Although London is the worst region, the federation says that the problem extends to many other parts of the country. The A556 in Cheshire, the M61/M63 in the North-west, the A38M in Birmingham and the Leeds inner- city ring-road are also picked out for criticism.
The federation's criticisms are included in a report called "Signing: the case for investment". It says good signing contributes towards reduced speeds, reduced congestion and fewer accidents. Mark Glover, the report's author, says the cost of poor singing is estimated at pounds 35m a year in London alone.
The costs include lorries getting lost, businesspeople arriving late for meetings and a higher rate of accidents.
The report has won the backing of the Royal Automobile Club. Kevin Delaney, the RAC's traffic and road-safety manager said: "The lack of investment in signing is not only short-sighted. It is a national disgrace. Good signing is a highly cost-effective means of improving road safety and reducing congestion and pollution."
The report criticises the Government's decision to postpone the London Resigning Project, which was due to start earlier this year at a cost of pounds 17.6m.
It was postponed due to lack of funds. The federation says the programme should be reinstated in the next financial year. It calls for the Government to release funds to local authorities to implement minor works and local safety schemes. It also advises the Government to take advantage of more modern materials which improve the "reflectability" of road signs, making them easier to see, especially at night.
"Road signing in London is appalling," the british Road Federation's Mark Glover said. "The signs at the Elephant and Castle, for example, one of London's busiest junctions, are in a terrible state." Mr Glover said that almost every sign at the roundabout, in south London, was of poor quality. Some were out of date, illegible or in permanent darkness. Others were rendered useless by peeling paint or were covered in graffiti.Reuse content