Pursuant to a congressional request, GAO reviewed federally funded highway preservation efforts in seven states to determine the effects of allowing states to develop their own geometric design standards for highway resurfacing, restoration, and rehabilitation (3R) projects. The Federal Highway Administration (FHwA) allows states to adopt their own geometric design standards for 3R projects, rather than use standards for new construction. GAO found that exceptions to design standards had been granted for 43 percent of the 3R projects examined in six states; the most common exceptions were to standards for vertical curves and shoulder widths. The safety effects of such exceptions are not known and further data are necessary to determine the effects. Some states were using standards for new construction developed by FHwA and the American Association of State Highway and Transportation officials, some were using state standards for new construction, and others were using standards for 3R projects developed in conjunction with FHwA division offices. GAO found that the extent of information used by states to justify exceptions for substandard features varied widely. Neither FHwA nor the states have reviewed the safety effects of specific exceptions to design standards; FHwA and state officials said that studying the effects of exceptions is difficult because of the lack of accident data for 3R projects. The Department of Transportation is now required by law to study the safety effectiveness of current design standards to determine the most appropriate standards to apply to 3R projects. GAO found that not all FHwA divisions make routine site visits before approving exceptions to design standards and believes that FHwA divisions that make such site visits are better able to analyze the safety aspects of 3R projects than those that do not.