Traffic problems are an everyday concern in many cities,including Washington,DC.A growing number of Washingtonians are turning to bicycles to get to and from work.In fact,the number of commuters who use bicycles has doubled in the city since 2007. Ralph Buehler teaches urban planning at the Virginia Polytechnic Institute and State University,popularly known as Virginia Tech.He has written a book about urban biking,called "City Cycling". He says there is a reason why urban bike tiding is now becoming more popular. "Over the last 60 to 70 years.cities in the U.S.have been adapted to the automobile." "Most cities took advantage of the money coming for the interstate highway system,from the federal government,starting in 1956.There was a 90 percent federal match so the cities only had to put up 10%.It was very tempting." In the years after World War Two,many Americans moved to suburban communities,just outside major cities,They decided to travel great distances to and from work in exchange for a home in the suburbs.Their cars became a symbol of freedom.  But today,many people believe they can save money by living in the city.  Greg Billing is with the Washington Area Bicyclist Association."When a person makes a change from 04 using a car to using a bike,they are saving anywhere between 8 or$9,000 a year."  Ralph Buehler says governments save money when people use bicycles."Building bicycling facilities is much cheaper than building and maintaining road facilities or public transport." Washington,DC has also taken steps to protect bike riders.It approved a safe passing law and created areas on the road between cars and bikes. The United States Census Bureau says 4%of the city's workers ride to work by bike.The only city on the East Coast with more bike commuters is New York. In the years after World War Two,many Americans prefer to  _  .
1ive in the city 1ive in the suburbs travel great distances rent houses