The data problem that holds back climate action and smart growth
For years, advocates of smart growth and New Urbanism have tried to get transportation departments to put more of their money into mass transit and into street and road networks that foster community life — rather than into mainly building and maintaining highways. Some progress has been made on that front, as the Obama administration has shifted federal policy toward a smart growth perspective.
But it’s now becoming clear that the transportation establishment suffers from another distinct problem: an inability to determine whether the transportation network is producing what today’s environmentally-oriented society is calling for.
Scientists have repeatedly said we must reduce the greenhouse gas emissions that cause global warming. Many of those emissions come from the more than 250 million cars and trucks hurtling along the nation’s highways. Yet the transportation establishment is unable to produce truly helpful calculations about how to reach the reduced emissions goal.
David Kooris, vice president of the Regional Plan Association (RPA) in greater New York, articulated that problem in New Haven Sept. 17 when he was the key speaker in a roundtable discussion of transportation and climate change, hosted by Yale University’s School of Forestry and Environmental Sciences.
“The transportation planning institution has been focused on cars and highways for so long that the tools that are available to them are not able to answer the questions that face them,” Kooris said. The transportation establishment is being asked to help reduce the negative impact of cars and trucks on the world’s climate, but in this era of sophisticated modeling, transportation agencies have fallen flat, he indicated.
Conventional transportation planning has focused on “speed, distance, and throughput,” Kooris pointed out. But speed, distance, and throughput (the number of vehicles accommodated) no longer tell us everything we need to know — if they ever did. Some of the chief things that need to be emphasized today, according to Kooris, are “access, proximity, and VMT [vehicle miles traveled].” The overall number of miles driven should be cut, to help the world avert hotter and more erratic weather.
To achieve a large enough VMT reduction, it’s necessary to know where vehicular trips are taking place, how long they are, and how much the trips shrink in response to various kinds of development patterns, various mass transit options, and other public policies and interventions.
Can this information be obtained now, in enough detail to apply it intelligently at the local and regional level? The answer is no, according to Kooris.
“The problem is data availability,” in Kooris’s view. “It’s difficult to get data that is reliable and that answers the questions we are now asking.”
Some things do seem to be known, of course. In Connecticut, for example, it's been calculated that 92 percent of carbon emissions result from the combustion of fossil fuels. Approximately 40 percent of that combustion comes from the transportation sector. Greenhouse gas emissions per year in Connecticut, which have been hovering around 44 million tons in the past few years, need to be brought down enormously — to less than 10 million tons. That’s one of the reasons why cutting VMT is crucial.
If a reduction of 12 percent could be achieved through smart growth strategies such as building more compactly, at densities and in locations that support transit, walking, and bicycling, that “would be a significant part of the solution,” according to Kooris. “VMT is a big challenge. It is central to attack VMT.”
Information that’s helpful in some respects can be gleaned from the National Personal Transportation Survey and from the US Census transportation planning package. Massachusetts and Illinois collect odometer readings, which Kooris describes as “probably the most accurate” statistics available. In most places, however, such figures are not collected or made available.
Meanwhile, housing in outlying locations has made driving a necessity. Some of that housing is the direct result of government action. On Long Island in New York, affordable housing tends to be built “where the county owns land,” Kooris points out. “It’s in the middle of nowhere.”
RPA is working on two models that predict VMT — “by where people live and where people work,” says Amanda Kennedy, a planner in RPA’s Stamford, Connecticut, office. Presumably those models will be useful for educating governments, planners, and the public about policies that result in less driving.
Mike Krusee, a former Texas state legislator who served on a national commission examining how to reform the federal transportation apparatus, has said that with today’s technology, it would be possible in about a decade to equip the majority of American vehicles with devices that record trip distances. That information could be used to determine how much fuel tax an individual motorist should be charged. That, in turn, might produce remedy for the transportation system’s increasingly inadequate revenue situation.
Such detailed VMT figures also could conceivably help planners understand — much more precisely than they now do— how the various instruments wielded by government, such as policies favoring compact and transit-oriented development, can reduce greenhouse gas emissions.
We’re currently a long way from being able to do the fine-grained calculations that Kooris believes are needed. One reason for hope is that there is growing talk about “performance-based” transportation funding.
“If transportation funding becomes increasingly dependent on performance,” as is possible in the next federal transportation bill, greater attention may well be paid to outcomes such as congestion mitigation and emission reduction,” according to Kooris. That would probably encourage governments to make more connections between transportation decisions and land-use planning. Planning could take a more integrated approach.
For now, though, those who want to tackle global warming by reducing the need to drive and fostering compact communities are hindered by the transportation establishment’s slow pace in devising the tools America needs.