If folks won't leave their cars parked and walk somewhere just out of civic virtue, maybe they'll do it for money.

That's the logic behind Green Trips, a pilot program coming to Chattanooga via a federal grant aimed at improving air quality.

Green Trips will reward people for walking, biking, using transit or carpooling rather than driving alone each day to work or on errands. Prizes could be things such as discounts for restaurants, entertainment and retail, cash prizes or electronic gadgets.

"I think we all know we're going to keep vehicles around, but we'll have an alternative," said Melissa Taylor, director of long-range planning for the Chattanooga-Hamilton County Regional Planning Agency and its transportation planning division.

The executive board of the local transportation planning organization is expected to vote to approve the grant. It will take months to select a software vendor, connect with business partners and get Green Trips running.

Taylor hopes the program will "shift behavior."

"If you get them hooked ... and they see it's not that big a deal and doesn't take as much out of them as they thought, they'll keep doing it," she said.

Karen Rennich, RPA deputy director, said Green Trips will meld with other initiatives, such as the bike share program that's in the works.

In Knoxville's similar program, Smart Trips, members can win $50 and $100 gift cards, coordinator Alisa Ashouri said. Prizes in this year's annual "commuter challenge" among participating city businesses included Kindle e-book readers, iPod Nanos and a $1,500 vacation package.

The Knoxville program has been around since the 1990s and has about 1,500 members, Ashouri said. It also features a carpooling database and other efforts to coordinate ride-sharing or transit use, plus free downtown parking for carpoolers and free taxi rides home if a user's schedule falls apart.

Colleen Carboni travels on Tremont Street as she commutes to work on her bicycle.

Members log their trips and the Web-based program calculates the reductions in vehicle miles traveled and air quality emissions.

The members get prizes and discounts, but the program's real reward, Ashouri said, is the reduction in air emissions from vehicle trips not taken by some of Knoxville's 185,000 daily commuters.

"As a reference point, a half-pound of CO2 [carbon dioxide] emissions is enough to fill a large beach ball. The average commuter generates 100 of those beach balls every day in their commute," she said.

Multiply that by 185,000 and "you start to get a feeling for what we're talking about in terms of pollution," she said.

Ashouri concedes that the really dedicated users are concentrated in the city core, where transit and bike paths abound. But even if suburbanites have no choice but to drive to work, they participate by carpooling or by walking or using bikes or transit for lunches and errands.

Ashouri said area employers as far away as the Oak Ridge National Laboratory have been enthusiastic partners in Smart Trips. Businesses get tax breaks for participating, and the overall air quality improvement helps with business recruitment.

"It's a real win-win for any region to have a program like this," she said.

Dan Jacobson, vice president for properties and corporate services with BlueCross BlueShield of Tennessee, said a program such as Green Trips fits in with the insurer's focus on healthy workers and a healthy environment.

"There is a good-inside feeling about doing something that is green and contributing to being a more earth-friendly campus, a more earth-friendly individual," Jacobson said.

"We'd certainly be willing to look into the program and see how it fits into our overall corporation. It sounds like a great new way to promote good things, green things, and promote a little healthy competition."

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