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How To Cut Transportation Emissions In Half

If the United States really and truly wants to curb its oil use and lower emissions from the transportation sector, then, sorry to say, but cranking up fuel-economy standards for cars and light trucks isn't going to be nearly enough. That's according to a new report from Cambridge Systematics, a consulting firm:

The United States can cut greenhouse gas emissions from transportation in half by 2050 with strategies ranging from cutting speed limits to imposing road pricing, according to a report released today by federal agencies and environmental and industry groups.

Examining about 50 transportation strategies, the report found transportation emissions could be reduced 24 percent by 2050 by acting to change travel behavior and land-use patterns. The emissions reduction hit 47 percent by adding road pricing techniques, ranging from pay-as-you-go insurance to charging Americans for every mile driven.

The report found environmental gains from advances in fuel efficiency would be mostly undermined by increased travel and population, making it important to address the efficiency of the transportation sector by investing in public transit, land-use planning and other low-carbon alternatives.

Here's the full report, and the raw numbers are eye-catching. If all we do is rely on those beefed-up CAFE standards recently put forward by the Obama administration, then, by 2020, U.S. transportation emissions will still be 4 percent higher than 2005 levels, because advances in fuel technology and efficiency will get still swamped by the growth in population and vehicle-miles traveled. Efficient cars can only achieve so much if more people are driving them further and further. And, given that transportation contributes 28 percent of U.S. carbon emissions, any increase will make it awfully tricky to meet the targets in the House climate bill.

So actually cutting overall vehicle emissions will require a considerably more expansive effort. The list of policies includes lowering speed limits, ending subsidies for parking, setting up congestion tolls, bolstering public transit, encouraging urban density, promoting pay-as-you-drive insurance, shifting freight over to rail… pretty much every obvious thing you can think of. The list is endless. But the upshot, according to the study, is that all these moves add up to very large reductions in pollution and oil use.

--Bradford Plumer