Architecture is a slow business, and city planning even slower.
Automobiles are often conveniently tagged as the villains responsible for the ills of cities and the disappointments and futilities of city planning. But the destructive effect of automobiles are much less a cause than a symptom of our incompetence at city building.
I've often thought that if planners were botanists, zoologists, geologists, and people who know about the earth, we would have much more wisdom in such planning than we have when we leave it to the engineers.
Make big plans; aim high in hope and work, remembering that a noble, logical diagram once recorded will not die.
In city planning, there is no limit to be fixed.