National Highway System
The National Highway System (NHS) consists of the most important routes for commerce and trade in the United States and includes the Interstate System and the Strategic Highway Network (STRAHNET), as well as critical intermodal connectors to passenger and freight facilities. The NHS includes 84.0 percent of rural other principal arterials and 87.1 percent of urban other freeways and expressways. Only 4.1 percent of the Nation's total road mileage is on the NHS, but it carries 44.4 percent of the total VMT.
In 2002, 93.7 percent of NHS route miles had acceptable ride quality, while 90.6 of VMT on the NHS was on pavements classified as acceptable. Since 1997, the percent of rural NHS route miles with acceptable ride quality has risen from 94.5 percent to 97.1 percent. The comparable percentages for the urban NHS have remained relatively flat, rising from 83.9 to 84.1 percent.
Between 2000 and 2002, daily vehicle miles traveled per lane mile grew by 3.0 percent on the rural NHS and 2.1 percent on the urban NHS.
The 114,587 structures on the NHS constitute 19.4 percent of all bridges in terms of numbers, but carry 71.0 percent of the total daily traffic volume serviced by the total bridge inventory. Of the total NHS bridges, 23.0 percent were deficient in 2002.
Rural NHS average ride quality could be maintained at 2002 levels at a sustained funding level of $6.33 billion annually. For the urban NHS, this would be between $12.82 and $13.42 billion annually. An average annual investment in bridge preservation of $3.79 billion would be needed so the NHS bridge investment backlog would not increase.
On the urban portion of the NHS, current funding levels for preservation and expansion can be expected to provide improved pavement quality, but a loss in overall operational performance.