The world produced an estimated 130 million bicycles in 2007 -- more than twice the 52 million cars produced. Bicycle and car production tracked each other closely in the mid-to-late 1960s, but bike output separated sharply from that of cars in 1970, beginning its steep climb to 105 million in 1988. Following a slowdown between 1989 and 2001, bike production has regained steam, increasing in each of the last six years. Much of the recent growth has been driven by the rise in electric, or "e-bike" production, which has doubled since 2004 to 21 million units in 2007. Overall, since 1970, bicycle output has nearly quadrupled, while car production has roughly doubled. Promoting the bike as a clean and efficient alternative to the personal automobile is a practical way for cities to reduce traffic congestion and smog. To simultaneously confront those problems as well as climate change and an emerging obesity epidemic, government leaders and advocacy groups are working to bring cycling back to prominence in the urban transport mix. A number of European cities have set the standard for bicycle use and promotion, via pro-bike transportation and land use policies, as well as heavy funding for bicycle infrastructure and public education. In Copenhagen, for example, 36 percent of commuters bike to work. The city plans to invest more than $200 million in bike facilities between 2006 and 2024 and estimates that by 2015 half its residents will bike to work or school. In Amsterdam, cycling accounts for 55 percent of journeys to jobs that are less than 7.5 kilometers (4.7 miles) from home. The government has pledged to spend $160 million from 2006 to 2010 on bicycle paths, parking, and safety. And Freiburg, Germany, a city with 218,000 people, has allocated roughly $1.3 million annually for cycling since 1976; now some 70 percent of local trips there are made by bike, on foot, or by public transit. Governments elsewhere are following Europe's lead. Bogota, Colombia, boasts more than 300 kilometers of bikeways, the most for a city in the developing world. In Australia, the state of Victoria has amended planning laws to require all new large buildings to provide bike parking and other facilities such as showers and lockers. And in November 2007, South Korea's Home Affairs Ministry announced a new pro-bike campaign to alleviate increasing traffic and air pollution and to cope with soaring oil prices. As it expands bicycle infrastructure, the government aims to substantially increase bike ownership by 2015, from one bike for every seven citizens to one for every four. Some notoriously polluted and congested cities are working to reap the benefits of cycling as well. Mexico City plans to have 5 percent of all trips be by bike in 2012, up from less than 2 percent today, using traffic calming methods, promotional campaigns, and bike-transit connectivity. In India, Delhi's newest Master Plan requires fully segregated bicycle tracks on all arterial roads and notes that promoting cycling will be an essential component of the city's plans to reduce growth in fossil fuel consumption. (See additional examples of bicycle promotion initiatives.) Bicycle rental programs are also increasing bike use in some cities. The stand-out example of 2007 was Paris's low-cost Valib rental scheme, launched in July. Now offering 20,600 bikes that can be obtained by credit card at 1,451 stations, the program logged 6 million rides in its first three months. Analysts expect the program to double or even triple bike trips in Paris. Similar programs exist in Oslo, Barcelona, and Brussels and are planned for Washington, D.C., and central London, among other cities. While biking remains popular for recreation in the United States, it is woefully underused for transportation. Total cycling participation has declined nationally since 1960, dropping 32 percent since the early 1990s, and now accounts for just 0.9 percent of all trips. Cycling to work is even less frequent, at 0.4 percent of trips. Despite these unimpressive statistics, encouraging signs can be seen for the future of cycling in the United States. Aided by $900 million a year in federal funding for promotion of biking and walking for 2005 to 2009, the installation of bicycle facilities -- including parking, bike-friendly roads, and designated lanes -- is proceeding at a record pace. Indeed, plans in the 50 largest U.S. cities would, on average, double their bicycle and pedestrian routes; New York City alone will quadruple its bike network to 2,900 kilometers by 2030. Bicycle advocacy in the United States continues to grow as well. The League of American Bicyclists now honors 84 U.S. towns and cities as Bicycle Friendly Communities, compared with 52 in 2005. Cycling advocacy groups operate in 49 states and Washington, D.C. Perhaps most exciting, a Complete Streets movement has blossomed in recent years, in which a broad coalition of citizen and environmental groups is calling for safer, pedestrian- and cyclist-friendly roads designed for everyone, not just cars. Six states and more than 50 cities, counties, and metro regions have now enacted some form of Complete Streets legislation. For example, the Illinois General Assembly voted last October to require all new state transportation construction projects in and around urban areas to include bicycle and pedestrian ways. While the bicycle is still an essential form of transportation in China, the country has recently seen a rapid decrease in bike ownership as its population becomes wealthier and turns to cars. From 1995 to 2005, China's bike fleet declined by 35 percent, from 670 million to 435 million, while private car ownership more than doubled, from 4.2 million to 8.9 million. Blaming cyclists for increasing accidents and congestion, some city governments have closed bike lanes. Shanghai even banned bicycles from certain downtown roads in 2004. This deterioration in Chinese bike culture emerges even as the country's share of world bicycle production continues to rise: China now turns out more than four fifths of the 130 million bikes produced each year. China's central government, increasingly concerned about traffic congestion, energy consumption, and people's health, has now begun calling on cities to reverse this discouragement of bikes. In June 2006, Deputy Minister of Construction Qiu Baoxing ordered cities that had narrowed or removed bike lanes to restore them. Within Beijing, bike promotion is having some visible effects as the city prepares for the 2008 Olympics. For example, after successful pilot projects, a private bike rental scheme co-sponsored by Beijing's environmental protection and security bureaus aims to provide 50,000 bikes at some 200 locations by August. Thus far, however, the recent pro-bicycle rhetoric from Beijing has not translated into much positive action outside the capital. Development projects addressing disease and poverty in Africa provide evidence that the bicycle's utility is not just limited to urban areas. In Zambia, World Bicycle Relief has partnered with a coalition of relief organizations to combat HIV/AIDS through more timely education and treatment, providing 23,000 bicycles to healthcare volunteers, disease prevention educators, and families affected by the virus. In Burkina Faso, Ghana, and Uganda, an alliance of Dutch non-governmental organizations has launched a micro-credit lending program called Cycling Out of Poverty. Through this effort, poor people can pay off leased bikes while using them to attend school or start a small business. With more than half the world's population now living in cities, there is tremendous potential for municipal governments and urban planners to increase bicycle use by following classic European examples like Copenhagen and Amsterdam. These cities have shown that by integrating bicycles in transportation planning, educating the public about cycling's benefits, and discouraging driving with restrictions and taxes on car ownership and parking, governments can greatly enhance bicycle use. This promotes people's physical fitness while helping to create cleaner, more livable communities.