DETROIT — When the Rev. Jim Ball and his wife began their cross-country trip, they weren't sure how other drivers would react to the "What Would Jesus Drive?" signs on the doors of their Toyota Prius.
"We thought we might get a few interesting gestures along the way," Ball says.
That's a polite way of saying they knew fingers would be pointed at them, but which ones?
In Arkansas recently, a couple of men on motorcycles rode alongside their car. One of them pointed to the sign, then gestured to his own motorcycle, to indicate Jesus would be an easy rider, too.
"I couldn't quite argue with that," Ball says with a laugh. "They're pretty fuel-efficient. I gave him the OK sign."
Ball, executive director of the Evangelical Environmental Network, and his wife, Kara, are spending part of the summer on the road to promote the "What Would Jesus Drive?" campaign.
The couple started their journey on May 29 in Austin, Texas, and plan to end it in Washington, D.C., on July 7. Along the way, they're making frequent stops to meet with religious and political leaders, preach and do interviews on Christian radio.
Their swing through the Bible Belt is another step in a campaign that started in November, when Ball and his national coalition of evangelical Christians came to Detroit to kick off "What Would Jesus Drive?" and to join a delegation of interfaith religious leaders pushing for cleaner cars.
The publicity from that visit led to a high-octane national debate on whether there are moral aspects to fuel-efficiency.
Critics dismiss "What Would Jesus Drive?" as a cleverly named crusade that obscures the fact cleaner cars are hardly a pressing moral concern. If Jesus were around today, they argue, he'd have more to worry about than transportation options.
Supporters of the movement say it relates to Jesus' most basic teaching: Love your neighbor. Taking care of the planet, their thinking goes, is akin to taking care of all God's creatures.
To drive the point home, Jim and Kara Ball are traveling in their 2003 Prius (PREE-us), a hybrid car that combines a gas engine with an electric motor. They bought the vehicle in October for about $20,500.
The journey is like many other religious revivals that have swept through the Bible Belt.
It also has the trappings of a classic summer road trip: snack food, long hours, which tourist sites to see.
Calling by cell phone just outside of Little Rock, Ark., Jim Ball, who's from Maryland, describes the couple's routine.
While Ball talks, his wife does the driving. At the moment, she's doing 64 mph in the right lane of a freeway where the speed limit is 70 mph. As usual, the other cars are passing them.
The weather's been good so far. So has the behavior of the drivers they meet. The couple haven't encountered the kind of road rage that would force them to contemplate another potentially intriguing topic — how would Jesus drive? Still, Ball is happy to contemplate the question.
"How we treat others in our vehicle, in terms of our driving, is certainly part of being a Christian," he says. "Aggressive types of driving, I don't think the Lord would want us to be doing that, things that put people in harm's way. We really haven't encountered too much of that yet."
The long hours on the road are usually spent doing phone interviews or navigating. Every once in a while, there's time for sightseeing. In Austin, they saw North America's largest urban bat colony, which lives under a bridge over the Colorado River.
As for the condition of the Prius, Ball says it's doing great. He stresses he's not out to promote a specific automobile and says he makes sure to tell people about other hybrid cars, current and upcoming.
Still, the Prius is a star of the trip. Wherever the Balls go, people want to look under the hood and examine the battery pack.
Ball says newcomers are surprised when the internal combustion engine goes off and the car, still running, turns quiet. They ask a lot of questions about the dashboard readout that tells where the energy is coming from at any given moment.
"We're giving them a tour, so to speak, of the car," says Ball.
He's urging the politicians he meets to consider using fuel-efficient cars for their government fleets. The mayor of Little Rock told him he'd never considered fleet purchases from a religious perspective before.
"A lot of people haven't," says Ball.
During the trip's final stop in Washington, D.C., Ball and other religious leaders plan to meet with representatives of the White House and Congress.
If and when that happens, Kara Ball sounds as if she has her speech prepared.
"I'm trying to remember the last time we put gas in the car," she says. "We left Texas, we've been in Arkansas, we certainly won't need to fill up before we get to Nashville.
"We don't give it a thought."