They are heading that way in other more progressive racing series'. The Le Mans prototype cars run diesels now. The last 7 or 10 (or something) 24 hour of LeMans has been won by a diesel. They also are working on hybrid technology in both Sports car racing and Formula 1. They have this thing in F1 that takes the heat produced from braking and converts it into electricity that can then power the engine. Nascar is in the stone ages when it comes to technology. They still use push rods and carburetors, lol.
But yeah, I think the worst part of racing on the environment is 1. travel and 2. tires. A nascar race uses something like 500 sets of tires, and that doesn't count qualifying and practice. And that's just one of many races run each weekend. That's a lot of rubber. And then the travel... Each team uses probably a few haulers, and each of those has to travel around the country each week. Then there's F1. Those guys have to haul like 150 tons of equipment to each race, and they are on all corners of the globe.
Oh... in 2013 there is supposed to be an F1 race in new jersey. They are gonna have it right across from the NY skyline.