It doesn't sound like greenwashing or 'brown' washing for that matter...  UPS claims to be committed to the environment and has a pretty good story to tell.  This bit is specific to their impressive and diversified fleet of alternative fuel vehicles, aka Green Trucks, currently in use.  Follow the link below to check out their other efforts towards sustainability and decide for yourself if there is enough green showing through the brown.

Green Trucks

Fuel conservation has been a priority at UPS since the early days of the company. In the 1930s, UPS pioneered the use of electric-powered vehicles in New York City, beginning the company’s legacy of pursuing cleaner and more efficient alternative fuels.

Today, UPS operates the largest private alternative fuel-fleet in the transportation industry, including hybrid electric and hydraulic hybrid, compressed natural gas, liquefied natural gas, propane, fuel cell, and electric vehicles. Through the years, countless resources and time have been devoted to numerous programs and technologies to help us meet our goal of increased fuel efficiency.

UPS operates 282 aircraft, representing the ninth largest fleet in the world. We reduce our impact on the environment by operating efficient aircraft and aggressively managing aircraft and air hub operations.

Fuel management and conservation is just one of the many ways we provide optimal service and value to our customers while minimizing our impact on the environment.

For more please visit http://www.sustainability.ups.com and ship via UPS if you feel they are more green then the alternatives.