Waste Management, a company we are all aware of, has been leading the way for the trucking industry to switch from Diesel to cleaner burning Natural Gas. Here is a quote from the following article from The Wall Street Journal:

Rising diesel costs last year forced Waste Management Inc.
WM +1.33%to charge customers an extra $169
million, just to keep its garbage trucks fueled. This year, the nation's biggest
trash hauler has a new defensive strategy: it is buying trucks that will run on
cheaper natural gas.

In fact, the company says 80% of the trucks it purchases during the next five
years will be fueled by natural gas. Though the vehicles cost about $30,000 more
than conventional diesel models, each will save $27,000-a-year or more in fuel,
says Eric Woods, head of fleet logistics for Waste Management. By 2017, the
company expects to burn more natural gas than diesel.

http://online.wsj.com/article/SB10001424052702304707604577422192910235090.html

The video featured in the beginning of the article is very interesting so make sure you watch it too.