Gravel road deterioration leads to the disintegration of gravel, resulting in road irregularities such as potholes, rutting and corrugation. The vehicle vibration response to these irregularities on the road surface contributes to the road roughness perceived by gravel road users in terms of ride quality (comfort or discomfort). Therefore, it is crucial to maintain gravel roads at an acceptable level of service for improved ride quality and efficient and safe transportation. In particular, corrugations are a safety hazard that causes discomfort to road users and can also cause loss of control of the vehicle, especially at high speeds and when loose gravel surrounds the corrugations. This paper investigates the contribution of corrugations to the mean square value of the squared magnitude of vehicle vibration response and also the interaction between the vehicle speed and the magnitude of the vehicle vibration response. The mean square values of the vehicle vibration response signals are estimated using a moving average low-pass filter, and the signals are split into adjacent frequency sub-bands with the aid of band-pass filters defined based on the Discrete Fourier transform (DFT). The results of the estimated mean square values of the vibration responses and the band-pass filtered vibration responses reveal that corrugations have a more pronounced impact on the magnitude of the mean values of the squared vehicle vibration response than potholes and would thus significantly contribute to the roughness of gravel roads and the perceived ride quality. A positive correlation between vehicle speed and the magnitude of vibration response to gravel road irregularities was also observed, i.e., increasing driving speed resulted in higher vibration magnitudes. These findings show the potential of the study approach for gravel road condition assessment.