The Pontchartrain Causeway Bridge is recorded in the Guinness Book of World Records as the longest over-water highway in the world. The 24 mile long bridge is a vital link connecting Metairie and Mandeville, Louisiana for commuters who work in the Central Business District of New Orleans. 

The Causeway has boosted the fortunes of North Shore communities by reducing the drive time into the New Orleans metropolitan area by over 50 minutes. HDG was specified on the project for its corrosion protection necessary in the harsh brackish water of Lake Ponchatrain which surrounds the bridge and the message board. Maintenance on the structure is very difficult to perform since traffic runs 24/7. HDG means little or no repair work would be necessary on the structure. 

The steel structure is protected by HDG which was suggested by the Corp of Engineers and used previously on six other bridges and highway spans in Louisiana. The specifier acknowledged ASTM A123 was easy, reliable and cost effective both initially and considering the 35 year life-cycle cost.