From production to market, most agricultural products are transported by truck. During distribution, fruits and vegetables are subjected to different vibration levels from transport vehicles that vary in frequency and acceleration. Vibration may have a significant effect on the rate of product damages. Vibration levels that occur during transportation depend on many factors, such as: suspension type, traveling speed, road conditions, and features of the packaging. The objective of this study was to determine and analyze the vibration that occurs during truck transport as a function of truck suspension system, vehicle speed and road surface conditions. In this research vibration levels were measured using two types of trucks that are used to transport agricultural produce (one with leaf-spring suspension and the other with air-ride suspension), in three different road surfaces (asphalted highway, secondary asphalt road, and dirt road). Data were analyzed using power spectral density (PSD). The results illustrated that vertical vibration intensity was higher compared with the lateral and longitudinal directions. Statistical analyses using ANOVA test represented the intended factors such as suspension system, traveling speed and road significantly affected PSD values (average PSD in the range of 0.1e5 Hz and peak PSD). In Iran, trucks with leaf-spring suspension generated higher vibration levels compared with the airride suspension one and the measurements of vertical vibration levels were severe in both two truck types compared with ASTM standard.
