https://www.pewresearch.org/fact-tank/2016/04/07/who-relies-on-public-transit-in-the-u-s/ https://www.pewresearch.org/fact-tank/2016/04/07/who-relies-... "City

https://www.pewresearch.org/fact-tank/2016/04/07/who-relies-on-public-transit-in-the-u-s/ https://www.pewresearch.org/fact-tank/2016/04/07/who-relies-... "City dwellers are also more frequent users of mass transit. Some 21% of urban residents use public transit on a regular basis, compared with 6% of suburban residents and just 3% of rural residents." People are moving out of the cities, not suburbs, so this will have a very direct impact. > I'm also skeptical that the average apartment building is more energy efficient than suburban housing, since the incentive of the owner (who doesn't want to pay for energy-efficient upgrades and repairs) are not aligned with the renter (who pays the monthly utilities bill). The bulk of the emissions is generated by heating and cooling, and the former is the one with the most economies of scale. Around here, heating and hot water is usually paid for by the landlord in apartments (65% and 67% based on listings I just checked). That's not surprising: the way heating is provided is most commonly via hot water boilers, which don't make sense to provide on a per-unit basis. Anyway, it's just basic physics: apartment units have much less surface area to radiate or absorb heat compared to individual houses. Takes much less energy to keep an apartment with just one exposed wall warm or cool than a house with 4 exposed walls and a roof. Here's another source on this: http://www.frpo.org/wp-content/uploads/2015/04/2012-Apartment-Living-is-Green1.pdf http://www.frpo.org/wp-content/uploads/2015/04/2012-Apartmen... 3x less energy usage per resident for apartments vs single-occupancy detached homes. > Does a rural/suburban driver spending 30 minutes driving on a highway produce more pollution than an urban driver spending 30 minutes in congested variable speed streets? Absolutely yes. Energy usage is a function of speed, because the energy goes to overcoming air resistance. The scaling of velocity to energy usage is about v^3. Also, as the link I provided above shows, commutes are much longer - and public transit usage much less - for detached homes vs apartments. The only reason planes make sense is they can fly so high that air resistance is lower.