I agree that the economy needs a boost, and that infrastructure is important, but the internal combustion engine is a dead end. We shouldn't pour more good money after bad. Global warming threatens our economy, our ability to feed ourselves, and many of the species that make up our world. Roads are the major factor allowing wildlife to be killed, habitat to be destroyed, logging, mining, and other unsustainable environmental destruction.
Roads cover precious farmland and desirable living space.
The construction of mass transit facilities makes far more efficient use of resources than does road construction. One rail line can carry the equivalent of several highway lanes. Transit construction and operation also creates far more jobs, and higher quality jobs, than does road construction and operation. Motor vehicles burn up billions of gallons of oil that could be put to far more beneficial use. There will be considerable pressure to rip out most of the roads we are building and maintaining now, since the traffic won't be great enough to justify maintaining them.