Isn't there some requirement that a relatively nearby toll-free alternative route (not necessarily a highway) needs to be available for all vehicles?
Not providing a toll-free alternate route tells me that such a draconian restriction will probably result in lawsuits being filed by trucking companies/interest groups. Time will tell.
By AASHTO rule, a tolled US route must have a free alternate (excluding bridge tolls, of course). The other four existing US tolls all have a free alternate: the US 412 tollways in Oklahoma have US 64 (Cimarron) and Alt 412 (Cherokee), the US 278 tollway in SC has Business 278, and the US 51/I-90 tollway has IL 251.
What Delaware is doing here with US 301 is unprecedented in the entire US highway system's history. If the truck companies sued over this, I'm fairly sure they would win.
Should that happen; it wouldn't surprise me at all if DelDOT's reaction/remedy for such would be to redesignate US 301 in their state as DE 301 thereby bypassing that AASHTO rule. I'm surprised DelDOT didn't pursue such action when this tolled highway was planned.
But then it would end at a state line, which is a higher priority in AASHTO's list of things you aren't allowed to do with a US highway.
And at this point, they probably wouldn't allow moving US 301 back onto the old route, because that would be moving it to a lower-standard routing. I guess you can't win.
If I'm not mistaken, the toll-free alternative to the tolled US route per the AASHTO rule
need not necessarily be designated as US route number nor does it have to be the same grade of highway (expressway vs. arterial).
In reference to an example that I mentioned earlier: Circa 1971, when US 1 in the Boston area was rerouted onto a tolled harbor crossing (the Sumner/Callahan Tunnels) via the old MA C1; MA 99, which took over the old US 1 between Saugus & Everett and ran further south towards Charlestown, was born and became the routed toll-free river/harbor crossing (the I-93 extension to the Central Artery wouldn't happen until 1973).
Personally, I don't care which corridor (old or new) has the US 301 designation. The issue here is that there is no toll-free alternative route that
all vehicles can realistically use. In contrast, when the Delaware Turnpike (I-95) & the tolled portion of DE 1 were built (at different times);
neither of those tolled facilities obliterated an existing free corridor (a truck can still use US 40 to bypass I-95 or US 13 to bypass DE 1). I.e. for the new US 301; the notion of
"If you don't want a pay the toll, don't use the highway" can't apply here.
As stated earlier, had there been a partial, northbound exit/southbound entrance, with Middletown Warwick Rd. (former US 301) constructed just north of the border & south of the mainline gantry (granted, two of the four ramps at Exit 2 (DE 299) would be then redundant); such would've been compliant with the AASHTO rule/guideline/whatever.