Yahoo held a huge bike fair at their Sunnyvale headquarters last week. The bike fair was organized to encourage bicycling as transportation. Specialized, local bike shop Mike’s Bikes and the Silicon Valley Bicycle Coalition were on hand to display bikes and help people with bike commute routes.

Five lucky Yahoo employees also won a special Yahoo edition of the Specialized Globe Comp IG8 bicycle. The Globe Comp IG8 is a commuter bike with Shimano’s Nexus 8 speed hub in the rear wheel, carbon fiber front fork with fender mounts, and 700×42 flat resistant street tires.

That purple bike is pretty hard to miss; I ran into one of the lucky winners — Daniel — at the Caltrain station in Mountain View, California last night and learned about the Yahoo bike fair.

Cleantech blog notes that Yahoo! is among the most successful when it comes to encouraging Yahoos to use alternate means of transportation:

36% of Yahoo headquarters employees get to work without driving solo. This is double the 18% mode-shift that the corporation committed to the City of Sunnyvale when building permits were first issued. Yahoo’s cool commute program is comprehensive, popular and getting results.

Yahoo provides employees with free VTA Eco-Passes for bus and light-rail. Many of the Yahoo commuters are able to get extra work done using laptops and other mobile devices while commuting on public transit.

Yahoo’s results are impressive considering that Silicon Valley workers are widely dispersed in search of affordable housing. Technologists work long and irregular hours, which makes ridesharing more challenging. Many Silicon Valley locations provide a long and uncomfortable walk in the dark to public transit.

Yahoo addresses these problems in a number of ways. One is that it provides a guaranteed ride home. Yahoo will pay for a late worker’s taxi or rental car. Many at the workshop agreed that a guaranteed ride home is critical to a commute programs success. All agreed that employees rarely use the guarantee, making the cost minimal.

Yahoo has a fleet of shuttles to get people to and from transit, between Yahoo locations, to airports and sometimes providing an emergency ride. Some of the shuttles run on B20 biodiesel.

It is not easy to get employees to change their commuting behavior. Yahoo used surveys, education, an intranet website to help people find others for ridesharing, and YahooGroups to encourage collaboration, and monthly reward competition for those who avoid driving solo.

Yahoo encourages the use of the zero-emission vehicle owned by one billion people on this planet – the bicycle. Yahoo provides bicycler riders with secure storage of their bikes. Free lockers and showers are available. To help people quickly navigate Yahoo’s campus of buildings, loaner bikes are also available.