Boarnet argues that one branch of the Interstate Highway System should have been reserved entirely for intercity roads. These would be highways running through remote areas with cheap land and sparse populations, so it would make sense to prioritize traffic flow and vehicle capacity. Paying for this branch with a pooled fuel tax would also make sense, because the benefits of low-cost transport and trade redound on everyone.
The other branch of the system would be made up of intracity roads, those running within the city limits. Given the high cost of land and density of population in cities, creating sufficient road capacity and swift vehicle flow would become a pipe dream, so the wiser aim would be transport balance. The logical way to finance these roads, given the great demand for space on them, would be with direct user fees — ideally priced to reduce congestion.
It’s difficult to envision what this two-part system would look like, though we can get a good idea of how the first half would function if we keep the the auxiliary loops and abandon any through-city trunks or spurs.
In that case, I think we’d see a very different world, one where interstates aren’t relied upon for commuting. That would have changed the city-suburb dynamic drastically and perhaps given rail a fighting chance.