Car Talk: Let's get the vitals out of the way. When does the show air?

Joe: "Car of the Future" airs Tuesday, April 22nd, at 8 p.m. EST, in NOVA's usual time slot. That's also when American Idol airs and when the polls close for the Pennsylvania primary. So you'll have to tear yourself away from all that madness if you want to watch some real insanity.

Car Talk: This episode of NOVA is called "Car of the Future." What sorts of ideas do Tom and Ray explore?

Joe: The big idea is pretty simple. The world is consuming oil at an alarming rate, and we need to find other ways to power cars. The big question is what can replace oil? Tom and Ray face this question on their quest to replace Tom's MG with something new and efficient.

Car Talk: What made you think of a couple of Cambridge grease monkeys, who are more used to carburetors than carbon fiber?

Joe: I wanted to treat issues like global warming and soaring energy costs as comedy. That may sound a little weird, but people are getting numbed out by these subjects, and I thought it was time for a fresh approach. So Tom and Ray came to mind. They know a lot more about cars than I do, and even if they don't have all the answers, they ask good questions.

Car Talk: We hear Tom and Ray cornered a Detroit exec at the auto show, and berated him for building high-power gas guzzlers. What happened?

Joe: Well, first, the executive happens to be a woman, and she's responsible for energy and environment. Tom and Ray wanted to understand how the company could call themselves environmentally friendly when they had so many beefy road machines on display.

Car Talk: So, 'fess up. Did she end up in the trunk of a Lincoln Town Car?

Joe: Well, it did get pretty ugly. But it was Tom and Ray who ended up in the trunk. Those Detroit auto executives really know how to take charge. I was impressed.

Car Talk: What was the most bizarre moment in the taping?

Joe: So many special moments come to mind. When we were filming in Iceland, Ray stripped down to take a dip in the Blue Lagoon. The manager thought we were shooting a porno and tried to intervene. In California, Tom and Ray got a bit carried away behind the wheel of a Tesla electric sports car and headed for Mexico. But they didn't get very far before the battery died.

Car Talk: You mentioned Iceland. What's Iceland got to do with the car of the future? Or did you just go for Iceland's fabled climate?

Joe: Actually, it was the grilled sheep's head, which is considered the best in the world. That and all the renewable energy they have from volcanic action and melting glaciers which they want to use to make hydrogen to power cars.

Car Talk: Did you realize that your trip to Iceland led to an addition to the English lexicon-- namely, Scherdling?

Joe: Not to be picky, but the term is schnerdling as in... "the boy's shnerdling and the girl's shnerdling." That's just the phonetic pronunciation. The Icelandic spelling is incomprehensible. Thank God for those pants and skirt symbols on the doors.

Car Talk: Can you tell us how it ends? Does Tommy trade up from his '52 MG-TD to one of Amory Lovins' Hypercars?

Joe: I would tell you how it ends, but then, as Ray likes to say, "I would have to kill you." You'll have to watch the show to find out what Tommy decides.

Car Talk: Will Tom and Ray's drop-dead ugly looks affect ratings? Won't most viewers run away in horror?

Joe: I have a friend named Mark who says Tom and Ray are probably better heard, not seen. I take Mark's opinion seriously. He's the director of photography for the show. Luckily, since PBS is such a big budget operation, we could afford all the latest digital wizardry from Hollywood to make Tom and Ray look halfway decent. It's miraculous what this new technology can do.

Car Talk: Before we part ways, we have to express our condolences. As folks who have to work with Tom and Ray, we feel your pain. How bad was it?

Joe: Over many years I've accumulated a lot of experience filming wildlife for the National Geographic and also little children for Mister Rogers' Neighborhood. All that experience turned out to be invaluable preparation for dealing with Tom and Ray in front of the camera.

Car Talk: Thanks for your time, Joe. If you'll excuse us now, we've got to go to the scherdling.

Joe: OK, but remember it's schnerdling. "Scherdling" means something entirely different, but if I told you what that was, I would definitely have to kill you.