Highway Performance Classification System - Five Levels

The Highway Performance Classification System is subject to periodic change based on variations in traffic and trade patterns, public input and final acceptance by NDDOT management.

For a larger view click on map below.

Interstate System

Interstates have the highest volumes of annual automobile and truck traffic in the state. Maintaining a high degree of reliability and mobility on these highways is critical in promoting economic activity.

• Travel speeds average sixty-five to seventy-five miles per hour, and traffic is primarily long-distance, interstate, and intrastate.
• These highways have multiple-lanes, full-access control, paved shoulders, load limits are restricted by legal weights, and are very safe.
• The department's goal is to make them free of height restrictions and to provide a good to excellent ride quality.

Interregional System

These highways function similar to an interstate highway. Maintaining a high degree of reliability and mobility on these highways is also critical, since they support economic activity.

• Movements on these highways are primarily long-distance, interstate and intrastate traffic.
• Daytime travel speeds average sixty to seventy miles per hour, with moderate to high volumes of automobile and truck traffic.
• Interregional System highways are either two-lane or multiple lane facilities, may have partially controlled accesses, generally have paved shoulders, and are very safe.
• The department's goal is to make them free of height restrictions, have load limits restricted by legal weights, and are very safe. Limited passing restrictions, and provide a good to excellent ride quality.

State Corridor

Maintaining a moderately high degree of reliability and mobility on these highways is critical, since they support the movement of agricultural commodities, freight, and manufactured products within the state.

• State Corridors also provide connections between lower and higher level roadways. Traffic on these highways is primarily medium-distance intrastate traffic
• Daytime travel speeds average sixty to sixty-five miles per hour, with moderately high volumes of traffic consistent year round, and are safe highways.
• State Corridors are typically two-lane facilities that have segments or locations with partially controlled access, either paved or aggregate shoulders, limited passing zone restrictions, load limits are restricted by legal weights. Bridges and overhead structures provide for the unrestricted movement of legal loads, and the ride is generally good.

District Corridor

Maintaining a moderate degree of reliability and mobility on these highways is desirable. Traffic is primarily short to medium-distance intrastate traffic.

• Daytime travel speeds average fifty-five to sixty-five miles per hour, and are safe highways. They have moderate volumes of traffic relatively consistent year round, with occasional increases in seasonal traffic volumes and truck movements.
• District Corridors are two-lane highways with a good ride quality, and access control is not usually purchased.
• These highways have narrow paved or gravel shoulders, segments with restricted passing zones, 8-ton or 7-ton seasonal load limits.
• Bridge structures provide for the unrestricted movement of legal loads.

District Collector

Maintaining reliability and mobility on these highways is a lower priority, since these highways are generally shorter routes providing connections to the higher road level systems. Traffic is primarily short distance, local, or farm to market.

• Daytime travel speeds average fifty to fifty-five miles per hour with low volumes of traffic year round. However, small increases in truck movements may occur during spring planting and fall harvest periods.
• District Collectors are safe highways that are two-lane facilities with access control usually not purchased, and offer a fair ride quality.
• These highways generally have no shoulders, have restricted passing zones, 7-ton or 6-ton seasonal load limits are normal although some segments may have year round restrictions.
• Bridge structures provide for the movement of typical legal loads, but some structures have load, height, and width restrictions.

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