In this section, the quarter-car model is used to study the response of the vehicle to random
road inputs. First, a linear two-degree-of-freedom car model is reviewed. Then, the response of the
vehicle to random road disturbances is analyzed by treating them either as white noise velocity
inputs or colored noise inputs. It is recognized that the quarter-car representation is too simple for
performing a comprehensive analysis of the ride motions of the vehicle. However, even with this
simplified representation, significant insight into the problem can be gained without greatly
complicating the analysis.