Roadway Substructure Evaluation in Idaho Transportation Department's District 4 and District 6

Infrasense developed a roadway structure database to assist the Idaho Transportation Department (ITD) in its future project planning and design efforts and to ultimately advance the condition of the roadway to an acceptable level.  The roadway structure database was generated primarily with data from ground penetrating radar (GPR) and falling weight deflectometer (FWD) and Traffic Speed Deflectometer (TSD) testing. The non-destructive test data was complemented with data from direct boring and core sampling at 1 mile intervals. The projects focused on two specific corridors: SH-75 between Stanley and Clayton, with a segment length of about 28 miles; and US-26 between Swan Valley and the Wyoming state line, with a segment length of about 29 miles. 

The roadway structure database includes layer thickness, layer moduli, structural number, and calculated remaining life estimates at 0.1 mile increments. This structure has been set up as a Microsoft Access ".accdb" file and also as an ARCMap file database. The database structure provides ITD personnel with easy access to the data and simple and visual means to assess the data, as shown in the sample below. The pavement corridors were divided into segments based on remaining life estimates, and rehabilitation recommendations have been developed for each segment.

A larger network-level pavement evaluation project with similar objectives is currently in progress. Over 1000 miles of pavement data was collected in August, 2015, and the analysis phase of the project is ongoing.