Case studies of public records spanning nearly 60 years have shown that heavy duty asphalt concrete pavements have an outstanding record for good performance and economy on Ohio's Interstate and other major highways. These studies confirm that asphalt pavements properly designed and constructed for heavy truck traffic do not have to be dug up and patched periodically because of structural breakdown. The studies show that only low-cost surface maintenance at 10 to 15 year intervals has been required.