Minimum of 20-25, maximum of 70-75.
My hope is that within half a century years we'll look back at an age in which virtually ever adult was not only permitted to drive, but expected to do so as a matter of daily routine, with a mix of horror and bewilderment.
^^^^
Fun fact: Perhaps you don't know this from your urban liberal elitist bubble, but not everyone lives in a city or within walking distance of a public transit area. If you expect all these people to bike wherever they go you should be placed in an asylum.
So... if you think that we should be a slave to our current problems, and not try to make a better world, however slowly and incrementally that would take, why do you even care about politics?
Also, fun fact: I grew up in the suburbs. And Averroes lives upstate, in what I'm sure is not a transit-rich area.
And there are many others like him, who do not live in a major city but would like to break free from auto dependence all the same.
And the vast majority of transit riders are poors, so branding our position as "elitist" is, while good politics for a Republican I'm sure, frankly kind of insane.