I would estimate that it started with Brown v. Board of Education in the mid 1950s. As racial integration started we saw "White Flight" from city centers. Natur

I would estimate that it started with Brown v. Board of Education in the mid 1950s. As racial integration started we saw "White Flight" from city centers. Naturally, those people exiting the cities wanted a way to enter the cities for jobs, education, entertainment, etc... So then we saw the construction of Urban Freeways in the 60s and 70s. Before then, cars were unaffordable for almost everyone. It was kind of like owning an airplane nowadays. It was doable, but most didn't bother unless they really needed one since there were more affordable alternatives and you could walk everywhere you needed to go anyways. Since then, things have only gotten worse as we slowly make cars the only viable method of transportation through land use requirements and neglected infrastructure.