IBM was one of the first global companies to pioneer programs to reduce employee commuting. It has sustained these programs for nearly two decades. Two key aspects are its (a) work-at-home program and (b) mobile employees program. In 2013, 105,000 of our 431,000 global employees participated in one of these two programs, which not only helps employees balance their work and personal responsibilities, but also benefits the environment. In the United States alone, IBM's work-at-home program conserved approximately 5.6 million gallons of fuel and avoided more than 44,000 metric tons of CO2 emissions in 2013.
IBM joined the reconstituted United States Best Workplaces for CommutersSM (BWC) program in 2009. Currently, 22 IBM locations are registered as Center for Urban Transportation Research BWC sites, which represent approximately 60 percent of the company's United States employees. Many locations actively work with their local or regional transit commissions to integrate IBM's programs with regional programs to increase commuting options for the company's employees. Globally, many of our locations provide support for the use of public transit systems, including shuttles from locations to mass transit stations, and alternate transportation or "loaner" cars for business trips during the workday.
In some countries, IBM provides leased vehicles for employees that they may use for both business and personal purposes. For these vehicles, we continue our effort to move to more fuel-efficient models by setting standard guidelines for smaller engine sizes with lower emissions profiles. These guidelines enable reductions in average car emission levels as their car fleets are renewed. For the cars our employees rent while travelling for business, we have worked with rental car companies to require and/or offer more fuel-efficient vehicles for employee rentals.