The passenger’s comfort depends on vibration of different parts in their body. There are different studies simulating and experimenting vehicle structure and passengers in order to evaluate, measure, control and describe vehicle’s vibration level and its impact on passengers. The purpose is to create technologies that help making vibration frequencies of human organs suitable to that comfort. Low frequencies from minuscule one to 100 Hz, which passengers can feel, are usually caused by suspension system. High vibration frequencies are: oscillation of body and transmission system, contact of tires with road surface, engine’s noise. Usually, vibration of low frequencies, which dominates the spectrum, negatively effects passengers. This paper presents research method uses model 1/4 oscillation of County Bus of 29 seats. Newton method is used to form mathematic equation of the model. Simulating tool is from Matlab Simulink. The result of simulation of the three cases all received the values of vibration acceleration and motion vertical amplitude at the floor, seat, buttocks, chest, abdomen and head of the passenger while sitting on the seat to compare with the value. From average square values of RMS of ISO-2613 standard of acceleration, we have values of vibration acceleration and vertical moving amplitude at floor, seat, rump, foot, chest, abdomen and head of passengers while traveling in bumpy roads.