One-Way Car Sharing Gains Momentum BERLIN - Marc Clemens, founder and chief executive of Sommelier Privé, an online wine service, gave up owning a car a year and half ago. When he wants to drive to work in the morning, he checks his smartphone to see where a particular BMW, Smart car or Mini is parked and takes it. Once he gets to his destination, Mr. Clemens parks the car on the street and forgets about it. He relies exclusively on two car sharing services, DriveNow and Car2Go. "I use this three to four times a day," he said, as he dropped off a colleague in front of a wine bar in the German capital's Mitte district on a recent Sunday evening. To get to work, for business meetings, going out to a bar. I like it because it's one-way. Car sharing has been around for decades in Europe and has caught on in the United States with Zipcar. These station-based car-sharing services require members to pick up vehicles from a particular place, which may or may not be convenient. Users usually need to reserve cars in advance for prearranged, prepaid blocks of time and, when they are done with the car, they have to return it to the same place - all factors that have limited car sharing's attractiveness. Berlin, though, has become the largest one-way car sharing city in the world. One-way or free-floating services, which recently started in the United States, use GPS and smartphone apps for far more flexible car sharing. Cars are parked on city streets, and users pick up cars parked nearest them. Instead of bringing the car back to a lot, users leave it wherever they find parking near their destination. They are charged for the amount of time they spend driving. These new systems have been making an impression. Since the first commercial one-way car sharing systems started in Germany two years ago, 183,000 people have signed up, according to Bundesverband CarSharing - a large number, considering that long-established car sharing systems in Germany have 262,000 members. Car2Go has started service in 11 North American cities including Austin, Tex., Seattle and the District of Columbia. DriveNow is in San Francisco, but it uses the older station-based model. "It's going to alter what car sharing is," said Susan Shaheen, co-director of the Transportation Sustainability Research Center at the University of California, Berkeley."We didn't have the technology to do this in the "90s." Two of Germany's biggest automakers are squarely behind the idea. DriveNow is a joint venture of BMW and the car rental company Sixt, and Car2Go is a subsidiary of Daimler. In the United States, DriveNow is solely BMW's venture. We grew up having everything; maybe our parents had two cars. And now, with the current generation, there's a trend toward shared economies," said Michael Fischer, a spokesman for DriveNow in Germany. As a car manufacturer, do you want to lose this group? Or offer them something? Because, apparently, you cannot sell to them. Car2Go, which uses fleets of Daimler's Smart cars, pioneered the one-way model with a pilot project in Ulm, Germany, in 2009. More and more, people in cities don't want their own cars. But in many ways, car sharing was unattractive," said Andreas Leo, a spokesman for Car2Go in Europe. It was hard to reach, you had to book in advance, you had to pay a monthly fee whether you used the car or not. We looked at the technology and decided to develop car sharing without these restrictions. Now in 21 cities, Car2Go puts its worldwide membership at 400,000. Berlin, with 1,200 cars, has the company's largest fleet. DriveNow, whose fleet is made up of Minis and other BMWs, is active in four German cities with 700 cars in Berlin. It doesn't cost much to join; the idea is that a short trip should cost less than a taxi. DriveNow costs about $39 to register and 32 to 46 cents a minute to drive. The Car2Go registration fee is about $27 and 39 cents a minute to drive. One-way car sharers tend to be about 30 years old, male and technophiles. Both Car2Go and DriveNow, however, report that the longer they are in a city, the more women and older people join. "It is a new kind of mobility, a new stage of mobility, especially for young people," said Christoph Menzel, a professor with the Institute for Traffic Management at the Ostfalia University of Applied Sciences.