In 2015, in response to a study conducted by the National Cooperative Highway Research Program (NCHRP), the FHWA adopted new guidance on how to conduct an assessment of the visual impacts caused by highway projects. The new guidance replaced the agency’s original VIA process published in 1981. The older guidance was premised on the concept that scenic beauty was an attribute inherent in the landscape. It assumed that the less a landscape had been modified by human intervention—that is, the more natural it was—the greater its scenic quality. Although the 1981 FHWA VIA process recognized that people reacted to changes in the landscape, it strictly defined impacts to visual quality only as changes to existing visual resources.
The revised 2015 FHWA VIA process was premised on a very different assumption of the nature of the perception of visual quality and, subsequently, visual impacts. The new process was based on the concept of transactional perception, a concept that our perception of the environment, and consequently our assessment of visual impacts, is a result of our interaction with the environment. Visual quality was an experience that could not be isolated in the nature of the environment nor strictly “in the eye of the beholder.” It isn’t made up but it isn’t concrete, either. It is the nebulous interaction between viewers and visual resources.
The 2015 FHWA VIA process has four phases—Establishment, Inventory, Analysis, and Design. The Establishment Phase identifies the visual attributes of the proposed project, the legal and customary visual preferences of viewers, and the geographic Area of Visual Effect (AVE). The Inventory Phase identifies the visual resources as being from the natural, cultural, or project environments. It also identifies viewers as either neighbors or travelers. It concludes by defining the experience of visual quality as a composite of three components: 1) the viewer’s perception of the harmony of the AVE’s natural resources, 2) the perceived order of its cultural resources, and 3) the coherence of the resources that were used to build the highway. The Analysis Phase begins by identifying the compatibility of the visual character of the proposed project with the visual character of the surrounding landscape. It continues by identifying the sensitivity viewers will have to the changes to visual resources the project will cause. It concludes by assessing if the project will adversely or beneficially affect the experience of perceiving natural harmony, cultural order, and project coherence of neighbors and travelers. The Design Phase completes the VIA by determining methods for mitigating adverse impacts and advancing beneficial impacts to visual quality.
Churchward, Craig, "Visual Impact Assessment: New Guidance from FHWA" (2019). Visual Resource Stewardship Conference. 7.