On national roadways, blue signs indicate rest areas, service stations, hotels, eateries and the availability of telephones. Blue signs are also used to denote areas for parking by disabled travelers.
Along the highways, signs bearing the name of the state may appear on a blue background with white lettering. Red, white and blue signs denote interstate highways.
Local jurisdictions may have flexibility with regard to street sign color. Peggy Jensen, a columnist for The Herald Independent in Cottage Grove, Wis., explained in 2009 that blue street signs were chosen by the town's highway superintendent for increased visibility as a contrast to the area's green foliage.
In Barrows County, Georgia, blue street sign numbers were sold to residents to help the county emergency services department personnel more quickly find residents in need of assistance.
