Originally Posted by mbstone
The "full faith and credit" clause of the U.S. Constitution means that a disabled-person placard or license tag from one U.S. State or territory is valid nationwide, just as is your driver's license.
Right, with the only exception being New York City. Before anybody says it, some jurisdictions, like Washington DC have limitations on use of out-of-state placards but they are still valid. (In DC you can't park at a parking meter for free or for twice the meter's time, like those with DC Placards can. You can park in designated spaces with out of state placards though.)