Since promulgation of the Federal Noise Regulation in 1970, State Departments of Transportation (DOTs) have constructed over 2,200 miles of noise barriers at a cost of more than $3 billion dollars using Federal-aid funds. The FHWA has promoted flexibility for DOTs to design their noise programs based on cost, public desire, and other environmental considerations. Noise barriers can be made from many material types, such as concrete, block, brick, wood, metal, and plastics. The number of viable materials has increased substantially over the past 36 years. The objective of this project was to develop guidelines for the selection and approval of noise barrier types and materials.