All major American cities offer some form of public transportation, but for many urban dwellers, the limited infrastructure comes up short. Ten block walks to the bus stop in bad weather is not fun. And transporting furniture or groceries home from the store is not possible. There are very few cities where there is not a compelling practical advantage to having a car. But a new trend in transportation has many citizens rejecting personal automobile ownership in favor of car sharing services like Zipcar.

Founded in 2000, Zipcar now boasts 180,000 members who pay a $50 annual membership fee for access to cars in more than 50 cities across the United States. For $11 an hour, members can pick up their cars from designated parking spots around the city and keep them for as long as they need—gas and insurance included. Since gas is included in the price, Zipcar has a major incentive to use as many fuel-efficient vehicles as possible, with the majority of rentals coming from hybrids and other high gas mileage vehicles. Zipcar says that 40 percent of their customers choose to either sell their cars or forgo purchasing a new car.

The idea of sharing your wheels is spreading in surprising ways—to bicycles. The first major municipal bike sharing system was recently unveiled in Washington. D.C. The district teamed up with Clear Channel—which manages the city’s bus shelters—to create a high-tech bicycle sharing program. For $40 a year, residents can pick up the bikes—which are locked to bus shelters around the city—and borrow them for several hours at a time. Other cities like Portland are exploring similar projects, and bicycle sharing has been a huge hit in Europe for years, where the first successful program was launched in France in 1974.

As owning and driving a car continues to grow in cost, consumers will increasingly seek out more fuel-efficient cars. If the costs—to individuals and society—grow to dizzying heights, consumers may start to entirely ditch their vehicles in exchange for any number of shared transportation alternatives.