You got it right on the head, from your link: 

The BAR greeter also provides the driver with a consumer information
handout (Appendix D) that further explains the Roadside Inspection Program. If the driver
agrees to participate in the inspection process, the vehicle is inspected. If the driver refuses, the
vehicle is released and another vehicle is quickly directed into the test lane. The license plate
numbers of vehicles whose operators decline to participate in the Roadside Inspection Program
are recorded and entered into a laptop computer for later analysis.
handout (Appendix D) that further explains the Roadside Inspection Program. If the driver
agrees to participate in the inspection process, the vehicle is inspected. If the driver refuses, the
vehicle is released and another vehicle is quickly directed into the test lane. The license plate
numbers of vehicles whose operators decline to participate in the Roadside Inspection Program
are recorded and entered into a laptop computer for later analysis.

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