PORTLAND — Traffic is busy on the Maine Turnpike as the Memorial Day holiday weekend winds down.

The Maine Turnpike Authority says it expects some 40,000 southbound vehicles to pass through the York toll plaza at the southern end of the highway today as they depart the state.

In all, turnpike officials projected that more than 635,000 vehicles would use the highway from Friday through today.

The Memorial Day weekend marks the unofficial start to Maine’s summer tourist season.