Rethinking ADA signage standards for low-vision accessibility

Abstract

Americans With Disabilities Act (ADA) and International Code Council (ICC) standards for accessible buildings and facilities affect design and construction of all new and renovated buildings throughout the United States, and form the basis for compliance with the ADA. While these standards may result in acceptable accessibility for people who are fully blind, they fall far short of what they could and should accomplish for those with low vision. In this article I critique the standards, detailing their lack of evidence base and other shortcomings. I suggest that simply making existing requirements stricter (e.g., by mandating larger letter size or higher contrasts) will not ensure visual accessibility and therefore cannot act as a valid basis for compliance with the law. I propose two remedies. First, requirements for visual characteristics of signs intended to improve access for those with low vision should be expressed not in terms of physical features, such as character height and contrast, but rather in terms of the distance at which a sign can be read by someone with nominally normal (20/20) visual acuity under expected lighting conditions for the installed environment. This would give sign designers greater choice in design parameters but place on them the burden of ensuring legibility. Second, mounting of directional signs, which are critical for effective and efficient wayfinding, should be required to be in consistent and approachable locations so that those with reduced acuity may view them at close distance.

Gaze behavior during navigation with reduced acuity

“…After all, even a highly legible sign will offer no help if it is not seen in the first place. This issue was raised by Arditi (2017), who noted that there are no strict requirements for directional (e.g. "Bathroom →") sign placement in the 2010 Americans with Disabilities Act's Standards for Accessible Design protocol.…”

Increased letter spacing and greater letter width improve reading acuity in low vision readers

“…Several organizations for the blind and visually impaired promote the use of sans serif fonts with even stroke modulation, meaning that there is little contrast between thin and thick parts of the letters, such as Arial and Helvetica (Action for blind people, 2004; Galvin, 2014;Kitchel, 2013). There is, however, no clearly traceable evidence base for these recommendations (Arditi, 2017;Baines, 2004).…”

Luminance Contrast of Accessible Tactile Indicators for People With Visual Impairment

“…However, the evidence base for contrast requirements that are stated in current standards is unclear. For example, the 2010 ADA Standards for Accessible Design was developed in conjunction with individuals with vision loss but did not strongly consider those who wished to use their residual vision (Arditi, 2017; Bright & Cook, 2010). As another example, 30% as minimum level of sufficient luminance contrast in Australian Standards from AS 1428.4-1992 (Standards Australia, 1992) to AS 1428.4.1-2009 (Standards Australia, 2014) was determined without clear reference regarding the level of contrast people with visual impairment actually perceive as adequate to identify objects in real three-dimensional settings such as buildings or public facilities.…”