I-97 in Maryland for being the shortest 2di.
Which doesn't as much violate technical Interstate standards as roadgeek sensibilities. What's interesting about I-97 is that its original configuration also included all of unsigned I-595 deployed over US 50 between I-495 and the I-97 junction; the route was meant to be a sideways "V" shaped route with the intent of connecting Annapolis and its Naval facilities to both Washington and Baltimore. Later, the southern (I-595) portion was to be the original iteration of I-68 before the hidden I-595 designation was applied. If that were to be signed as per its original format, I'm sure there would be a bit fewer objections about I-97's overall length -- but at the expense of new ones about its shape! Nevertheless,
all of I-97, current
and original, meets Interstate construction standards.