I don't make this stuff up:
" Today there are approximately 6.8 billion people in the world, and within our lifetime, that number's going to grow to about nine billion. And at that population level, our planet will be dealing with the limits of growth. And with that growth comes some severe practical problems, one of which is our transportation system simply won't be able to deal with it.
When we look at the population growth in terms of cars, it becomes even clearer. Today there are about 800 million cars on the road worldwide. But with more people and greater prosperity around the world, that number's going to grow to between two and four billion cars by mid century"
Uhh, well Bill, maybe that is not such a good idea even with magic non emission electric unicorn Tesla cars, http://www.ted.com/talks/bill_ford_a_future_beyond_traffic_gridlock/transcript