Accuracy Analysis of International Roughness Index (IRI) Measurement Using Smartphone Applications Under Varying Conditions

Abstract

The International Roughness Index (IRI) is an index used to assess road conditions It serves as an indicator of road level of service and aids in maintenance planning for the agencies. Measurement techniques vary based on the precision of equipment and calculation methods. High-precision tools, categorized under Information Quality Level (iQL) 1 to 3, include Laser Profilometers that directly measure road surface height variations. Alternatively, lower-cost systems, such as Response-type Road Roughness Measuring Systems (RTRRMS), utilize vehicle-based vibration measurements, including Bump Integrators and Accelerometer-Based Systems. Modern smartphones are equipped with built-in accelerometers, enabling the development of mobile applications for IRI measurement. These applications, such as Total Pave, Road Bounce, Roadroid, RoadLab Pro, Road Bump, and DRIMS, have gained popularity due to their low cost and ease of use. However, measurement accuracy depends on various factors, including the type of vehicle, installation method, and driving speed, as specified by the application developers.

This study focuses on testing and analyzing the accuracy of IRI measurements using smartphone applications under different conditions, including vehicle types and varying speeds, both within and outside developer-recommended guidelines. The objective is to evaluate the differences in measured values under actual conditions and determine whether smartphone-based measurements can achieve accuracy comparable to iQL-1 under appropriate conditions. The use of smartphone technology in road surface assessment presents a cost-effective and efficient alternative, enhancing the feasibility of road condition analysis and maintenance planning in the future.