Summary: GAO discussed the Department of Transportation's (DOT) efforts to develop a National Highway System (NHS). GAO noted that: (1) although DOT has articulated many goals for NHS, it needs to establish and link these goals to system preservation, maintenance, and performance expectations to form a solid system foundation; (2) a well-maintained system foundation should enable the system to achieve its other goals including economic development, enhanced mobility, improved air quality, and the promotion of travel and tourism; (3) all of the 10 states reviewed have requested adjustments to the NHS mileage originally allocated to them; (4) although 6 of the 10 states requested increases in their mileage adjustments assuming that more NHS miles would increase federal funding in the future, DOT does not plan to link NHS designation with funding; (5) DOT does not plan to establish NHS connections with other transportation modes until 1997; (6) although DOT has developed a map that identifies possible connection facilities, the map does not reflect the actual or proposed NHS connection sites; (7) congressional approval of NHS may be premature, since DOT has not clearly identified NHS connection facilities; and (8) DOT needs to develop a strategy that will respond to demographic and economic changes and address how NHS will expand, what rationale will be required to support size adjustments, and how frequently adjustments will need to be made.