You make little sense.
If people wanted smaller cars, they'd buy them. They've been available for decades.
What you are really doing is attempting to dictate the behavior of others. I can think of many regulations that would be far more beneficial to the environment than dictating what kind of car you can buy. But I hesitate to suggest them because people like you would immediately label me a fascist for advocating such policy.
And you'd be right. But no more so than you are already.