EPMS control and a NO/sub x/ sensor for traffic control systems

Environment protection management systems (EPMS) are a component of the "UTMS 21" project formulated by the Japanese National Police Agency. EPMS is a general term for systems that measure the pollutants emitted by road traffic and they use a variety of means, including the control of traffic flows, provision of traffic information and guidance on recommended routes for individual vehicles, to reduce the amount of pollutants emitted. We began our research in 1994, and in 1996 demonstrated, in general field experiments, a measurement and control system that reduced emissions of NO/sub x/. In 1998, we developed a small, low-cost NO/sub x/ sensor that is suitable for use outdoors in traffic control systems. This paper describes the control techniques we use to reduce NO/sub x/, the results of field testing and the principles underlying our NO/sub x/ sensor for traffic control systems.