> Other locations have "Backup" highways to lighten the load or otherwise take up the slack if the main road closes. Not so here.
Well... not really. Taking the 95 corridor in the Northeast as an example, the only places with alternative highways are 95/295 between DC and Baltimore, 295/NJT in lower New Jersey, and Merritt Parkway/95 in Connecticut to New Haven. In all of the other segments, 95 doesn't have a close-ish parallel highway to take off traffic.
And when you dig deeper into traffic statistics, the traffic tends to be heavy on both segments at the same time. That is, there are two highways there because the traffic needs require there to be two highways; the second highway isn't just "merely" a there-for-when-the-first-one-is-full kind of highway. And induced demand basically says that it's impossible to have that kind of highway setup.
Well... not really. Taking the 95 corridor in the Northeast as an example, the only places with alternative highways are 95/295 between DC and Baltimore, 295/NJT in lower New Jersey, and Merritt Parkway/95 in Connecticut to New Haven. In all of the other segments, 95 doesn't have a close-ish parallel highway to take off traffic.
And when you dig deeper into traffic statistics, the traffic tends to be heavy on both segments at the same time. That is, there are two highways there because the traffic needs require there to be two highways; the second highway isn't just "merely" a there-for-when-the-first-one-is-full kind of highway. And induced demand basically says that it's impossible to have that kind of highway setup.