A radical solution to Oxford's traffic congestion - which permits entry to vehicles according to their colour and the time of day - looks likely to be in force within three months.

Under the system, the morning and evening rush hours would be divided into 15-minute periods. During each period only cars of one particular colour - or a tint of that colour - would be allowed access to the city centre's roads.

The idea has won support from a prominent Green city councillor but caused outrage among some city employees, who say they may have to respray their cars or find another job.

The recommendation is in a report by a high-level university think tank, the Traffic Routing Independent Policy Evaluators, based at St Christopher's College, Oxford.

Academics have closely studied a similar scheme in the Chinese city of Wee La Fing where traffic levels have fallen by up to 30 per cent.

A provisional daily timetable gives owners of red cars priority for an extended period from 8am to 8.30am, with 8.30am to 8.45am reserved for silver and white vehicles, then subsequent 15-minute periods for, respectively, blue, green, and 'other' colours up to 9.30am, when the roads will again be open to vehicles of every hue.

A similar timetable will operate from 4.30pm to 6pm.

Red cars will have longer than others because the city and county council pool cars are all that colour.

Buses and taxis would be exempt, while motorcycles would be excluded altogether during colour-controlled periods.

To catch unauthorised cars, colour-sensitive cameras would be placed along Botley Road, Abingdon Road, Banbury Road and Woodstock Road.

Wrongdoers would be photographed and issued with a fine of £60, just as with speed cameras.

Chairman of the think tank, Prof Jose Noway, said: "This one simple measure could transform Oxford from a clogged-up and polluted no-go area to a pleasant - and colour-coordinated - modern metropolis."

Green city councillor Iona Redcarr said: "This is the way ahead for our historic city and its precious environment."

But a spokesman for city centre businesses and schools said: "The scheme is a recipe for chaos - and it discriminates against the colour blind."

An early test of the colour cameras suffered teething problems.

A machine installed in Abingdon Road mistakenly generated fine documents for a road repairman in a bright yellow jacket and a white horse.

"Colours like turquoise are proving a particular problem," said a council engineer. "Is it blue or is it green?

"The machine gets confused."

Officers reported that the machine also malfunctioned on days when darkness fell by 6pm.

But council staff are confident the equipment will work by the time of the anticipated launch on June 31.

The council was expected to approve the new system today, before noon.