Model Inventory of Roadway Elements – MIRE, Version 1.0

67. Roadside Rating

Definition: A rating of the safety of the roadside, ranked on a seven-point categorical scale from 1 (best) to 7 (worst).

Attributes:

• Rating = 1
  • Wide clear zones greater than or equal to 30 ft from the pavement edgeline.
  • Sideslope flatter than 1:4.
  • Recoverable.
• Rating = 2
  • Clear zone between 20 and 25 ft from pavement edgeline.
  • Sideslope about 1:4.
  • Recoverable.
• Rating = 3
  • Clear zone about 10 ft from pavement edgeline.
  • Sideslope about 1:3 or 1:4.
  • Rough roadside surface.
  • Marginally recoverable.
• Rating = 4
  • Clear zone between 5 to 10 ft from pavement edgeline.
  • Sideslope about 1:3 or 1:4.
  • May have guardrail (5 to 6.5 ft from pavement edgeline).
  • May have exposed trees, poles, or other objects (about 10 ft from pavement edgeline).
  • Marginally forgiving, but increased chance of a reportable roadside collision.
• Rating = 5
  • Clear zone between 5 to 10 ft from pavement edgeline.
  • Sideslope about 1:3.
  • May have guardrail (0 to 5 ft from pavement edgeline).
  • May have rigid obstacles or embankment within 6.5 to 10 ft of pavement edgeline.
  • Virtually non-recoverable.
• Rating = 6
  • Clear zone less than or equal to 5 ft.
  • Sideslope about 1:2.
  • No guardrail.
  • Exposed rigid obstacles within 0 to 6.5 ft of the pavement edgeline.
  • Non-recoverable.
• Rating = 7
  • Clear zone less than or equal to 5 ft.
  • Sideslope 1:2 or steeper.
  • Cliff or vertical rock cut.
  • No guardrail.
  • Non-recoverable with high likelihood of severe injuries from roadside collision.

See Figure 4 for additional detail.

Priority: Critical Alternative

HPMS/Tool Requirements: HSM/IHSDM (Required)

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Figure 4. Illustration of Roadside Ratings.

Source: Zegeer, C.V., J. Hummer; D. Reinfurt; L. Herf; and W. Hunter (1986). Safety Effects of Cross-Section Design for Two-Lane Roads, FHWA-RD-87-008, Federal Highway Administration, Washington, DC.