By Tom Symonds
BBC transport correspondent
Road charging is the government's radical proposal to cut congestion. Here are the results of a BBC experiment to find out what it would be like.
KAREN CROSS - SCHOOL RUN MUM
Final Bill: £86.49
Miles Travelled: 754
Cheapest day: 13p
Potential annual bill: £1,032
On many days Karen runs her daughter Vicky and son Nathan to their school and nursery - though not every day as she shares the task with other parents and she gives Vicky's two friends a lift too.
At the moment she thinks her children are too young to take the bus. But our research revealed that Karen actually uses her car for more journeys than the school run.
She uses her car to visits friends, do the shopping, and visits connected with her fledgling children's clothing business.
Karen was shocked at the size of her "bill".
She said she couldn't afford it on top of all the other expenses associated with bringing up a family.
But when it encouraged her to bring Vicky home from school by bus, the bus was packed by boisterous school children.
They jostled all the way and had to stand.
Luckily for now the problem resolves itself. Next year Vicky will be old enough to go to school on her own.
MARGARET WALSH - THE FLORIST
Final Bill: £27.89
Miles Travelled: 1,056
Most expensive day: £2.38
Cheapest day: 7p
Potential annual bill: £324
Margaret delivers flowers throughout Staffordshire and into neighbouring Derbyshire to places like Alton Towers and the local JCB factory in Uttoxeter.
In principle she's against road charging but she was delighted with her low bill.
She conceded that if the money was spent on environmentally friendly schemes, she might have second thoughts about her opposition to road charging.
Her charges were low because she uses country roads.
Rural motorists who need their cars may be pleasantly surprised by how much cheaper their charges are compared to those in cities.
Importantly for Margaret, the government could decide to reduce motoring and fuel taxes to compensate for road charging.
If this were the case, we found that Margaret would actually be better off than she is now. In fact, under Professor Galister's model she would pay £36.79p a month less in motoring taxes.
NICK WADDINGTON - THE COMMUTER
Final Bill: £126.77
Miles Travelled: 1,588
Most expensive day: £13.96
Cheapest day: 79p
Potential annual bill: £1,512
When chartered surveyor Nick Waddington moved from London to rural Worcester so that his wife and children might enjoy the advantages of country living, he realised he would have to undergo a long 32-mile daily commute into Birmingham.
He also uses his car to make site inspections in Birmingham which are not usually on bus routes as he specialises in commercial property.
Nick's daily commute accounts for £6 of his road bill.
The lanes around his home attract a charge of 2p a mile, rising to 5p on busy rural A roads. As he nears Birmingham on the M5 charges shoot up to 32p a mile.
Even though Nick's charges are the second highest, he was pleasantly surprised with his monthly road charging "bill".
He takes the view that if the roads were less congested, he might be able to save 20 minutes on each leg of his commute which would give him more time with his family.
He said he would be happy to pay the £6 charge for this himself.
He also felt that less congested roads would mean that when at work he would spend less time getting to appointments which would be more efficient and his employers would be liable to pay this element of the road charges.
But he still wasn't tempted by the train, which he said, was more expensive because of having to get a taxi to the station, was less comfortable, and took longer.
STEVE COAPE-ARNOLD - WHITE VAN MAN
Final Month Bill: £194.31
Miles Travelled: 3,313
Most expensive day: £21.11
Cheapest day: £1.19
Potential annual bill: £2,338
Steve has a white van delivery business.
He was dismayed at his monthly road charging "bill" - which is the highest of all four motorists.
His white van was barely off the road with house clearances and the delivery of kitchen units and shop fittings forming the core of his business.
Most of his journeys are around the Midlands but he has to make his deliveries when it is convenient for his customers.
He can't chose to make them when the road charges might be lower.
His worst charges came when he had a delivery to Winchester and the direct route took him on busy A roads which carry a high charge.
He says he would have no choice but to put up prices to his customers if road charging was introduced.
Needless to say he's very much against road charging.