Bluetooth-based Floating Car Observer: Model Evaluation using Simulation and Field Measurements

Kurzfassung

This paper depicts a Bluetooth-enabled Floating Car Observer approach to monitor Bluetooth-enabled traffic participants, in order to generate real-time spatiotemporal traffic data in a road network. By using Bluetooth as sensing module traffic objects such as vehicles, cyclists, pedestrians which are equipped with Bluetooth-enabled devices can be observed. Due to the specific Bluetooth connection establishment behaviour a Bluetooth-enabled device can be recognised on every point within the road network by using its unique identifier address. Hence, particularly desired traffic information such as origin-destination information can be derived. A major drawback of that kind of traffic monitoring is the prediction of the likelihood of a (re)-detection of such a Bluetooth-enabled traffic object. Since Bluetooth has a specific detection range and a complex connection establishment process, it is not clear, how long it takes to detect a device and where that device was exactly recognised within detection range. This paper tries to answer this question by introducing a theoretical model to describe the detection process as an exponential distribution and to determine it specific properties such as the encounter rate of Bluetooth-FCO and detectable traffic objects. To evaluate the analytical model, simulations as well as laboratory and field experiments with Bluetooth observers and detectable Bluetooth devices were conducted to measure detection rates as a function of encounter times.