The efficiency or performance of a roadway vehicle is determined based on its specific performance indices. The ride quality index or ride comfort index is one of the measures of those performance indices. This measure is evaluated based on different standards set by indexing organizations e.g., Sperling ride index, ISO 2631 ride comfort specifications etc. In the present paper, a light-duty four-wheel vehicle system is modelled using Lagrangian method and is subjected to bump and pothole inputs. The vibrational response of the vehicle is evaluated and judged based on Sperling ride comfort specifications.