By Scott Doggett, Contributor Ask a Tesla Roadster owner why he drives one and invariably you'll be told it's for the environment. Mother Nature, you think. Climate change. Polar bears. And that's half true. Maybe even three-quarters true. But drive a Tesla Roadster – especially the 2010 Tesla Roadster Sport – and you soon learn about the other environment, the one few motorists know. Here are a few examples of what that environment looks like: In the next lane, at a stoplight on a road that skirts Stanford University, a smirking Corvette ZR1 owner revs his otherworldly 638-horsepower 7.0-liter V8. You twist the key in your ignition forward an eighth of a turn, which instantly switches the drive mode from Standard to Performance. The traffic signal changes, you and the 'Vette driver floor it. Three seconds later the powerful Chevrolet is occupying space in your rear-view mirror. Traction-control limitations. The Chevy salesman probably forgot to mention them to the now-frowning ZR1 owner. Then there's the blue Infiniti G37 Sport 6MT with the close-ratio six-speed manual transmission and the short-throw shifter, one lane over on the 101 Freeway approaching San Francisco, Candlestick Park on the right. He's playful, as are you, and just like the Corvette driver soon he, too, is a shrinking part of the landscape behind you despite his best efforts to outpace and then just keep up. And then there's the Miata owner, poor thing, taking a sweeping onramp as quickly as possible, white…