Thirty years after the Americans with Disabilities Act became law, most of the nation’s public school districts remain inaccessible to students with disabilities, government investigators say. A Government Accountability Office report out late last week finds that in 63 percent of public school districts, at least a quarter of facilities aren’t physically accessible to those with disabilities. Problems at the schools included steep ramps, inaccessible playgrounds and restrooms and door handles that are difficult to use, among other issues.