Driving around his Robbinsville neighborhood or in his native Hamilton, John Holden couldn’t help but wonder what was behind all the closed garage doors.

He has started to find out in the past year, thanks to some old friendships, a Web site and a hobby that’s growing in popularity.

A year ago, Holden started the Robbinsville Hotrods club with a Web site and message board (robbinsvillehotrods.com) intended to reconnect him with people he hadn’t seen since he was a teenager.

He passed out fliers for his new creation at various car shows in the area, hoping some of the guys he hung out with in high school would still be into the hobby and would see the advertisement.

Not only did his old friends find out about the Robbinsville Hotrods, but people in his neighborhood did as well. The Web site has about 200 regular users, and some of the members occasionally meet up with their cars, like a handful did at the Robbinsville St. Patrick’s Day Parade March 21. Turns out hot rods are more popular than even Holden expected.

“I’ve been involved in cars since I was a teenager, and I lost track of a lot of the friends I had,” Holden said. “I thought it was a good way to bring people together. I’m trying to attract people who have been in the hobby for years. All of these people are neighbors. You just never know what’s behind their garage door.”

Holden always had a curiosity when it came to cars. As a teen in Hamilton, he worked on cars with friends, and they’d look to each other for advice in fixing particularly tricky problems or finding the best spots to show off their cars.

They all grew up, some moved away and Holden realized, during the last 20 years, he had lost touch with a lot of the friends he had made as part of that scene. But his love of cars hadn’t waned, and Holden guessed neither did the enthusiasm of his old friends.

Holden and some of his friends had stayed in contact through a car club called the Hamilton Knights, but many separated as time passed.

The Hamilton Knights hope to experience a bit of resurgence thanks to the Web site. The group has its own section on the message boards, where discussions range from club T-shirts to its twice yearly trip to Wildwood.

Knights made up much of the initial audience for the Robbinsville Hotrods Web site. They and others use it now to post photos of their cars, chat about problems and arrange get-togethers.

With the recent warm weather, talk on the message board has started about weekly cruise nights in the area. One at the Kmart on Whitehorse-Mercerville Road in Hamilton happens every Monday once the weather turns nice. People usually start coming out with their cars in early April, Holden said.

Cruise nights and the Hamilton Knights aren’t new, but the popularity of hot rods in the area wasn’t fully apparent until people on the Robbinsville Hotrods message board started talking about where they lived.

“I was surprised,” said Eric Oldenburg, a Hamilton Knights member and Robbinsville resident. “The amount of people who live around here is astounding. It’s amazing the number of cars there are and the number of enthusiastic people there are in the area.”

Hamilton native Mike Meighan, a longtime Hamilton Knight, said that trend has led to a greater acceptance of hot rods. He expects the popularity of older cars to continue growing and Web sites like Robbinsville Hotrods to foster a sense of community.

He said he posted on the Web site that he needed a part for a car he was working on, and someone had the part. The person with the part turned out to live near Meighan.

“In the last five to 10 years, there’s been a resurgence of the older muscle cars,” Meighan said. “There are a lot of guys who have the cars in their garages, and muscle cars get a little more respect on the road. About 20 years ago, the tolerance was lower. Now people know it’s going to be louder than a 2010 car in the showroom.”

As if to display that point, there are plenty of new members in the group, as well. Several are high school students who are working on cars with their fathers.

Robbinsville High School senior Matt Tindall received and began working on his first car, a 1968 Chevelle, when he was 15. He has been working on a 1930 Ford recently. His interest in cars led him to pursue a major in mechanical engineering next year at Lafayette College.

The Web site has introduced Tindall to car enthusiasts in the area he wouldn’t have known otherwise. It’s nice to know people locally who share your hobby, whether it’s for advice, exchanging parts or merely camaraderie, he said. He expects that circle to grow.

“You’re going to see more of it,” Tindall said. “People appreciate seeing something that’s 40 years old.”

Holden intends his group to be the place for all those who appreciate cars.

Everyone in the group has some sort of restoration project, but not everyone is at the point where their car can be driven. Some may be discouraged from joining Robbinsville Hotrods because of the state of their car, but Holden that shouldn’t be the case.

Anyone that has worked on a car understands the work and time required to get it going again, let alone looking good.

“We don’t care if your car looks like a million bucks,” Holden said. “It doesn’t even have to be painted. They have just as much fun as the guys who spent $100,000 to restore. We really don’t care if your car is finished. It’s all about having fun.”