We imagine some readers will be surprised by this. Newsweek has just put out its rankings for the top "green" companies in the world, and while Tesla Motors chief Elon Musk can crow about how green his electric vehicles are, the company as a whole apparently falls behind some traditional automakers. Quite a few of them, actually.In Newsweek's Global 500 list of the greenest 500 largest publicly-traded companies in the world, BMW ranked best among automakers at Number 26. Not surprisingly, Toyota was close behind at 35, while Nissan came in at 152. What's a little more puzzling is that Tesla fell behind Ford (178), and General Motors (289). That's a lot of pickups versus a few Model S EVs. Go figure. Then came Hyundai (306) and Honda (316), which are a little more palatable. Tesla? It came in at 431.Newsweek's measurement standards include eight categories that include a lot of verbiage and involve things like energy productivity (which is defined as revenue in US dollars divided by total energy consumption), greenhouse-gas emissions productivity (revenue divided by GHG emissions), water usage, waste levels and something called "green revenue" (revenue derived from products that "contribute positively" to the environment). Newsweek says that its results are reproducable by a third party. Take a look at the list here and find the details on how the numbers are compiled here