As an architectural intern, I have to deal with issues of accessibility and universal design all the time. That means to be concerned not only with the minimum dimensions required by the building code (yeah, how'd you guys like them 1:12 ramps? pff!) but to think about the wider issues of common entrances/ease of location/legibility of signage etc. It's pretty hard and frustrating sometimes, but I try to see the ADA regulations as opportunities for innovative design. One pretty wicked example of this is the stair/ramp designed by Arthur Erikson in Robson Square, Vancouver: http://www.greatbuildings.com/cgi-bin/gbi.cgi/Robson_Square.html/cid_1820069.html

And yeah, I know this isn't an example of fail... I'll tell you all about the Montreal Metro system another time, to make up for it ;)