The White House has touted its $3 billion "Cash for Clunkers" stimulus program as an extraordinary success, despite criticism that the program's actual environmental impact has been exaggerated. But while Clunkers has drawn the headlines, the administration has quietly sent millions more to state and local governments under a different program with similar goals: replacing old, diesel-powered buses with ones using cleaner technology.

It's not a high-profile program, and it wasn't even designed specifically to replace gas-guzzling vehicles. But the Transportation Department's Transit Investments for Greenhouse Gas and Energy Reduction (TIGGER) program has spent nearly half its $100 million grant budget to replace diesel buses with cleaner and more efficient hybrid-electric and fully electric models. Like Cash for Clunkers, these grants are intended to be dual-purposed: stimulate the economy and clean the environment.

The agency received more than $2 billion worth of proposals, a "robust" proportion of which were for the replacement of diesel buses with cleaner technology, Federal Transit Administration officials said. Of the projects that received TIGGER funding, 16 were for bus replacement in 13 different states. FTA suggested that the "readiness" factor played a large part in their choosing these projects. "Nothing is faster than buying a bus and putting it into service," an FTA official said.

Hybrid buses cost $150,000 to $180,000 more than their higher-polluting counterparts, but they offer better fuel economy and emit less carbon dioxide and smog-causing nitrogen oxides. They made up 3.8 percent of the national fleet as of January 2008, according to the American Public Transportation Association, up from 2 percent in 2006 and 0.2 percent in 2003. All told, the TIGGER grant program will put more than 185 new, lower-emissions buses on the road.

In addition to cleaner buses, proponents of the grant program pointed to the creation of green manufacturing jobs as a benefit that would result from building new hybrid coaches. The Illinois Department of Transportation, for example, estimates its project to replace 31 paratransit buses with hybrids will create 24 manufacturing jobs. The Regional Transportation Commission of Washoe County, which includes Reno, Nev., will be able to hire back 10 drivers laid off due to the recession.

Yet job creation isn't necessarily attributable to the TIGGER program alone. Eight of the participating transit agencies were planning to buy buses of some kind anyway -- the grant money just enabled them to upgrade to clean-tech models. Of the agencies that made new orders with the grant money, many of them said they were simply expediting existing multiyear plans to replace older diesel buses with cleaner technology.

The Connecticut Department of Transportation was the single largest recipient of money for bus replacement and got the second-largest grant overall. Encouraged by its existing hybrids, which require less maintenance and get roughly 20 percent better fuel economy than traditional buses, the department will use its $7 million to purchase two fuel cells and upgrade 20 diesel buses to hybrid-electric (at a total of $3.4 million).

"They do improve emissions somewhat," said Michael Sanders, transit administrator for ConnDOT's Bureau of Public Transportation. But he suggested that the agency wouldn't have invested in the pricier hybrids without the federal money. "They're not dollar-for-dollar cost-effective in hard cash," he added. "The difference is public relations, emissions reductions."

Henry Jacoby, co-director of the Joint Program on the Science and Policy of Global Change at MIT, was an outspoken critic of the Clunkers program. He calculated that each ton of carbon reduced cost the government more than $160 -- an expensive way to reduce emissions. "Cash for Clunkers was... being sold as a program to cut greenhouse gas emissions, but that's not what it was for," he added. "It was a program to help the auto industry." He was similarly skeptical of bus replacement as a cost-effective way to reduce emissions.

"The chief problem with the Cash for Clunkers program from [an] environmental standpoint was the small improvement for mileage that the law required," said Michael Gerrard, director of the Center for Climate Change Law at Columbia University, who was also a critic of the program. Cash for Clunkers only required an improvement of four miles per gallon in fuel efficiency in order for drivers to qualify for its subsidy.

Actual environmental improvements will vary substantially among the grant recipients depending on the specific buses ordered, the types of routes they run and the bus models they're replacing. CyRide in Ames, Iowa, which is replacing buses dating from the early- to mid-1980s, will see a steeper reduction in emissions than agencies using newer diesel buses, which already include many improvements to limit the release of pollutants. Still, switching to hybrids is a stronger minimum improvement. A similar requirement in Cash for Clunkers would have improved the program, Gerrard said.

Hybrid advocates acknowledge that hybrids are only a transitional technology. "Hybrid bus technology is terrific," said Bill Vincent, direct of the Bus Rapid Transit program at the nonprofit Breakthrough Technologies Institute. "But it's a transition technology. After all, hybrid buses still rely on petroleum."

Short of replacing all diesel buses with hybrids, transit agencies could maximize emissions reductions by replacing buses on routes that have a lot of stop-and-go, congested traffic, recommended Robb Barnitt, senior project engineer at the National Renewable Energy Laboratory, which is part of the Department of Energy. These types of routes are particularly conducive to hybrids, as they can operate in electric mode at low speeds.

"I think it's a technology that's only scratching the surface," he said. "It certainly grabbed a toehold in transit, and it will only continue."

More in Energy Go to section

February 09, 2010 | Energy and Envrionment Bulletin

Chu Happy To Let Data Speak For Itself

February 09, 2010 | Energy and Envrionment Bulletin

Snow Scrambles Senate's Calendar

February 09, 2010 | Energy and Envrionment Bulletin

Need-To-Know Memo, Feb. 9

February 09, 2010 | CongressDaily

Locke Proposes New 'One-Stop Shop' Climate Agency

February 05, 2010 | Energy and Envrionment Bulletin

Green Groups Boxed In On Nuclear Issue