We have as much road capacity today as we will ever need.In my efforts to get Portland, Oregon's Peak Oil Task Force, [which identifies problems and solutions related to dwindling oil supplies], into Vancouver, I've run up against hurdles from the business community as well as from the climate community. So I've been really interested in saying, "Okay, how do we collectively start to get past our differences and focus on the commonalities?"If we are investing in efforts on climate strategies that do nothing to address oil dependence, then we are really missing an opportunity to be strategic about how we use time and money. Energy security is important; emissions and climate change are important; but let's prioritize those strategies that address both. In terms of what we do immediately, we should be focusing on strategies that reduce both emissions and oil dependence.When you start to look at peak oil and climate change, it all comes down to how quickly they happen. Technology plays a big role, but it doesn't get us all the way. Part of what I am trying to do is to show the scale issues and the speed issues. It's the idea that the energy transition isn't just about technology; it isn't just about cultural transformation; it isn't just about the economy or anything else. It's about all of these things together, and how quickly they change.On the transportation side, I look at our history of investing in infrastructure. We spent (and are spending) billions and billions of dollars creating the interstate-highway system, and increasing the size of our airports and ports. There is this default assumption that we are going to keep growing those things bigger and bigger, off into whatever kind of future we imagine. I protest that sort of assumption-that everything we are doing is about getting bigger and bigger.Ultimately, sustainability means coming to terms with natural biophysical limits. So we have to get past this idea of planning around extrapolation of past trends. That the future may be different than the past is the first thing that we need to come to terms with. This is where the idea of peak roads comes in: If we can say to ourselves, "We have as much road capacity today as we will ever need," then we can start to ask what that means in terms of how we should actually start designing our cities. This shouldn't be thought of as a default "anti-roads" statement. But our numerical models show that we simply may not have enough fuel (and biofuel, and electric cars) to use more road capacity than what we have today.If we can start to grapple with the fact that we can actually get better instead of getting bigger, then we have started on the path towards sustainability. And I think until we can really wrap our heads around that we are fighting an uphill battle.