Why does the Federal Government have to be involved in it at all? If a highway is beneficial for trade to both states as most highways are, there is no reason the states could not get together and arrange a joint construction project.
Of course, we need federal masterminds.
The Feds need to be reinvented, sans the 99% fluff.
You need national, state, and local roads. In spite of what you say, roads that cross jurisdictions almost always change in quality. Not just interstates or US highways but states roads also. Or when a city street becomes a county road. In Texas where each County Commissioner controls the road/bridge money in his precinct, the roads can change drastically at the precinct line.
If you are talking about Interstates and US Highways, the federal money available covers only maintanance and essentially nothing for new roads.
When the Interstate system was designed and built it was primarily an east west system but because of population shifts and NAFTA, we need more/better north south roads.
Nobody wants to talk about it but all over the world we see nations integrating their roads. When the subject of the US and Mexico integrating roads comes up, the kooks start howling about the North American Union.
I don't mean to be cynical but this road issue is like many, many other issues. The GOP's unspoken agenda is to de-plumb and de-wire the federal government before the brown people take over. Rolling back the 20th century.