<div class="htmlview paragraph">The object of this study is to analyse the vehicle ride comfort problem called “FREEWAY HOP” for medium duty trucks.</div> <div class="htmlview paragraph">For appreciating of this phenomenon and its mechanism, vehicle modal testing and hydraulic shaker testing were conducted.</div> <div class="htmlview paragraph">And for checking the various effects of the tuning parameters, computer simulation and the parameter design methods, the well known “TAGUCHI METHOD” were used.</div> <div class="htmlview paragraph">Actual vehicle road testing under the new specifications was conducted to confirm the ride comfort performance.</div> <div class="htmlview paragraph">From these approach ride comfort optimization can be obtained.</div>