The main goal of the field operational test was to evaluate the performance of the SIRIS prototype and determine if the system was viable for CMV enforcement. From March 2010 to September 2010, the Oak Ridge National Laboratory facilitated the field test at the Greene County Inspection Station (IS) located on I-81 in Greeneville, Tennessee.
During the testing period, all CMVs traveling on I-81 South were diverted onto a high-speed bypass lane. Sample sets of four consecutive CMVs were directed onto another lane that headed towards the pit-scale. These trucks were required to brake, reduce speed, and pass by the SIRIS camera. One vehicle in each sample set was then to receive a full Level-1 inspection and have their brakes evaluated using a Performance-Based Brake Tester (PBBT) machine. Enforcement personnel conducting the inspections were not allowed to view the SIRIS data before each inspection. CMVs found to have defects were subject to normal enforcement protocols.
Overall, 413 vehicles were randomly selected from the mainline and 384 of them were successfully scanned by the SIRIS. To evaluate performance, the SIRIS data were compared to the inspection data.
- Thirty-six (36) of the 384 vehicles scanned by SIRIS displayed a potential brake or tire violation.
- All 36 of the vehicles flagged were subjected to a Level-1 inspection which resulted in 30 (83.3 percent) of these vehicles being placed out-of-service for a related violation, and 31 (86.11 percent) identified as having a flaw of some type relative to brakes, tires, or wheel bearings.