IMS Infrastructure Management Services 12/27/2023

City of Everett | RFP No. 2023-057 November 2, 2023 IMS Infrastructure Management Services, LP 16 Rutting and Roughness IMS’ LCMS-2 systems detect rutting on asphalt roadways using laser measurements of transverse profiles that are collected continuously as the RSTs drive at normal traffic speed. With more than 4,000 measurement points collected per transverse profile and sub-millimeter vertical accuracy, the LCMS-2 can define transverse profiles with a high level of precision, accuracy, and repeatability. Once all the transverse profiles are collected for a roadway, IMS determines the rut area and the deepest (or maximum) rut depth for each segment. These values, as well as width of rut and color coding, can be seen in the LCMS-2 laser image to the right. Orange represents high severity rutting, while yellow represents moderate severity rutting. The severities are determined based on maximum rut depth thresholds that are specified in ASTM D6433. Pavement roughness is evaluated by measuring the accumulated difference in the vertical displacement of a road surface, independent of chassis response, over a prescribed road length (longitudinal profile). Roughness is typically reported following the International Roughness Index (IRI) index, which is calculated in real time from continuous longitudinal profile data collected by the RST’s ASTM Class 1 IrisPRO™ pavement profiler. To determine the longitudinal profile, data is simultaneously obtained in compliance with ASTM E950 from three devices: a pulse transducer-based distance-measuring instrument (DMI), high-speed RoLine™ lasers, and an accelerometer. ASTM D6433 Pavement Condition Evaluation During and following the data collection effort, we will evaluate all collected pavement imagery and surface measurements to arrive at Pavement Condition Index (PCI) values. This is a six-step process that includes the following tasks: • RoadInspect™ Pavement Distress Detection – Cracks, rutting, and other pavement distresses are automatically detected in both the 2D and 3D pavement images. IRI values are also calculated at this time. Note: The RoadInspect™ software was developed by Pavemetrics, the firm that manufactures the LCMS-2 technology. • IMS Pavement Distress Classification – Pavement distresses detected by the RoadInspect™ software are then classified by type (e.g., alligator cracking, bleeding, edge cracking, etc.) and severity (e.g., low, medium, or high) based on predefined criteria (e.g., ASTM D6433). IMS has created a suite of custom tools that include rule- based algorithms in conjunction with artificial intelligence to accurately classify pavement distresses. Rutting areas and severity levels