15 March 2001
DISTRESS 53, RUTTING
15.1. Description. A rut is a surface depression in the wheel path. Pavement uplift may occur
along the sides of the rut; however, in many instances ruts are noticeable only after a rainfall,
when the wheel paths are filled with water. Rutting stems from a permanent deformation in any
of the pavement layers or subgrade. It is usually caused by consolidation or lateral movement of
the materials due to traffic loads. Significant rutting can lead to major structural failure of the
pavement. Deduct curves for rutting are shown in Figure 15.1.
15.2. Severity Levels.
Mean Rut Depth Criteria
Table 15.1. Mean Rut Depth Criteria
All Pavement Sections
≤ 1/4 to 1/2 inch (≤ 6.4 to 12.7 millimeters) (Figure 15.2. and Figure 15.3.)
>1/2 inch ≤ 1 inch (>12.7 to ≤ 25.4 millimeters) (Figures 15.4 and 15.5.)
>1 inch (>25.4 millimeters) (Figures 15.6. and 15.7.)
15.3. How to Measure. Rutting is measured in square feet (square meters) of surface area, and
its severity is determined by the depth of the rut. To determine the rut depth, a straightedge
should be laid across the rut and the maximum depth measured.