Traffic Generator for Evaluating the Accuracy of Traffic Recording Devices with Loop Detectors

In this paper, a PC-Based traffic generator was designed and implemented which can be used to evaluate the accuracy of speed/volume monitoring function of ATR (Automated Traffic Recorder) equipped with up to 8 inductive loop detectors. Although the two axle sensor configuration can be used to perform speed monitoring, researchers concluded that the loop detector was the best of the sensors studied. The traffic generator consists of hardware module and control software. The hardware module includes interface circuitry and loop sensor simulators. The loop sensor simulator was designed to conform to both major ATR manufacture’s specifications and the NEMA standard. The control software was written to control the printer port of the PC, which is connected to the hardware interface circuit, and direct the test vehicle signature data to the designated loop sensor simulator(s) as specified by the test vehicle signature data. In this research, a test vehicle of FHWA Type 2 with length of 11.5’ is used. The simulation results prove that the traffic generator can produce test traffic with mix of speeds precisely and repeatedly. More importantly, the tests can be conducted in the laboratory with operational efficiency and safety.