Spot checked about 10 places along the b2177 on Google maps and I didn't come across a single piece of double white line, so unless it has changed significantly lately I doubt it is a significant problem.
Also, let's be frank, if you go out in a pollution causing vehicle and create pollution, that is down to you, not anyone else. If you care that much, go buy a Prius or something rather than point the blame at others.
Edit - http://everyaccident.co.uk/road-b2177 seems to be about 40 accidents a year on that road, seems to me that they must be causing quite a bit of pollution and congestion? Also seems to have fatalities more years than not. Perhaps the speed limit should be knocked down to 20 or 30?