Addressing Structural Barriers
When you're taking in a play, movie, or musical concert, visiting a museum or any type of public building, it's good to know how the Americans with Disabilities Act (ADA) works to ensure equal access for all individuals. Below is an excerpt from the ADA regarding public accommodations — stores, restaurants, theaters, hotels, museums, stadiums, etc.
Basically, all newly constructed public buildings, including renovations and additions, must provide equal access to all consumers. Public buildings existing before the enactment of the ADA must remove architectural and communicational barriers.
Keep in mind that some businesses comply in better ways than others. For example, not every place has an automatic entrance door to the building, but does provide personnel to open it. (It would be nice to not have to wait for someone to open it, but the building is still in compliance as long as the doorway is wide enough for a wheelchair to pass through it.) See also, Accessible Stadiums for a detailed example of compliance.
Click here for the 2010 ADA Standards for Accessible Design.
Another source of information on the ADA is the U.S. Access Board, also known as the Architectural and Transportation Barriers Compliance Board.  This is a federal agency that promotes equality for people with disabilties through leadership in accessible design and the development of accessibility guidelines and standards.