You may have noticed that Walmart has had a recent focus on green initiatives and sustainability. They are 60% of the way to doubling their shipping efficiency by 2015. What is very interesting is that nitrogen filled tires are a part of this sustainability program.
Elizabeth Fretheim, Director of Strategy and Sustainability for Walmart's Fleet Operations says "We are rolling out a program to do nitrogen filling of tires, that will help with rolling resistance."
Walmart has realized that better pressure retention yields improved fuel efficiency and increased tire life. I have seen the raw data from the initial tests, and the results are spectactular, up to a 50% tire life improvement. The savings must be remarkable for Walmart to make the financial commitment, and invest in the nitrogen tire inflation technology at their fleet locations throughout North America.