Evaluation of a smartphone roughness meter

Abstract

Paper presented at the 33rd Annual Southern African Transport Conference 7-10 July 2014 "Leading Transport into the Future", CSIR International Convention Centre, Pretoria, South Africa.

The remoteness of the Pacific Island Countries (PICs), similar to parts of Africa, creates difficulties, both logistically and economically, to undertake detailed in-country investigations on the road networks. Therefore, rapid assessments of the condition of the existing road pavements are required to determine the level of required donor investments to maintain the integrity of the road network. This paper explores the use of Roadroid, a simple android application, as a low cost solution to evaluating road roughness in the Pacific region. The case study presented in this paper demonstrates the use of the Roadroid application on the road network in Kiribati, one of the smaller and debatably the most remote PIC. The results from the study discuss the performance and practicability of the android application, primarily as an Information Quality Level-3/4 information device, in the Pacific region. The results from the field surveys supported the delivery of an Information Quality Level- 3/4 device. The large variation reported in the surveys between the International Roughness Index collected was attributed to the small sampling intervals embedded in the device. Post-processing of the data, which averaged the unfiltered data across one kilometre sub-sections along the main road in South Tarawa, reduced the variability reported across the road network and provided results consistent with what experienced evaluators expected. Field surveys were conducted with the smartphone device and the data was analysed post survey. However, the statistical reliability of the device was less satisfactory when the roughness measurements were compared across various speeds. However, within the accuracy limits of an Information Quality Level-3/4 device, considered to be ±20 % of the International Roughness Index, the equipment more than satisfied the need. Roadroid can assist the asset management of road networks by offering a low-cost solution to monitoring and reporting on the roughness condition of pavements in the Pacific region, as well as in other developing regions. Although this paper reports on the performance of the device, further comparison is recommended to confirm the reported International Roughness Index values accurately reflect the condition of the road pavement. To do so, it is recommended to comparatively study the results from the Roadroid android application with those from specialized instrumented vehicles, such as a laser profilometer.