This can extend to Braille signage, wheelchair ramps, audio signals at pedestrian crossings, walkway contours, and so on.
In computing, this often includes high contrast fonts, modified keyboard actions, larger fonts, text-to-speech programs, alternative input device support, and the like.
On the World Wide Web, the W3C has produced specific guidelines for accessibility. The Cascading Style Sheets system has been devised with this in mind, since it gives the reader full control over the appearance of the page.
Various countries have legislation requiring accessibility: