There are something like 8 billion people on the planet now, (don't know the exact number). Everyone of them wants a nice house and a car. Going by the "Rule of 72", however many autos and trucks are on the roads today, at 2% growth there will be twice as many in 32 years. This indicates that twice as many road miles will be needed, or something near that. In an anti-science environment such as we have today where some people believe the Earth is flat, I'm not confident we will be able to solve the high consequence problems facing the planet.