D.C. drivers can finally settle the argument over whether buying a car in the city is worth the money. An analysis by personal finance site NerdWallet, posted on Monday, records the tipping point where owning a car becomes cheaper than using car-sharing services like Zipcar in 15 major U.S. cities including D.C.

The data is based on a hypothetical 27-year-old person who doesn’t need a car to commute to work, but drives a 2012 Toyota Camry on weekends. Here, a “trip” consists of driving 30 miles from 10 a.m. to 5 p.m. on a weekend day.

The results: To justify the cost of owning a car over car-sharing in the District, you would need to take at least 18 Zipcar trips within a year. Drivers making monthly loan payments on a car, on the other hand, would need to take at least 46 Zipcar trips per year for owning a car to be the better option.

Generally, NerdWallet recommends car-sharing as a cost-effective option for drivers who only need a car occasionally, such as on the weekend. On an hourly or daily basis, however, the rates to use Zipcar exceed the costs of owning a car.

The results differ widely among cities due to differences in cost of gas, insurance rates, and Zipcar rates. For example, because Zipcar rates are highest in New York City, it takes only 38 weekend trips to justify owning a car if you’re making payments on a loan—the lowest number out of all the cities tested.

NerdWallet points out that the study doesn’t take into account convenience factors—such as access to parking—or public transit options. Drivers should also keep in mind that results may vary depending on your preferred car-sharing service.

The report is based on Zipcar rates, where a day trip on a weekend day in D.C. costs $90.48 and membership costs $70 per year. With Enterprise CarShare, on the other hand, costs are slightly cheaper in the District—starting at $7 per hour or $81 per day for a weekend trip, plus annual membership starting at $40. Finally, a weekend trip with Car2Go will set you back $14.99 per hour or $84.99 per day plus a one-time $35 registration fee.

Photo by Darrow Montgomery