Self-driven cars still consume energy. In fact, since you don't need to pay for labor, the percentage of the cost for the operation of a self-driving car repres

Self-driven cars still consume energy. In fact, since you don't need to pay for labor, the percentage of the cost for the operation of a self-driving car represented by energy is larger. So, if grid electricity is cheaper than gas, you still win in proportion to how much time the car spends moving around, driver or not. Regarding adding a tax for gas cars, well... even termoelectric plants are more efficient/cleaner than in-vehicle combustion engines[1]. Also, cities might decide that they prefer the pollution happening somewhere else for air quality purposes, even if it's all the same at the global warming level. Keep in mind that when we are talking about the "carless, on-demand, self-driving" future, we are probably not talking about 2017. Optimistically, we are talking about 2027. But keep in mind how many of the cars you see on the road now a days are models older than 2005 or even 1995... that's how long a new mass produced Tesla is going to be with us, at the least. [1] Of course, electricity storage and distribution adds costs in the other direction... so we'd need to calculate which has a lower environmental impact per Watt. My bet is still on huge power plants being cleaner than millions of power tiny power plants on wheels...