My hat's off to Tom Altenhoff, 46, who needed to run errands after work Tuesday night. Altenhoff, who works for Hennepin County Human Services, pulled on his wool hat and turned up his coat collar before walking for nearly 30 minutes in the 14-degree wind chill from the Hennepin County Government Center. In a parking lot at Nicollet and Groveland, he jumped into a light blue Toyota Prius and off he went.

Altenhoff isn't a car owner, or a car thief. He's quietly taking part in a Twin Cities revolution that is sneaking up on an impressive milestone.

Begun five years ago with $360,000 in private and government funding, Hourcar (www.hourcar.org) provides hourly access to a fleet of cars that are way cleaner than mine. The nonprofit, run by the St. Paul-based Neighborhood Energy Connection, is closing in on its 1,000th member. That may pale compared with car-sharing hot spots such as San Francisco and Chicago, but it's impressive considering how much we Minnesotans love our cars.

"Five years ago," said a laughing Christopher Bineham, Hourcar's program manager, "people asked us, 'What are you guys thinking?'... Starting out, we thought it would be bigger at this point."

Still, Bineham said, people are growing hungrier for "these sorts of options. There's been a shift," he said. "People are starting to get it," for environmental reasons, certainly, but also because of the freedom not having a car provides.

"A lot of our early members had the environment as their top-of-mind issue," Bineham said. "In the last couple of years, people are happy to support the environmental issue, but it really is a lifestyle issue. They love the multi-modal option of 10 minutes of reading on the bus, and biking and walking," grabbing a car only when they really need it. In fact, he noted that the average American car sits unused 23 hours a day.

Hourcar's membership is more diverse than you might expect. The largest group is evenly spread out among those age 25 to 50, (you must be at least 18), with another bump around 60. That, Bineham theorizes, "is when the kids are grown and people say, 'I want to come back downtown and walk everywhere.'"

Two-thirds live in Minneapolis, one-third in St. Paul. Slightly more members are female. Most live and work in or near the two downtowns, but a few hail from first-ring suburbs and combine Hourcar with busing and biking.

Hourcar members, who pay a nominal monthly fee ($5-$15), can choose from two plans, based on how car-reliant they are. Altenhoff, who lives and works in downtown Minneapolis, is on the lighter "freedom" plan, paying $8 an hour and 25 cents per mile (about $35 a month). Heavier users might choose the "go" plan, which charges a daily rate of $55 on weekdays and $65 on weekends. Gas and insurance are included.

Becky Alper, 26, is on the latter plan. She used a similar service in Boston, called Zipcar, and just returned to her hometown of St. Paul in May. She and her husband spend $150 to $200 a month with Hourcar, taking it to shop for groceries, join friends in Minneapolis' Uptown, or pick up family at the airport. Using Hourcar, as well as walking and riding the bus, Alper said, "encourages me to get to know the city better, to plan ahead a little. And I don't have to deal with any car maintenance."

The 23 cars, all automatic hybrids, are parked strategically throughout the cities, usually on bus lines. You can reserve up to three months in advance, but often on an hour's notice. Smoking is out. Bike racks are OK. You can bring your pet as long as it remains in its carrier.

Get a ticket? You pay. Get in an accident? Hourcar deals with that. Going to be late? Call immediately. Need to clean the car after use? No, but please remove wrappers. Your mother doesn't chauffeur here.

Altenhoff started using Hourcar in 2007 but he has lived without a car since 1997.

"When I first started with Hourcar, I underestimated how much time I'd need," he said. "I was constantly calling and asking, 'Can I extend for another 15 or 30 minutes?'" (There's a charge for that.) Now he builds in a "luxurious" cushion and packs his errands into one trip.

On Tuesday, he delivered boxes to a Minneapolis school, where he volunteers, then stopped for cat food. After that was an exciting stop to fill up the tank using an Hourcar gas card. Members are only required to do so if the tank is less than one-quarter full.

Although he could afford to own a car, Altenhoff prefers this route. "I'm usually able to get a reservation even on the same day," he said. "If that ever changes, I might consider buying a car. But I've gotten pretty used to not having a vehicle."

Gail Rosenblum • 612-673-7350 • gail.rosenblum@startribune.com