I've argued several times for tolling I-35 through Austin to relieve congestion, lowering the tolls on SH 130 if necessary. I'd never bothered to check whether the feds would permit it, though.
Apparently, they might. I glean this from a Federal Highway Administration press release disclosing that it has rejected Pennsylvania's application to toll parts of I-80. According to the FHA official, “Tolling interstates is a viable option for many states to fund highway improvements or to improve performance conditions.” "Tolling . . . to Improve performance conditions" sounds like congestion pricing to me. (Pennsylvania didn't satisfy the federal standard, but a jurisdiction with a reasonable pricing scheme presumably could.)
(h/t Ben Wear)
The internet is cool.
