To share or not to share?

A national study released this week looked at the cost of car-sharing services compared with car ownership in an effort to help drivers decide which option would be best for them.

"It actually makes a pretty compelling picture that maybe you shouldn't own a car," said Victoria Simons, author of the study by the personal finance website NerdWallet.

The study gives some context for urban residents trying to figure out whether car ownership is worth it, said Mike Boyer, manager of long-range planning for the Delaware Valley Regional Planning Commission, and highlights the increasing options available for people trying to get around the city.

"Sort of in the big picture, and looking to the future, I think [car sharing] is another option, it's another alternative for people to get around," he said.

The study looked at how many rides a person could pay using Zipcar, a popular car-share company, with the money a driver might spend on a car over the course of a year in 15 major urban areas. In Philadelphia, a person still paying a car loan could instead pay for 46 Zipcar rides, each about 30 miles long. A person who owns a car outright could take 19 Zipcar rides for the annual cost of automobile insurance and gas.

Parking and maintenance costs vary widely and were not factored into the study.

In Philadelphia, a 30-mile weekend trip in a Zipcar costs about $92. An annual Zipcar membership costs $70.

Amanda Leahy, 37, was a Zipcar user for years before deciding last year to lease a car. She liked Zipcar's service for chores such as getting groceries, when walking with heavy bags was too hard and taking the train too expensive. But she says she found the cars sparsely spaced in her Mount Airy neighborhood, sometimes up to a mile away. A few summers doing a lot of driving convinced her that the challenges of being car free outweighed the benefits.

"When you add up all those costs with going to the beach and the other trips and going to visit family," she said, "you've already got a lease there."

Zipcar car-sharing has been in Philadelphia since 2007, company spokeswoman Lindsay Wester said. The company has about 430 vehicles operating in the city at any time, she said, 100 more than at this time last year.

"Adding 100 vehicles in a year is a large number and due to significant demand in the city of Philadelphia," she said.

In Philadelphia, Zipcar members are directed to available cars by a map and must return the vehicles to the parking spots where they found them. The service is not ideal for commuters who drive to work daily, since it charges an hourly rate, but is a good companion to robust public transportation networks, Wester said.

"Our mission has been to enable simple and responsible urban living," she said.

Car-share businesses are among the transportation options that have blossomed in Philadelphia in the past 15 years. The city's rail network has reported growing ridership and a bike-share program new to the city this year is expanding. Competition with ride-share services is driving businesses such as Uber and Lyft, which are also challenging the city's taxis.

"In the future I think a key is going to be to provide information to the people which is the best option for that day," Boyer said.