Armed with new bikes and SmarTrip cards, two car-dependent men ditched their vehicles this month to pedal, walk or ride public transit for the next 30 days.

Matt Smith, 27, and Kyle Lewis, 26, beat out three other Arlington County residents to compete against each other as finalists in the county’s Car-Free Diet Skeptics Challenge in the hope of winning a year of free transit.

Meanwhile, more than 120 Arlington commercial property owners are competing to reduce their carbon footprints. And the County Board is considering an energy plan that would require 160 megawatts of solar panels, among other things, to drastically reduce greenhouse gas emissions by 2050.

This is part of Arlington’s long-term plan to be a green and sustainable community.

“This is something that has been part of the way Arlington has been functioning for many years,” said Chris Zimmerman (D), board chairman. “People recognize this is important and expect it of us.”

Arlington is not alone in this quest. Myriad projects are underway in the Washington region as local governments race to make cleaner, “greener” neighborhoods. Under financial and legislative constraints, jurisdictions are nevertheless upgrading public buildings, streets and sewers to include the most energy-efficient and environmentally friendly technology.

The changes aim to inspire residents and businesses to follow their lead, officials said.

A green roof will soon be installed on Alexandria’s City Hall. The roof, made of plants that soak up storm water and help insulate the building, will be visible from inside the planning office to encourage residents and developers to incorporate the idea into their designs. In return for taller buildings for its Tysons Corner headquarters, Mitre Corp. is including electric car filling stations into plans for the Fairfax County neighborhood. Montgomery County is developing programs to slow and rid storm water of pollutants before the water flows into regional waterways.

In the District, building owners are investing in renewable energy, such as solar and wind power, that equates to taking 102,000 cars off the road. Tunnels big enough to fit Metro trains are being built along the Anacostia River to handle harmful storm water. Rebate programs reward residents for installing solar panels or rain barrels.

“One of the reasons Washington is one of the greenest and most energy-efficient cities in the country is because we have everybody on board,” said Christophe A.G. Tulou, director of the District’s Department of the Environment. “We have a marketplace that demands these kinds of energy-efficient buildings we see going in. We have people in neighbor­hoods demanding to clean up rivers.”

The programs are paid for by a mix of federal, state and local taxes and grants. Alexandria City Hall’s green roof is being paid for with a federal grant. The $1 billion storm water tunnels being built along the Anacostia are funded through D.C. Water and Sewer Authority bills.

Legislative differences among the regional governments sometimes prove frustrating for lawmakers.

The District and Maryland counties have the authority to adopt laws for their jurisdictions. After public debate, the District adopted a 5-cent bag tax last year. The Montgomery County Council is considering a similar measure in the coming weeks.

Virginia is a Dillon Rule state, which means that a county or city that wants to adopt a new law must first be granted authority by the state General Assembly. Northern Virginia state legislators have requested the authority for a bag tax but were denied two years in a row by their peers.

Surveys conducted by the District after the tax was enacted show that 75 percent of those questioned have changed their ways and carry reusable bags, Tulou said. Retailers who thought the tax was a burden now report they are buying fewer bags and have less trash to clean outside of their establishments, he said.

“I hope we will look really bad if we don’t do this, because our neighboring jurisdictions have already done it,” said Elenor Hodges, Arlingtonians for a Clean Environment executive director.

But not all local officials share the same commitment to green and sustainable living.

“I’m totally focused on the nuts and bolts of local government — building schools, building parks, improving the quality of life — and not on some scientifically challenged political philosophy that . . . invests tactical resources in global warming concerns,” said Corey A. Stewart (R-At Large), chairman of the Prince William County Board of Supervisors. “It just is not, for me, the priority that should be the focus of local government.”

Prince William County does add energy efficiencies to county buildings and encourages carpooling and other cost-saving measures, he said.

Focusing on those financial benefits, and not the politics, is one way to move forward, said Scott Sklar, president of a marketing firm that promotes clean energy. Sklar’s business increased by 17 percent during the recession because more business owners realized how much money they could save by being energy efficient.

Sklar is a member of the group that drew up Arlington’s Community Energy Plan, which aims to reduce greenhouse gases by 70 percent in 40 years. The group was composed of representatives from utilities, local and federal government, businesses, schools and more. Fairfax County recently formed a similar group.

Despite all of the work local governments are doing with their own properties, public buildings and space only make up “a relatively small percentage of what could happen,” said Sharon Bulova (D), Fairfax County Board of Supervisors chairman. “If you are really trying to maximize energy efficiency and really trying to make a difference, you really need to reach beyond what government is doing.”

Bob Hoyt, director of Montgomery County’s Department of Environmental Protection, agreed. Hoyt’s office is tackling one of the most stringent storm water permits in the region, allowing minimal amounts of pollutants in the water.

“What we know is that the government just doesn’t have enough money or can’t regulate enough and shouldn’t regulate enough to clean up the water in the county,” he said. “What we need to do is reach out to the citizens and get them to partner with us in this effort so they care about the water in their neighborhoods, and they care about their local streams.”

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