In response to a congressional request, GAO provided information on research efforts to develop highway technologies, including cost-effective ways to maintain and rehabilitate interstate highways. GAO found that: (1) U.S. highways have deteriorated rapidly because of a lack of immediate maintenance and rehabilitation; (2) research and technological developments could improve states' abilities to finance highway improvement and rehabilitation; (3) research efforts for highway technology focus on various elements, such as soil, quality of materials used for pavement, traffic loads, and climate; and (4) for fiscal year 1987, states planned to spend about 25 percent of their federal highway funds on research.