The Highway Bridge Report indicates which routes are included in the National Highway System (NHS). The NHS is approximately 160,000 miles (256,000 kilometers) of roadway important to the nation's economy, defense, and mobility. It includes:

• the Interstate Highway System
• routes that provide access to a major port, airport, or other public transportation facility
• routes that provide access between major military installations
• routes that are important to the United States' strategic defense policy