The inexorable downward decline of the urban density gradient has been fueled by cheap gas and massive highway spending, coupled with gains in farming efficiency that freed up Burnsville, Eagan, Farmington, etc. from their farmland roles. There had never in the history of humanity been a period like the 1990s in the Twin Cities where gas was so cheap, highways so plentiful, and food so cheap.

Start turning these trends around and perhaps the denisty gradient does begin to steepen: food and farmland with higher values, gasoline more expensive, highway projects questioned due to costs and questionable long-term need. Homeowners at the periphery of the Twin Cities and many American cities are now finding out that the homesite they bought into was a bad deal due to commuting cost. People are not stepping tin to take their place, but it can't easily be reconverted to farmland either.

The people in the Twin Cities are fortunate to have one decent light rail line in place and will soon have another connecting the two downtowns. These are good things.

I don't understand why you hate downtowns. To be on Nicollet Mall at noon when the farmers' market is taking place and all those office workers are buying fresh veggies is a sight to behold, and it reminds us why the standard urban model performed so well in the first place.

I'm a retired North Dakota farmer. There is nothing downtown I want. I'm not interested in the bars, the concerts, the trendy shops, the traffic, the noise, the sensory overload. The Walker Art Center is an ugly, ugly building with the face of an angry robot. The inside is just as ugly as the outside and screams anomie.

At my son's house in Burnsville I'm a block from Red Oak Park and two blocks from Highland Park, places I take my granddaughter twice a day. There's a commons area within my son's immediate community that has large grassy areas and paved walkways that are not next to car traffic. I can watch Coopers Hawks nesting and yesterday a doe and fawn ran across the street in front of me. I'm a 15 minute walk from Mexican and Thai restaurants, two Russian grocery stores, and a drug store, as well as several other services. I'm a 15 minute bike ride from two Cubs and one Aldi's supermarkets and a Target and hundreds of other stores, restaurants and services. For a city, it's pretty quiet, except for airplanes going up and down the Cedar Ave. glide path. When I look out my son's sunroom windows, all I see is trees, a slough and no buildings. The neighbors are friendly and know each other.

Why would I want to go downtown, where everything, except Loring Park, is concrete? When my wife was going to graduate school at the University of Minnesota, we lived on the West Bank in the Riverside apartment tower complex. It was all concrete. You can bring vegetables to the Nicollet Mall, but it's still all concrete.

These blogs tend to focus on metro areas. What about the rest of us? On weekends I'm in Mankato, where my wife is a professor. This is a community of 45,000 and has city bus service. But what about the rural area surrounding Mankato and its small towns? There's an aging population. It's going to need the American equivalent of the Turkish "dolmus" bus system in the future, but something like that never gets discussed. Our permanent home is in northern Minnesota near the Canadian border. Bears outnumber humans. I'm 14 miles from the nearest village; 45 miles from the nearest city; 110 miles from the nearest SMSA; 250 miles from the metro area. If you don't have a car, your mobility is seriously curtailed. There is no public transport. Winter lasts six months; continuous snow cover goes from Halloween until after Easter. The temps Portland has in winter, we can get in July.

If one thinks that changing our transportation system will be expensive, changing housing practices for Americans will be an order of magnitude more expensive and difficult. That's the point I was trying to make. There are no fill-in areas in the Twin Cities metro area inside the outer ring suburbs, unless one is talking of pouring a lot of concrete to build high rise condos. And then these people will be commuting from the core city out to their jobs in the suburbs, unless you want to move the jobs and schools and services into the core cities too. That's a lot of real estate to change.

Let's think about how to move people efficiently using linear transport to meet an isotropic flow. That's a difficult and expensive enough problem without also trying to move real estate.