In the 1920's roads and bridges were ubiquitous. Every country had roads and/or bridges and the vast majority of truly great civilizations had both roads and bridges.
Somehow, and just in the USA, roads and bridges were responsible for the development of the automobile.
Can someone switch on their Obama Context Filter and walk us through how roads and bridges in the USA were responsible for the development of the automobile?
I think you are pointing to correlation not causality.
The same innovative and creative environment allowed both
the expansion of roads and bridges and the development of cars.
In general, regarding the use of govt authority/resources to rebuild jobs/infrastructure/economy
what I learned from a lecture and author on the biography of Jesse Jones,
was that in order to recover from the depression, Jones called together private investors to work WITH govt to get projects financed. the point was for the govt to assist the private sector until the economy and development could sustain on its own WITHOUT govt instead of relying on continued support. But that part never happened.
In Houston, because there was adequate private investment to bail out banks and do a lot of the work indpt of govt, then there was not as much reliance. But nationally because very few areas and states had the same private resources as Houston and Texas, then replicating the same process depended on the federal govt. So that is why it started and was not gradually phased out as originally planned, instead people remained dependent.
And we are still fighting to this day over too much reliance on govt programs that are not effective checked for abuse of resources or authority, from the public housing to schools and welfares. And the real culprit I see in killing state budgets and the economy are the prison contracts wasting millions if not billions on ineffective programs at taxpayers expense that could already pay for health care, housing and education for victims and the public affected by crime as restitution to society. If the only thing that pays is crime, then we are punishing law abiding citizens with more expenses and bankrupting the system.
The soluions will need to come from the states, organizing resources around communities and issues addressed locally, and not mandated by the federal govt. The overreliance has to stop and people have to start paying themselves and investing locally to solve problems.