As gas prices rise, people tend to shift from driving personal vehicles to using public transit. However, the extent of this change and the interplay between fuel price spikes and transit usage are not precisely known.

In 2008 the Transportation Research Record released a study of data through 2007, “Understanding Links Between Transit Ridership and Gasoline Prices: Evidence from the United States and Australia.” The research used gasoline consumption records and public transit records to study the potential correlations between the two.

The study’s findings include:

• For every 10% increase in gas prices, U.S. transit demand has increased on average by 1.2%; demand for light rail rises by approximately 3%, compared with buses at only 0.4%.
• In Australia, the impact of gas prices on ridership has been larger, with a 2.2% raise per 10% increase in global gas prices. This is likely due to higher gas prices (20% to 30% higher than U.S. prices).
• In general, increased gas prices had a much larger effect on increasing demand for public transit for longer — rather than shorter-distance — trips.

A related study, “Potential Impact of Gasoline Price Increases on U.S. Public Transportation Ridership, 2011-2012” (PDF), looks at how future gasoline price increases might affect transit usage in the United States.

Tags: cars, consumer affairs, fossil fuels, mass transit, municipal