Innovation takes many roads -- seldom as quickly as a California man who is building what may be the fastest street-legal green car in the world, or just the fastest car.

The last time I talked to Mike Pethel on the radio, this is what he told me: "The car is going to be on the road soon and it's going to be fast. It's going to be really fast."

Well, I'd heard that. I met Mike a year-and-a-half ago in a neighborhood garage. Ever since, I've been watching him transform an old BMW into maybe the fastest green street-car in the world.

It was almost done a couple of months ago -- the hood missing -- when...umm, if the sheriff is listening, I'm not saying this did happen. But if it did, it went like this:

Evening on a long, straight nearby street. Nobody walks here, no dogs, not much traffic. There's a row of cars parallel-parked in front of two story condos on the right. Up ahead, maybe 300 feet, a dark Mercedes is backing into an open space, the car paused, like it can't decide about starting over.

Nothing else on the road.

We ease forward, 20 feet, and he hits the throttle.

I feel the car bulge like a pumped muscle, and we are going unbelievably fast, unbelievably quickly.

The Mercedes is still frozen half in our lane up ahead. Not ahead anymore...we are on it, doing about 80.

Mike twitches the steering wheel. The BMW jumps a half-step left, past the other car, and the back breaks free. We're sliding. He touches the throttle again. Almost like he's thinking it, the car leaps forward and grabs a straight line into the roadway ahead.

It's supercar.

...If it happened...

Three months later, I'm at Elco Welding in Venice, Calif., where Mike lives. A lot of the work gets done in this shrine to the machine age. The BMW is on a lift.

"So what I was worried about is this piece right here," Mike says.

Mike wants to change the mechanical assembly that connects the drive shaft to the rear wheels. The car is powerful enough to tear itself apart; this is where the stress will show.

"The last couple of times I took off really aggressively it seemed to act differently," he says. "And I thought, 'if I'm going to give some rides, I don't want it to go shooting sideways, you know, for any reason." He laughs.

He's an obsessive, remaking the BMW for extreme performance. But in the months I've watched the project, I've come to think his real goal is innovation itself -- rethinking cars. He's developed new motors; they can run a racecar or a bread truck, he says -- it's all in the tweaks. This from a no-college techno-savant turned radical green.

"When I was 12 years old, I was making electric cars out of little wooden toys that I would buy," he says. "I can visualize electron flow and impedances and I can know how coils and capacitors work, basic electronic components that are easy to understand."

Easy for him. His technical skills afford him his means. He co-founded a big digital production house in L.A. -- Company 3, where he works on films and ad campaigns. He loves speed, but not the commercials he made for cars that were noisy and dirty.

"I just wanted something really clean that I wouldn't have a problem driving around," he says.

He began with an early '70s BMW classic, a 3.0 CS, a car he and his dad swapped back and forth for years. That's how it still looks, the polished light pewter body like a greyhound at rest.

Under the hood, the engine compartment looks bare. The pair of electric motors are a fraction the size of a big gas engine.

Tesla and other electrics run on alternating current -- AC. Mike's are direct current, DC, built to his design. No others like them are known.

"The DC motor is really kind of a primitive device, but it works," Mike says. "Can't not work; magnetic fields work; electrons work; you put a force in there and it turns the motor...so...it's easier to make a DC motor work."

And it works really great if you connect it to 2,400 lithium-iron phosphate cells in three custom boxes made from bullet-proof glass, one megawatt of energy. One million watts, enough to run 750 homes -- in one car, an insane amount of power.

The car is ready again. Let's see how it does...

You probably do not want this car. It uses power so quickly it needs a recharge every 50 miles or so. But that's the design: supercar as extreme daily driver. It's how Mike goes to work, five miles in a stock-looking, elegant automobile -- with 800 horsepower.

You don't want this car. But you might like another version. You can make a DC motor do whatever you want. Or Mike can. Maybe that's where this innovation leads. Electrics are coming, Mike Pethel says, like his car, or not.

"I mean, if I just had a really loud car, it might be exciting to some motorhead. But when you have an electric green, clean, quiet car, everybody likes it."