My hope is that if someone sits alone in their big SUV stuck in traffic, pedestrians, cyclists and others will look at that person disparagingly. Like how people look at dog owners not picking up their dogs feces, cigarette smokers or how they look at obese people buying ice cream... Or how hypochondriacs who go to the doctor when they don't need to are shamed in countries with socialized health care.
Maybe it is not nice to use shame as a weapon, but it is a powerful one. We have about ten years to completely change how our societies work before it is to late. All options should be on the table.