I was thinking about the effects of autonomous cars esp. the fact that they can park themselves after the driver left the car (CES 2013 Audi A7 on youtube) If this technology becomes mainstream it would make sense for the city to forbid parking on the streets which usually takes up one left line and one right line. The cars could just drive themselves to an parking lot close by (1 miles radius) That way there would be more space on the streets and therefore less traffic. And for the people that still don't have this function in their cars in 30 years they would have to walk, but that would be a minority very quickly. Kinda the same with the Greenzones in citys where old cars are not allowed to enter the city because of the bad emissions. What are you guys thinking about that? May that even come sooner than 20-30 years? maybe 15years? This is a good example of a road that would benefit from that.