Ryan Avent had a great post this weekend on the future of suburbs vis a vis their relationship with gas prices.   Some great poins all around about how our physical environment will change with expensive oil:

So, first of all, there’s this:

We will, in time, return to 1970s and 1960s levels of air passenger transportation. I do not expect technological advances to prevent this because the aircraft need liquid fuels – no electrically powered substitutes available. Boeing’s much ballyhooed 787 Dreamliner only boosts fuel efficiency 20%. Aircraft fuel efficiency would need to improve by multiples to compensate for Peak Oil and energy substitutes would have to be in the form of liquid fuels. Unless algae genetic engineering solves the problem we’ll do a lot more of our travel on the ground. Robert Rapier has explained better than I can the problems of algae biofuels.

I don’t know much about the potential alternative fuel or airline technologies, but I do know that last year’s oil price spike dealt a serious body blow to airlines. It seems to me that it will be much easier to handle rising oil prices on the ground than it will in the air. Intercity travel is very important, economically speaking, so this is a good reason, in addition to the environmental benefits, to invest in fast intercity rail. Highways are a very poor substitute for air travel.

In my mind, this is exactly right.  Even biofuels are questionable substitutes for air travel.  Heavier than air flight needs an energy source that’s extremely powerful when compared against the weight of the fuel.  The Air Force experimented with nuclear powered aircraft back in the ’60s, but couldn’t make it work.  There’s just no plausible alternative to hydrocarbons for air travel.

The implication, of course, is that a future with expensive oil would put a much larger emphasis on rail for intercity travel.  Airlines will still serve long haul and international routes, as even the fastest trains can’t compete on transcontinental and (obviously) intercontinental routes.

For cities, this is a tremendous long-term opportunity.  Airports are tremendous gateways for cities, but the nature of air travel and the space it requires for runways, terminals, hangars, safety zones, etc is extremely unfriendly to urbanism. Rail terminals, on the other hand, have a much better history of integrating well into the urban fabric and urban transportation systems.

Not that airports would be useless – to the contrary, this would be an opportunity to integrate rail and air travel.   In DC, a site between Crystal City and National Airport has potential to do just that.

Much of the remainder of the discussion centers on high gas prices forcing a return to urbanism in a large scale. Avent:

When urbanists like myself argue in favor of better policies, it is (generally) not with the belief that we all should or ever will live in very dense urban environments. Rather, I think that we should improve policy, and that the result will be slightly fewer living in low-density environments and slightly more people living in high-density environments. And it’s worth pointing out that “high-density” can mean many things — everything from Midtown Manhattan, to the walkable rowhouse neighborhoods in the District, to transit-oriented neighborhoods in places like Arlington where dense development around transit hubs rapidly gives way to detached but compact single-family homes. To the extent that any urbanist out there is arguing that everyone must live the condo and Whole Foods life, I’m ready to declare that they’re wrong.

I agree completely.  “Urban” densities can range anywhere from Manhattan to compact, single-family home areas interspersed with a few apartments, condos, and mixed use neighborhood retail areas. Likewise, ‘urban’ densities do not need to be in ‘urban’ locations.  Many people don’t want to live in the big city, but like walkable urbanism nonetheless.

What’s more important in my mind is to set the rules so that such densities (and the requisite pedestrian-friendly designs and land use patterns) are not just possible, but encouraged.  Avent notes this as well:

It seems pretty clear that government policy — via things like highway subsidies, mortgage-interest deductions and FHA lending, zoning rules, and so on — has strongly encouraged suburban development over the past half century. The market has therefore provided too much suburban style housing and too little urban housing.

It’s not just about understanding how we got here, we also have to change those rules so that urbanism is no longer illegal.  We need to adjust surface transportation policies to build more transit lines instead of freeways.  We need to make rental housing a more attractive option – or at least avoid stigmatizing renters or overly favoring homeowners.

All in all, rising gas prices will continue to provide a great way to frame how all of these issues are interconnected.  My gut tells me that people are understanding these realities far better now than they have in the past.