I can't see why people in cities can't have have or make use of s public transport system more efficiently. Go for a drive in Sydney at peak hour and take notice of how many cars actually have more than one person in them. That's the real problem. Stop building 7 bedroom McMansions on blocks 40km away from where the work site is. Higher density housing would eliminate a huge amount of wasted energy. And truth be known, that is the answer to city smog which is the sign of wasted fossil fuels.