |
Belgrade, MT; Montana Department of Transportation (MDT) | Conceptual (1 - 25%) |
Expressway interchanges |
New Interstate highway access. |
Prince William County, VA; Prince William County
Department of Transportation, Virginia Department of Transportation (VDOT) |
Advanced (90%) |
Two-lane road widened to four lanes |
Roadway widening and curve flattening and realignment. |
Perris, CA; Riverside County Transportation Commission (RCTC), California Department of Transportation (Caltrans) | Preliminary (40 - 80%) |
Expressway interchanges; multilane arterial | New complex interchange design. |
Three-dimensional models of the proposed concepts and designs were developed using digital terrain models, design surface models, associated 2-D or 3-D computer-aided design (CAD) files, and other information necessary to create a detailed rendering of the proposed roadway and surrounding environment. This included traffic control signs, pavement markings, lane configurations, major landscaping, roadside appurtenances, traffic signals, and other items within the right-of-way to render a realistic visualization of the roadway and its environment. The 3-D models were exported to a 3-D PDF format that allowed them to be viewed using Adobe software that is both free and readily available to the general public. Furthermore, the 3-D PDF controls were easy to use for someone with basic computer skills. The user could easily rotate 360 degrees while virtually "walking" or "driving" through stations spaced 100 feet apart along the proposed alignment. Using the technique of creating the model in the 3-D PDF format enabled the RSA team and roadway owner to share and review the 3-D models to ensure their accuracy.
The use of this tool during the RSA allowed team members to visualize the project designs and identify elements that may pose a safety concern to future road users. These elements can then be further discussed and evaluated during design phases, allowing changes to be more easily made to plans rather than after the roadway has been constructed.
Three-dimensional visualization can be a useful tool in assisting RSA teams to make a more thorough assessment of safety. When used effectively, the 3-D model is a tool that will save the RSA team time and yield a heightened awareness of safety issues related to the design project. In general, the benefits associated with 3-D visualization include the following:
Moving forward, techniques are continually advancing the ability to utilize 3-D visualization. Future tools will be more efficient and graphic capabilities more advanced, which will allow the further integration of 3-D visualization in the RSA and other safety processes. It is recommended that 3-D visualization continue to be incorporated within RSAs of future/potential construction projects.
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