State agencies have implemented weigh-in-motion (WIM) sensors for years to assess and monitor various aspects of highway commercial motor vehicle traffic. This study analyzes 3.5 years of WIM data from 33 WIM sites provided by the Indiana Department of Transportation (INDOT) and compares systematic procedures to identify WIM locations with measurement errors. The following areas are examined: WIM accuracy and precision, class 9 front axle weight, left-right front axle residual, and impact of pavement smoothing on WIM performance. The statistical distribution of Class 9 truck’s front axle weight as a performance metric is suggested for automated online software. This study also assessed the accuracy and precision of two WIM sites by direct comparison with weight data obtained at Indiana State Police certified weigh scales. A 5 month study on I-94 collected 564 static weights and found that 98% of the WIM weights were within ± 5% of the static weights. A second study on I-70 collected 262 static weights and found that 87% of the WIM weights were within ± 5% of the static weights after statistical adjustment.

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weigh-in-motion, WIM, calibration, WIM maintenance, WIM dashboard development

SPR Number


Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, Indiana

Date of this Version