14 CFR Parts 382 and 399; 49 CFR Part 27 - Nondiscrimination on the Basis of Disability in Air Travel: Accessibility of Web Sites and Automated Kiosks at U.S. Airports - Preamble

Display Screens

The Department did not ask specific questions but received a few comments about the proposed specifications for display screens.

Comments: The Trace Center suggested that we change the requirement for display screens such that they must not only be visible, but also readable, from a point located 40 inches (1015 mm) above the center of the clear floor space in front of the automated kiosk. Several commenters requested that the language concerning the required contrast of characters with their background on visual displays be changed from “either light characters on a dark background or dark characters on a light background” to “with a minimum luminosity-contrast-ratio of 3:1.” Trace Center requested that we require a higher contrast ratio of 4.5:1 for characters that are less than 14-point.

DOT Decision: We have accepted the suggestion to require display screen characters and background to have a minimum luminosity-contrast-ratio of 3:1. This ratio is consistent with that specified in the WCAG 2.0 Success Criteria 1.4.3 on minimum contrast. Combined with the requirement for characters on the display screen to be in sans serif font and at least 3/16 inch (4.8 mm) high (based on the uppercase letter “I”), the 3:1 contrast ratio will satisfy the success criterion at Level AA. (For further clarification of this requirement see the WCAG 2.0 definitions for “contrast ratio” and “relative luminance” found at: http://www.w3.org/TR/WCAG20/#contrast-ratiodef and http://www.w3.org/TR/WCAG20/#relativeluminancedef.)

Regarding display screen visibility, we have not accepted the suggestion to require display screens to be readable from a point located 40 inches above the center of the clear floor space in front of the kiosk. The proposed requirement that the display screen be visible from a point located 40 inches above the center of the clear floor space essentially means that the display screen must not be obscured from view at that height. A requirement that the display screen be readable from that height would not be practicable since “readability” is a function of many factors, including screen characteristics (e.g., font size), ambient conditions (e.g., lighting), and each potential reader's visual acuity when viewing the screen at a given distance from the eye.