By 2008, a section of the newly-widened M1 will boast the UK's first motorway dedicated car-sharing or High Occupancy Vehicle (HOV) lane. So who can use it? And how will it be enforced?
The government hopes car sharing will cut traffic by 5%
Washington State lays out the ground rules for using its HOV lanes pretty clearly.
"Children and your spouse count as carpool passengers.
"Pets do NOT count as carpool or vanpool passengers."
But with or without Fido, solo drivers continue to take their chances in the US's 125 dedicated lanes.
HOV motorists have been calling the "shop-a-lane-cheat" hotline in droves to report lone drivers sneaking into their lanes.
Whether there is any truth in the story of the pregnant woman arguing that her unborn child was her second person is uncertain.
But there are plenty of examples of people dressing up shop dummies in wigs and clothes and sitting them in the passenger seat.
One, caught out after causing a major pile-up in southern California by veering in front of a school bus, told journalists: "This saved 45 minutes on my commute each day."
"There was just this temptation."
In the UK, the Department for Transport hopes the M1 scheme will be "self enforcing" - there will be no special cameras, nor a gated entrance to the HOV lane.
Instead police patrols and the driver's own sense of shame will determine the level of cheating.
No free ticket for pet owners
If drivers are carrying one or more passengers, be they colleagues, friends, hitchhikers or children, theoretically they are free to zip ahead in the HOV lane. But again, pets definitely do not count.
"We are looking at vehicles carrying two or more people - it doesn't matter who," said a Department for Transport spokeswoman.
In the States, complete strangers have been queuing up to take advantage of the scheme for more than 20 years.
"Slugging" - or casual carpooling - sees people lining up at the side of the road for a free lift from lone drivers who can then legitimately dodge the jams in an HOV lane.
Car sharing schemes - often run through websites - in which people can register their details to find someone with a matching journey have already seen some success in the UK.
'Slugs' queue up for a free lift to work in Springfield, Virginia
Liftshare has more than 60,000 members on its books and says the estimated distance shared each year by them is 5,525,353 km or 3,433,295 miles.
The government thinks car sharing could lead to a 5% reduction of cars on the road.
And while the exact details have yet to be been ironed out, those caught cheating can expect to face some punishment - possibly a fine.
But is the government worried about drivers dressing up pets and shop dummies to cheat their way into the lane?
"We would expect enforcement techniques to be sufficient to deal with mischief makers," said the spokeswoman.