The 50th anniversary of the Silver Jubilee bridge linking Widnes and Runcorn is being celebrated.
About 200 classic cars gathered at Heath Park, Runcorn, at 1000 BST before travelling in convoy over the bridge to Victoria Park in Widnes at midday.
Some of the vehicles, which are from the past 50 years, would have been new when the bridge opened in 1961.
They will then be on show in the park all afternoon. Army parachute display team the Red Devils will also drop in.
The team will land there between 1300 and 1700 BST.
Other celebrations planned include a funfair and falconry display.
Drivers are being warned to expect traffic disruption in and around Heath Park, Runcorn, Victoria Park, Widnes and along the convoy route at about 1200 BST.
The bridge, which crosses the River Mersey, was built as a replacement for the 1901 Transporter Bridge.
Halton Borough Council leader Rob Polhill said: "This unique procession will allow Halton's residents to line the streets and celebrate 50 years of the iconic link that unites our two towns."