Road condition evaluation using the vibration response of ordinary vehicles and synchronously recorded movies

Abstract

Frequent and quantitative assessment of road condition is important as the maintenance of the road infrastructure needs to be performed with a limited budget. Vehicle Intelligent Monitoring System (VIMS) has been developed to estimate an index of road ride comfort (International Roughness Index; IRI) by obtaining the acceleration responses of ordinary vehicles together with GPS position data. VIMS converts the vertical acceleration of the measurement vehicle to acceleration RMS of the sprung mass of the standard Quarter Car model, and then to IRI using an approximate expression. By driving over a hump of a known profile and comparing the responses with Quarter Car simulation responses, a variety of vehicles can be calibrated; a non-linear quarter car model equivalent to the vehicle is identified. By performing numerical simulation using the nonlinear vehicle model, the difference in driving speed can also be calibrated. The measurement results can be exported to maps to comprehend road condition in a geographical view and to other data base systems. In addition, smartphones which can record motions, GPS data, and movies synchronously are utilized to improve VIMS. Because practical installation locations of smartphones are limited and because angular velocity responses are less subjective to difference in installation locations, VIMS is extended to utilize the pitching angular velocity. Furthermore, high frequency components of acceleration responses are analyzed to distinguish local pavement damages or joints from rough road sections. The examination of synchronously recorded movies confirmed the capability to distinguish the local conditions.