Basically, there are no tactile differences between the bills, and U.S. Court of Appeals for the District of Columbia Circuit has ruled that this is in violation of the law.

Among other things, they said that the government did not shot that fixing this would be an undue burden.

When you consider the stuff that they’ve done lately, putting a bit of texture on the bills has got to be cheaper than the holographic inks, etc. that they are using/

The case is American Council of the Blind v. Paulson.