The PREL website has been designed to be highly accessible to persons visiting our site through the use of assistive technologies. Visitors who need to make use of these features may include:

  • People with visual impairments who use text-to-speech converters (programs which convert web pages directly to text)
  • People with hearing impairments who may need phonetic equivalents for audio materials
  • People with impaired mobility who have difficulty using a conventional mouse or keyboard.
  • The following provides information for visitors to help make the most of these accessibility features.

Alt Tags

Images are provided with text equivalents which describe the content of the image. Images without visual content (e.g., an image which supports page layout) are provided with zero-length text equivalents.

Cascading Style Sheets

This website is organized so that it may be easily read without style sheets. When each page is rendered without associated style sheets it remains easy to read.


Data tables throughout the website identify row and column headers to identify content in each table.


All content included in this website can be clearly read on monitors without color.

Acrobat Documents

This site contains content in Adobe Acrobat format, also known as “Portable Document Format” or PDF. There is currently no available direct text-to-speech converter for Acrobat documents, as Adobe is currently developing this software. However, this site does provide a link to a text-only version of each Acrobat document. The accessible link is always adjacent to the link which references the original PDF document. The text-only version is provided by executing a service on the Adobe website. This service then retrieves the document from the PREL website, converts it to HTML and displays the result.

For persons who are not using a speech-to-text converter, the Acrobat reader may be downloaded from the Adobe website at