Arizona Department of Transportation (ADOT) conducted a study of technological methods to accurately measure the wait time for trucks crossing into the United States from Mexico at the San Luis II Commercial Port of Entry. ADOT had tested Radio Frequency Identification (RFID) technology to measure wait times, but recognized its constraints in requiring a transponder tag on each vehicle. Anonymous Re-Identification (ARID) technology uses the unique digital signatures of mobile electronic devices, such as smartphones, to detect and match individual vehicles passing pre-defined locations in order to estimate elapsed travel time. Over three days in December 2017, ADOT collected data from Wi-Fi and Bluetooth signals for an evaluation of ARID at the San Luis II Commercial Port of Entry.

A permanent ARID system requires equipment at each detection site and a central software system for data transfer, storage, and reporting. Approximate costs in 2018 were provided by two representative ARID vendors and were consolidated into the cost estimates in Table 1. An RFID system consists of three general categories of equipment, including transponder tags, detection site equipment and a software tool used to collect, store, and report data. Approximate RFID costs from a previous implementation project at the Nogales Port of Entry between 2009 and 2011 were refined to estimate the RFID deployment cost at San Luis II in 2018, shown in Table 2. Operation of the RFID system would also involve ongoing external costs, such as staff time to supply and maintain transponder tags. For the cost estimates, analysts assumed that sensors would be deployed at three locations to provide more refined travel time estimates.

Table 1: Estimated Costs of ARID System Installation

Table 2: Estimated Costs of RFID System Installation