More Americans than ever are riding their bicycles to work instead of driving. They are doing this because of gas prices, a slowing economy and concerns about the environment.

Many Americans have been leaving their cars at home and riding to work on bicycles. Andy Clark is the executive director of the League of American Bicyclists. His group supports bicycling for fun, fitness and transportation.

Mister Clark says this is good news for the environment. He says riding a bicycle to work does not burn fossil fuel or create dangerous pollutants. Experts say the effects are the most important on short trips. The Department of Transportation says fifty percent of Americans drive eight kilometers or fewer to work.

Shorter car trips release more pollution into the air for each kilometer driven. This is because the device in a car engine that reduces the harmfulness of emissions needs to warm up before it can work well.

Members of Congress have supported bicycling as environmentally friendly transportation. For example, Minnesota Representative James Oberstar is a strong supporter of bicycle use. He says cities, counties, state governments and state highway transportation agencies are planning the roadways of the future. They are creating roads and paths for bicycles in cities and between communities.

Last year, the Pacific Northwest city of Portland, Oregon, had the highest percentage of bicycle commuters in the United States. Portland has been doing progressive city planning for many years to create special paths for bike riders.

Andrew Land is one of Portland's citizens who bikes to work every day. Mister Land is thirty-three years old and has never owned a car. He has biked to work for twelve years. Before moving to Portland six years ago, he lived in Washington, D.C. But he was hit by a car twice while biking to work there.

That has not happened in Portland where there are special roads for bicycles. Mister Land bought a house near these special bike lanes. He rides almost five kilometers to work each day. He also uses the sixty-four kilometer bike path around the city.

Andrew Land rides a cyclocross bike. He says it combines the best parts of a racing bike and a mountain bike. You might say that Andrew Land is "into bikes." He recently attended a show of handmade bicycle frames. It was organized by thirty bicycle frame builders in Portland. And he attended a legal rights workshop for bicyclists.