The report discusses ways to protect metal structures on highways, like guardrails and bridge girders, from corrosion. By using galvanizing instead of paint, the materials can be protected for longer periods. Different materials like aluminum-alloy and concrete were tested, but unpainted low alloy steel was found to be the best for bridge girders. The Department also tested various paint systems for bridge girders and made specification revisions based on the results. Overall, using galvanizing and unpainted low alloy steel can help extend the lifespan of highway metal structures.