Which term refers to the evenness of the pavement surface?

• A. Structural Adequacy
• B. Pavement Distress Type
• C. Pavement Smoothness
• D. Pavement Distress Amount

Answer: (C)

Understanding pavement smoothness is about how even the surface is from wheel path to wheel path and along the direction of travel. This evenness directly affects ride quality, vehicle wear, and safety, because a very rough surface can cause vibrations and instability even if there aren’t visible surface defects.

This concept is different from structural adequacy, which is about whether the road can support expected loads without failing; it is also different from pavement distress type, which describes the kind of surface faults (like cracks or potholes); and from pavement distress amount, which measures how much distress is present but doesn’t necessarily capture how flat or uniform the surface rides.

In practice, smoothness is measured with devices and indices that quantify vertical deviations from a flat plane, such as profilometers or inertial profilers, yielding numbers like roughness indexes. A lower roughness value means a smoother, more even surface; a higher value indicates less evenness.

So, the term that refers to the evenness of the pavement surface is pavement smoothness.