Many states have enacted the legislation for ABLE accounts including NY and CT and the federal legislation is in place too. However, as of 4-16 no state has the account operational so you can't open one.
In addition, Congress changed the rule in 12-15 so now you do not have to open an ABLE account in your own state..you can use any state. As a result, some states may not offer them or might create joint accounts with other states.
In the meantime, most people will use a pooled trust or special needs trust.