A Transport Scotland report favoured a cable-stay bridge

The 43-year-old bridge, which connects Edinburgh and Fife, has been badly affected by corrosion and may have to close to heavy vehicles in 2013.

The plans for a replacement bridge or tunnel at South Queensferry - to the west of the existing 2,512m (8,242ft) bridge - will be shown at 12 venues.

Ministers are to make an announcement on the final choice later in the year.

They will consider feedback from the public alongside technical details.

The choice of replacement crossing has been a subject of fierce debate.

'Better option'

Corrosion is a major problem for the current bridge across the Forth, and the Forth Estuary Transport Authority (Feta), which is responsible for the bridge, has warned it would have to be closed to heavy vehicles by 2013.

The Scottish Government agency overseeing the bridge project, Transport Scotland, favours a bridge replacement rather than a tunnel crossing.

A report conducted by Transport Scotland also found a cable-stay bridge rather than a suspension bridge to be a better option.

Exhibitions are being held at Edinburgh's Roxburghe Hotel and Queensferry Hotel in North Queensferry until 24 August.

A replacement suspension bridge is also proposed

A number of other locations in Fife, Tayside and the Lothians will be visited over the next few weeks.

Meanwhile, the latest transport statistics and a study commissioned to look at the impact of removing tolls from the Forth and Tay bridges suggest an increase in the number of car journeys on Scotland's roads network over future years.

On Monday two Scottish Government reports were completed, Main Transport Trends 2007 and the Toll Impact Study.

The reports showed a 3% increase in traffic volume last year and concluded that removing tolls would increase congestion.

Type of crossing

Finance Secretary John Swinney said: "The Forth replacement crossing will be one of the biggest infrastructure investments ever seen in this country.

"It is vital to Scotland's future, and with such an important decision I am very keen to hear people's views on the proposals.

"But if we are to keep Scotland moving in years to come, and achieve our aim of improving economic growth, it is clear that we need the public to help us on more than just the decision on the type of crossing.

"Monday's reports show that we face growing traffic levels on our roads."