Model Inventory of Roadway Elements – MIRE, Version 1.0

75. Terrain Type

Definition: The basic terrain type for the segment. This is a (less than desirable) surrogate for detailed data on curvature, grade and the nature of the roadside, and would be collected only in the absence of those elements. See roadside descriptors above and alignment elements below.

Attributes:

• Mountainous — Any combination of grades and horizontal or vertical alignment that causes heavy vehicles to operate at crawl speeds for significant distances or at frequent intervals.
• Rolling — Any combination of grades and horizontal or vertical alignment that causes heavy vehicles to reduce their speeds substantially below those of passenger cars but that does not cause heavy vehicles to operate at crawl speeds for any significant length of time.
• Level — Any combination of grades and horizontal or vertical alignment that permits heavy vehicles to maintain the same speed as passenger cars; this generally includes short grades of no more than 2 percent.

Priority: Critical Alternative

HPMS/Tool Requirements: HPMS (Sample), SafetyAnalyst (Optional)