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NTL Section 508 Accessibility Guide to Digital Submissions

NTL Digital Submissions Accessibility Checklist

National Transportation Library Digital Submissions Accessibility Checklist


This checklist is based on guidance for Federal agencies developed by the Accessible Electronic Documents Community of Practice (AED COP) of the Federal CIO Council. 

See GSA's Create Accessible Documents  (  for additional help evaluating digital content for conformance to the Revised 508 Standards (

NTL requires these completed PROPERTIES in PDF documents submitted to ROSA P: 

  1. The PDF has a short, but descriptive file name OR the document number as the file name. Providing a document title allows the user to locate and identify the document. 
  2. PDF Document properties are filled out: a) Title b) Author c) Subject d)  Keywords. This information is machine readable metadata that speaks to the authenticity of the document. [Common errors include titles left as Template.]   In Adobe Acrobat Pro, open the File tab and select Properties.  Separate Keywords with a comma or semicolon.

                pdf properties

Accessible PDFs include the following characteristics:

  1. Searchable text. A document that has images of scanned text is not accessible because screen readers cannot read a picture of text. Users need to be able to select the text to be read with a screenreader or magnified. 
  2. Document Language identified. Specifying the document language in a PDF enables some screen readers to switch the current speech synthesizer to the appropriate language, allowing correct pronunciation of content in different languages. 
  3. Readable fonts. The fonts in an accessible PDF must contain enough information for Acrobat to correctly extract all of the characters to text. Acrobat extracts characters to Unicode when you read a PDF with a screen reader or the Read Out Loud tool, or when you save as text for a Braille embosser. This extraction fails if Acrobat cannot determine how to map the font to Unicode characters.
  4. Navigational aids. Bookmarks, headings, and a table of contents assist all users in navigating the document  Bookmarks are especially useful and can be created from document headings. These features can be accessed using the keyboard without relying on the mouse, and allow for multiple way for users to navigation content.

  5. Document Structure Tags and Proper Reading Order. To read a document’s text and present it in a way that makes sense to the user, a screen reader or other text-to-speech tool requires that the document be structured. Document structure tags in a PDF define the reading order and identify headings, paragraphs, sections, tables and other page elements. The tags structure also allows for documents to be resized and reflowed for viewing at larger sizes and on mobile devices.

  6. Headings are tagged with a heading tag. Heading tags match document headings and follow the visual outline. The tags follow the visual/logical order of the document

  7. Alternative Text Descriptions for Non-Text Elements. Images and figures cannot be understood by the user of a screen reader unless there is alternative text associated with that image. Alternative text for images can aid many users, including those with learning disabilities. When screen reads encounter alternate text, they can interpret the element and read its alternate text description aloud. 

  8. Use of color combinations that provides a sufficient degree of contrast and no reliance on color or sensory characteristics alone to convey meaning. Meaning of color or other sensory characteristics is duplicated in text. Text passes the Color Contrast Analyzer. 

  9. Lists are tagged correctly. Lists have a parent tag, and have one or more nested list item tags.

  10. Data tables. Tables are identified with a “Table” tag. Table header cells have a “TH” tag and data cells have a “TD” tag. 

  11. Tab order and reading order matches the visual/logical order of interactive elements. 
  12. Link names describe destination/purpose or describe context.

Best practices:

Images, charts, tables, figures: Assistive Technologies (including text-to-speech and speech-to-text-converters) rely on proper formatting to improve the accessibility of documents for persons with disabilities. Use text alternatives for non-text content when creating your documents to achieve a similar level of understanding that a visual user would experience. Tables should have a header. Wherever possible, add concise alternative text to images and provide a longer description in an adjacent paragraph.

Set high-contrast colors for accessibility: Go to Edit Preferences or use the shortcut Ctrl+K to use high-contrast colors, select document structure for tab order, and enable assistive technology support. Clicking OK will set your preferences.