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Accessibility: Section 508

The Department of Transportation (DOT) is committed to complying with all statutory requirements to ensure that web content is more accessible to people with disabilities.  We make a concerted effort to meet the standards of Web Content Accessibility Guidelines (WCAG) 2.0, and Section 508 of the Rehabilitation Act of 1973, as amended.  (Web "content" generally refers to the information in a web page or web application, including:  natural information such as text, images, and sounds code or markup that defines structure, presentation, etc.). For more information, read DOT's Digital Accessibility Statement.


In 1998, Congress amended the Rehabilitation Act of 1973 to require Federal agencies to make their electronic and information technology (EIT) accessible to people with disabilities. The law (29 U.S.C. § 794 (d)) applies to all Federal agencies when they develop, procure, maintain, or use electronic and information technology. Under Section 508, agencies must give disabled employees and members of the public access to information that is comparable to access available to others. The United States Access Board discusses the Section 508 law and its responsibility for developing accessibility standards for EIT to incorporate into regulations that govern Federal procurement practices.

Section 508 establishes requirements for electronic and information technology developed, maintained, procured, or used by the Federal government. Section 508 requires Federal electronic and information technology to be accessible to people with disabilities, including employees and members of the public.

An accessible information technology system is one that can be operated in a variety of ways and does not rely on a single sense or ability of the user. For example, a system that provides information only in visual format may not be accessible to people with visual impairments and a system that provides information only in audio format may not be accessible to people who are deaf or hard of hearing. Some individuals with disabilities may need accessibility-related software or peripheral devices in order to use systems. Section 508 requires systems to work with the accessibility-related solutions.

Section 508 applies to a broad variety of electronic and information technology including:

  • web pages and internet or intranet based services and applications;
  • software and applications (off-the-shelf and custom developed);
  • telecommunications including telephone systems, telephones, voice mail and interactive voice response systems, and fax machines;
  • duplication, printing and copying equipment;
  • stand-alone stations (or information kiosks);
  • multimedia presentations including video conferencing, television broadcasts, training media;
  • support services, and documentation.

The following are a sample of the many ways in which Section 508 standards are applied to DOT and Operating Administration (OA) websites:

Accessibility (508):  Acceptable Uses of Flash

DOT webpages are designed to avoid causing the screen to flicker with a frequency greater than 2 HZ and lower than 55 HZ.

Flash format (animation, video) is virtually impossible for screen readers to navigate, and will only be used on our website when necessary.  When Flash animation is used, it will not automatically play the media or show the graphic when your page loads—you will be able to start and stop the media or click to access the graphic if you want to view it.

In addition, when providing content in Flash format, DOT will conform to accessibility (Section 508) best practices, such as providing users with a non-Flash (HTML) or accessible Flash version (e.g., with tagging for readability by screen readers).

Accessibility (508):  Accommodation

DOT allows the use of an accessibility accommodation with approval where the application of current Section 508 standards is not feasible, not helpful and/or not practical.

General categories and examples of content that may be appropriate for an Accessibility Accommodation include:

  • Excel computational spread sheets containing program modules and macros developed to perform automated analysis or to draw in data sets from external or legacy databases.
  • Password-protected sites
  • Multilingual PDF documents using non-Western characters
  • Complex images and PDF tables, including static images and those supported and detailed narratives
  • Complex math, physics, and chemical notations
  • Large or complex tables, given a waiver based on consideration of:
    • Importance of the document
    • Size and nature of intended audience
    • Expectation that disabled persons would need access
    • Complexity of the table
    • Size of the table
  • Scanned written or poor quality historical publications/materials scanned to a digital archive
  • Archived legacy files.
  • Translated files (presented in a language other than English).

Accessibility (508):  Color and Contrast

DOT and Operating Administration web content is reviewed to ensure that users can read text that is presented over a background. Visual indicators are used to distinguish and organize content, and a color contrast checker is applied to confirm that text and background colors have enough contrast.

Accessibility (508):  Documents

DOT is committed to ensuring all content is accessible to our customers with disabilities. The content management system has an automated featured that allows us to monitor documents that are published to the web. DOT content authors are required to:

  • Verify that their documents being uploaded to our website is 508 compliant.
  • Provide a current and responsive contact for customers with disabilities to receive the information in an alternative format.

Accessibility (508):  Excel Presentations

DOT evaluates each Excel table for Section 508 compliance.  For simple data tables, row and column headers are identified.  For complex data tables, markup is used to associate data cells and header cells for data tables that have two or more logical levels of row or column headers.

Accessibility (508):  Email

DOT ensures that all broadcast emails and emails generated by web applications (“Email this page,” etc.) are accessible to people with disabilities. This standard applies to both internal and external emails, as well as all associated attachments, including graphics, audio, and video.

Accessibility (508):  Skip Navigation

All DOT and OA web pages provide a method for skipping repetitive navigation. The skip navigation is available to screen readers and has keyboard access. Sighted users are able to scan a page and quickly select a section of the page to read.

Accessibility (508): Video/Multimedia Content

All DOT web-hosted videos are captioned to ensure equal access and ease of use for those persons using Assistive technologies. The captioning requirement covers all videos and multimedia files, including all formats over the air broadcast, CD or DVD, and web multimedia (such as video podcasts, webcasts, Flash, or other animation), whether produced internally or externally, including video produced by partners if federal funds are used. It is not permissible to provide stand-alone transcripts in lieu of video captioning.

DOT provides a text equivalent for every non-text element (e.g., via “alt,” “longdesc,” or in element content) for Podcasts and other sound files.  Text transcripts are included for podcasts or other audio-only files, such as .mp3’s.  Alternatively, DOT provides an HTML page containing the transcript, or links to a separate text file.  When a DOT web page requires that an applet, plug-in, or other application be present on the client system to interpret page content, a link to a plug-in or applet that complies with 1194.21(a) through (l) is provided.