  Vehicular sensor network (VSN) is an emerging technology, which combines
wireless communication offered by vehicular ad hoc networks (VANET) with
sensing devices installed in vehicles. VSN creates a huge opportunity to extend
the road-side sensor infrastructure of existing traffic control systems. The
efficient use of the wireless communication medium is one of the basic issues
in VSN applications development. This paper introduces a novel method of
selective data collection for traffic control applications, which provides a
significant reduction in data amounts transmitted through VSN. The underlying
idea is to detect the necessity of data transfers on the basis of uncertainty
determination of the traffic control decisions. According to the proposed
approach, sensor data are transmitted from vehicles to the control node only at
selected time moments. Data collected in VSN are processed using on-line
traffic simulation technique, which enables traffic flow prediction,
performance evaluation of control strategies and uncertainty estimation. If
precision of the resulting information is insufficient, the optimal control
strategy cannot be derived without ambiguity. As a result the control decision
becomes uncertain and it is a signal informing that new traffic data from VSN
are necessary to provide more precise prediction and to reduce the uncertainty
of decision. The proposed method can be applied in traffic control systems of
different types e.g. traffic signals, variable speed limits, and dynamic route
guidance. The effectiveness of this method is illustrated in an experimental
study on traffic control at signalised intersection.
