A key challenge faced by many K-12 students with disabilities is obtaining academic print materials in an alternate format. Students who are unable to read standard print (for instance, students with blindness, low vision, or learning disabilities) require their materials in an alternate format, such as Braille, large print, or audio. Increasingly, the medium of choice is electronic text, since students with print disabilities can read, navigate, and search the text with off-the-shelf information technology, perhaps in combination with assistive technologies such as synthesized speech.
Many states have passed accessible textbook laws. Although they vary in their approach, they all attempt to serve the purpose of getting accessible learning materials to students with disabilities in a timely manner. Kentucky has been a leader in accessible textbook legislation at both the K-12 and postsecondary levels. For more information about Kentucky's postsecondary legislation, consult the AccessIT Knowledge Base article The Kentucky Postsecondary Textbook Accessibility Act: A Promising Practice in Textbook Accessibility Legislation .
In the K-12 arena, Kentucky's Senate Bill 243  (later �156.476, available as a Microsoft® Word document) is a promising practice because it ties accessibility to the textbook adoption process. The law requires that any publisher of a textbook or program adopted for use in the K-12 public schools provide those same materials in an accessible electronic format. It gives preferential procurement status to textbook and instructional materials from publishers who do so.
SB 243 is also noteworthy in that it established a state repository in order to coordinate and facilitate the timely delivery of accessible materials. The Kentucky Accessible Materials Consortium  reviews all materials for accessibility, maintains a database of accessible materials, and provides training and technical assistance to publishers and schools in accessible file preparation, accessible technology, and use of accessible content.
Also, the SB 243 regulations  (704 KAR 3:455) were the first to clearly document a hierarchy of file formats based on their inherent accessibility. Previously, laws had documented general requirements for accessibility of file formats, such as the requirement that file formats preserve documents' "structural integrity." However, little or no guidance has typically been provided as to which file formats best met this requirement. The SB 243 regulations provide extensive guidance about the accessibility of file formats by establishing three levels of compliance: Level 1 ("full compliance," which includes XML, XHTML, or HTML format), Level 2 ("provisional compliance," which includes RTF or Microsoft Word), and Level 3 ("marginal compliance," which includes "unlocked PDF").
Also, both Kentucky's K-12 and postsecondary accessible textbook laws define print disabilities broadly, allowing for the provision of alternative versions of materials to a wide range of students. Many states' accessible textbook laws focus specifically on a narrow range of students, such as students with visual disabilities. In some cases this is extended to include students with learning disabilities. However, the Kentucky laws extend the definition further still, "including but not limited to students who are blind, are visually impaired, or have a specific learning disability . . . or other disability affecting reading."
For additional information, consult the AccessIT Knowledge Base article Which states have accessible textbook laws and what do they say about file formats? 
-  The Kentucky Postsecondary Textbook Accessibility Act: A Promising Practice in Textbook Accessibility Legislation
-  Senate Bill 243
-  Kentucky Accessible Materials Consortium
-  SB 243 regulations
-  Which states have accessible textbook laws and what do they say about file formats?