As a substitute for automobile travel, bicycling provides significant social, environmental, and economic benefits, including congestion mitigation, reduced travel costs, mobility for non-driving populations, increased transit access and ridership, and improved community livability.

Bikeways can offer an alternative to passenger cars. Local trips using passenger cars now clog our arterial and expressway systems with short trips and turning vehicles. In Chicago, 31% of trips are less than one mile in length; 59% are less than three miles long, an easy distance by bike. In the suburbs, 20% of trips are less than a mile; and 51% of trips are less than three miles long. (CATS 2004)

The degree to which increased bicycling reduces congestion has not been firmly established in planning literature. Litman estimates that adding an additional automobile to peak-hour traffic in an urbanized area results in external costs to other travelers (made up of incremental travel time increases and other factors) of 10 cents to 35 cents per mile. (Litman 2004, p. 9) If that traveler used a bicycle instead of an automobile, these costs to other users decrease dramatically.

There are many benefits of integrating bicycle, pedestrian, and transit methods of travel. Transit enables the bicyclist or pedestrian to take longer trips and to pass over or through topographical barriers. Similarly, adequate non-motorized facilities enlarge transit's catchment area. Good bicycling and walking facilities that complement a comprehensive transit system create a Transportation synergy that can provide people access to work, school, shopping, and other desirable destinations, while at the same time relieving automobile congestion on the roadways.

For example, in the state of California, after bike racks were installed on Caltrain (the San Fransisco-San Jose commuter rail system) a 4% ridership increase was attributed to bicyclists (Ciccarelli, 1998). In 1999, Denver's Regional Transportation District (RTD) conducted a survey of bicyclists who utilized the bike racks on buses. Survey results showed that approximately 50% of the bike-on-bus riders would not make the trip on transit if it were not for bike racks. (Epperson, 1999)

The Federal Highway Administration has also studied this issue and has determined that there are examples of transit ridership increasing due to increases in bicycle facilities. In Phoenix, a bike-on-bus demonstration program led to over 1,400 new transit riders per month. (FHWA, p. 5) The same report also stated that bike-on-transit services were often used by riders during off-peak times, making more efficient use of transit capacity. Also, as noted above, programs that link biking and transit expand the catchment area of public transit and allow bicyclists to make trips that they otherwise could not have made. (FHWA, p. 9)