Motorists are facing nightmare journeys over the bridge

The first of this year's traffic restrictions starts in the early hours of Saturday morning.

Strain on the bridge means that checks, maintenance and repairs are now needed regularly although officials stress safety is not at risk.

Planners have avoided the peak tourist months of July and August for the work.

However, closures are due to be imposed on selected weekends until November.

During April, May and the beginning of June the bridge will be reduced to one carriageway at the weekends.

Night-time closures

It will also be closed completely for three hours in the middle of the night on Tuesday and Thursday nights in May and June.

The bridge, which was built 40 years ago, carries more than 20 million vehicles per year, twice the number it was designed for.

The Forth Estuary Transport Authority (Feta) said it hoped to keep traffic disruption to a minimum.

Sections of the support cables are being examined, meaning lanes have to be shut to avoid hazards and to allow access for maintenance teams.

An acoustic monitoring system will be installed on high cables to listen for faults, following an assessment of low level cables.

The �10m programme also involves painting the south tower and the installation of new electronic pay barriers.

A canopy will be erected over the south tower during painting at high levels.