|Location Map ( geo)
|1836, 1898, 1987
The current Bonhill Bridge is the last in a line of crossings at this point, which in the past carried the A82, but is now unclassified. The first bridge was built in 1836 and was a light weight suspension bridge with a single span between stone arched abutments on the river bank. The bridge was often referred to as the 'Bawbee Bridge' as the Scottish term for a half penny - the price of the toll - was Bawbee.
The bridge was replaced in 1898, three years after the tolls were removed, by a steel arch truss bridge, which carried the road and tramways over the river. The bridge span had been widened to eradicate the need for the arched abutments, and these were replaced with solid stone abutments taking the loads from the arch. The bridge was substantially refurbished in 1962, but this could not ensure its future, and a few years later traffic lights and a 14 tonne weight limit were installed. This was probably in 1970, when the A82 was re-routed over the new Dumbarton Bypass Bridge.
The current bridge was opened to traffic in 1987, having been built alongside its predecessor, which was subsequently removed due to the cost of keeping it safe. It echoes the shape of the older bridge, being a steel arch structure very similar to Bonar Bridge in the Highlands. The arch is, however, substantially higher than the older bridge, and tied at the top. Despite the roadway being stronger and wider than before, it seems likely that this bridge carries a lot less traffic than the older bridge did.