It's increasingly clear that land use planners are not quite sure what to do about climate change.

For the third consecutive year, the subject of climate change dominated the annual conference of the American Planning Association, California Chapter. What was evident during this year's event, which concluded September 16 in Squaw Valley, was that the issues are extraordinarily complex, and the available tools are not ideal. Planners, as well as engineers and attorneys, acknowledge they are "just making it up as they go." No one appears to feel comfortable about it.

The generally accepted premise is that certain land use patterns and urban development forms result in less emission of climate-altering greenhouse gases (GHG) than other land use patterns and urban development forms. Because most of the GHG reductions derive from decreased use of automobiles, the emphasis is on compact, walking- and cycling-friendly, mixed-use development near transit.

So far, so good. But …

• CEQA is not climate friendly. In our state, the California Environmental Quality Act lords over every land use plan, public works project and real estate development. And, as Bill Fulton wrote last week, CEQA reviews often cite increased traffic as a negative impact. How do we typically mitigate for that impact? Build more and wider roads – so that it's easier for people to drive!

• LOS is the wrong measurement. Level of service is a traffic congestion measuring stick. At LOS A or B, traffic moves freely. At LOS E or F, bottlenecks and slowdowns are common. Many jurisdictions have adopted LOS C or D as their standard. The way to achieve a high LOS is by building lots of wide streets and roads that move cars quickly – so that it is easier for people to drive! "LOS is going to work against your walkable area," City of Modesto planner Cindy van Empel summed up during one panel presentation.

• "Our transportation models suck." So said the always-candid Jennifer Hernandez, an attorney with Holland & Knight. Indeed, I heard over and over at this year's conference that the Institute of Transportation Engineers' trip generation handbook incorrectly predicts the number and length of trips produced by a California development, and that the ITE handbook is worthless for forecasting GHG emissions. Ron Milam, of Fehr & Peers, and Jeffrey Tumlin, of Nelson/Nygaard, talked up the need for transportation models to take into account factors such as building density, urban design, diversity of uses, proximity to transit, transportation demand management systems, and demographics. Research is starting to show that mixed-use, transit-oriented infill development produces one-third fewer vehicles miles traveled (VMT) than typical greenfield development, according to Milam.

• It's not that simple. The overarching objective seems to be reducing VMT. But Shari Libicki, a Stanford professor and principal in consulting firm Environ, pointed out that not all VMT is the same. A car with a cold engine making a low-speed, two-mile trip may generate as much carbon dioxide as a car with a warm engine traveling 10 miles at freeway speed, according to Libicki. Considering that people are always going to drive some, which trip should land use planners try to encourage?

One thing that is certain is that the field is evolving. Maybe we will achieve total enlightenment during next year's APA California conference in Carlsbad. Or maybe we'll just be one step closer.
– Paul Shigley