Document Type

Technical Report

Publication Date



This project focused on implementing the 3DOBS technology (developed under Phase I and Phase II) for successful detection, quantification, and visualization of concrete bridge deck distress features at near-highway speeds for routine MDOT inspections. The integration and further re-defining of the 3DOBS methods into MDOT practices was accomplished by assessing 11 bridge decks with an average size of 10,350 square feet. Distress features were categorized according to the Bridge Element Inspection Manual and compared to traditional (visual) element level inspection results. The Great Lakes Engineering Group, LLC worked with the research team to inspect, interpret, report results, and advise on current condition state reporting requirements. The project team also trained MDOT bridge inspectors in the use of the remote sensing equipment, data collection, data processing, and reporting through multiple different training sessions. A cost comparison between 3DOBS and traditional inspection methods was conducted, with 3DOBS costing an average of $92 per bridge, as compared to $39 for traditional methods. For producing standard element level condition state tables, 3DOBS cost more than a traditional inspector, but is still estimated to be less than $100 for an average bridge in this study.

Publisher's Statement

This document is available to the public through the Michigan Department of Transportation. Available online here:



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