Car-sharing, pioneered in Switzerland in the 1970s, is gaining popularity across the globe as people shy away from the cost of owning and maintaining an automobile in big cities.
And it is proving particularly successful in Germany, where carmakers themselves are keen to get a slice of the action.
In addition to concerns about greenhouse gases and pollution, there are many reasons why a growing number of urban dwellers are opting not to buy their own car: a chronic shortage of parking space, soaring insurance and upkeep costs, and high fuel prices.
Many prefer to use the well developed and efficient public transport systems found in Germany and other countries.
"In towns and cities, young people don't necessarily want to have a car," said Stefan Bratzel, director of the Center for Automotive Management (CAM) in Bergisch-Gladbach.
They still want the convenience of a car, without the financial burden of owning one. Yet they do not want to have to use traditional car-rental firms every time they decide to go for a spontaneous jaunt into the countryside.
For those reasons, car-sharing - which enables renting a car even for very short periods of time, at any hour of the day or night -- appeals to such people.
The scheme has also become handy for businesses which do not want to maintain a costly fleet of company cars for their employees.
- Germany leads the way -
The first car-sharing firm in Germany, Stattauto, was set up in Berlin in 1988, starting out with a single car.
By last year, there were as many as 140 operators in Europe's biggest economy, with 1.04 million registered users and a total combined pool of 15,400 cars at their disposal, according to figures compiled by the car-sharing industry federation BCS.
"That represents approximately half of the total offer in Europe," said Franck Leveque of British consulting firm, Frost & Sullivan.
Car sharing has been slower to catch on in other European countries. In Italy, there are around 250,000 customers, and in France and Britain around 200,000 each.
Further afield, there are around 700,000 users in Japan, which started car-sharing schemes in 2007, and 1.3 million in the United States, according to recent data published by the University of California in Berkeley.
Gunnar Nehrke of BCS said that Germany stands out because of the sheer size and extent of its network.
"In many countries, there is car-sharing in the capital, or two or three of the biggest cities. Here, car-sharing is available in 490 towns and municipalities," he told AFP.
BCS predicts the number of users in Germany will rise to two million in the next five years.
German companies active in the sector include Cambio, Stadtmobil, Book-n-drive, TeilAuto or CiteeCar, all of which have been active for a long time investing not only in major cities, but smaller towns as well.
The south-western city of Karlsruhe has the highest density of shared cars at 2.15 cars for every 1,000 inhabitants.
Leveque at Frost & Sullivan said that another important factor in the success of car-sharing in Germany was the role of the automakers themselves: BMW has its own scheme, called Drivenow, and Daimler launched its Car2go in 2008.
- Fast-growing market -
The global car-sharing market is still small. According to consultancy firm Roland Berger, it is projected to grow by 30 percent each year and reach 5.6 billion euros in 2020 -- a small fraction of the vast 1.3 trillion euro market of global auto sales last year.
But automakers see it as a new marketing channel, a way "of letting customers get to know the brand and possibly buying one later," said Bratzel at CAM.
Berlin has been dubbed by local media as the "world capital of car-sharing."
At the end of 2014, the number of shared cars in the German capital stood at 3,180, which is almost as many as in all of Britain.
As many as 45 percent of households do not own a car in Berlin, where a young, often university-educated and relatively well-off population sees the advantages of car-sharing.
Transport Minister Alexander Dobrindt recently promised to help promote "this new form of mobility" by offering free parking to car-sharing vehicles.