Interpreting road surface condition scores

The road surface condition score represents the overall condition of the surface. A score of 100 % represents the best possible condition and 0 % the worst.

A deduct value is calculated for various road surface distress types using their extent values. The extent value of a distress is defined by its lateral extent (width relative to the road width).

Figure 1. Distress extent to deduct value mappings for all distress types considered in the calculation of the road surface condition score

Each distress type has their own severity value and deduct mapping.

Figure 2. Distress severity to deduct value mappings for all distress types considered in the calculation of the road surface condition score

The road surface condition score is calculated by subtracting the deduct values from the value 100 %.

For example, a video frame shows two kinds of distresses present: binder bleeding and potholes. The relative lateral extents of the binder bleeding and potholes are 40 % and 10%, respectively. As shown in the figure above, the respective deduct values are determined as 20 % and 40 %. For this frame, the overall pavement condition is 100 % − (20 % + 40 %) = 40 %.

The road condition class is based on the condition score. By default, a score of 0‑20 % results in class 1, 21‑40 % in class 2, 41‑60 % in class 3, 61‑80 % in class 4, and 81‑100 % in class 5.