Distress Identification Manual

The official mobile companion to the LTPP Distress Identification Manual (DIM) now fully updated to the 6th Edition, published July 2025.

Used by pavement raters and reviewers nationwide, the DIM provides a consistent, uniform basis for collecting and reviewing pavement distress data. This 6th Edition incorporates the latest LTPP directives and considerations tied to FHWA's Moving Ahead for Progress in the 21st Century Act (MAP-21).

What's inside:

Complete distress definitions, descriptions, and illustrations for all three pavement types: asphalt concrete-surfaced, jointed Portland cement concrete (PCC), and continuously reinforced PCC.
Color photographs and reference drawings to help identify and assess distress severity.
Methods for measuring distress size and assigning severity levels.
Guidance on conducting field distress surveys, from traffic control setup to crack measurement.
Sample forms for recording and reporting distress data.
Reference material on fault measurement devices.

Whether you're in the field collecting data or in the office performing quality assurance review, the LTPP Distress Identification Manual app gives you the current, authoritative reference in your pocket — no internet connection required once downloaded.