The first car-share lane on a British motorway has been given the green light, but the concept of car sharing to save money, time and fuel has been accepted by motorists overseas for years as well as by people using specific schemes.
Going my way?
The new £2.5m lane on a busy route between Bradford and Leeds will aim to give faster rush hour journeys to cars with more than one occupant.
It opens in 2007, followed by a second car-share lane on the M1 a year later - work on which has already started.
The government announced plans for a pilot High Occupancy Vehicle (HOV) lane in December, 2004, as part of its moves to tackle congestion and encourage car-sharing - which a National Audit Office report pointed out was already successful overseas.
Up to three million people a day in the US use HOV lanes to commute into cities such as Washington and Los Angeles.
Transport Secretary Alistair Darling told BBC's Five Live the system worked well overseas.
"This has been tried, not just in America, but in Australia, in Canada, and other countries as well, so we do have experience and that's why I think we should try it in this country," he said.
"I think it's one of a range of measures that we need to introduce, because frankly, in 20 or 30 years' time, we'll face absolute gridlock unless we're prepared to take sometimes difficult, sometimes unpopular decisions, but to my mind a sensible measure."
Around 18 months ago, the Department of Transport launched a Good Practice Guide to "making car-sharing and car clubs work".
It said car sharing could be done formally - via an organised scheme, or informally via an arrangement between family, friends or work colleagues.
The department suggested benefits included reducing parking problems, environmental benefits and saving money.
"A more sociable commute" and security benefits in the event of a breakdown were among the less obvious advantages it gave.
Slugging to work
In parts of the US the car sharing concept has gone a step further with "slugging".
Visitors to the US capital can see groups of people dressed for the office waiting at specific points to thumb a lift with a stranger.
Washington's slugging phenomenon began more than 30 years ago with the start of HOV lanes. Casual car-pooling began as solo drivers picked up passengers from bus stops so they could have a swifter trip to work.
In Washington commuters wait for cars going their way
It led to the development of set pick-up and drop-off points, as well as to accepted etiquette and rules for both drivers and passengers.
The "slugs", or potential passengers, can decline a ride if they get a bad feeling about the driver.
It is understood the term "slugging" came from bus drivers who try to work out if people at their stop were genuine passengers or just people looking for a free lift - in the same way they looked for fake coins or "slugs".
The internet has also become as a way for people to find lifts, either casually or via schemes putting together passengers and drivers.
Backpackers looking for ways to travel cheaply across Australia's wide land masses have for years scanned notice boards to share lifts, and this has now advanced to specific websites.
Meanwhile, in Cuba, a lack of car owners has led to informal car-sharing and people in rural areas wait by the roadside to hitch-hike into town or even for the daily commute.
In the UK, lift-sharing has already become the norm for thousands of commuters. Liftshare, set up in 1997, claims around 104,000 members on its books and says it now sees around 250 people a day joining.
Liftshare's Managing Director Ali Clabburn said the "social enterprise", run mainly on the internet, encouraged motorists to offer and take lifts.
It aids car-sharing among a wide range of organisations from schools to local authorities and runs schemes for companies, including BT and Cable and Wireless.
Mr Clabburn said people usually shared lifts during their leisure time, when the average car had 2.2 occupants, but this went down to around 1.2 occupants for the commute.
"It is a big difference, and we want to change the way people think about car sharing to work. We think this country already has enough roads, and these roads are congested with cars carrying an estimated 38 million empty seats every day," he said.
The HOV lanes have their critics, who say the system leads to unused road space, is expensive and open to abuse.
Motoring journalist Quentin Wilson told Five Live: "It's just not a cure for congestion."
"You go to LA and you drive down the freeways and there aren't that many cars in the high-occupancy lanes, it's as simple as this," he said.
"Then you've got the issues of who polices them. We certainly haven't got the police cars to monitor them here in the UK, which means we're going to have more cameras, which is going to really, really get people cross."
Paul Watters, from the AA Motoring Trust, told BBC's Radio Four's Today programme the idea behind the HOV lanes was good, but that it may not work in practice.
"Across the UK motorway network, I'm not so sure that this would be an efficient use of the road space because it just isn't practical in many instances to car-share," he said.