■Interview with engineer in charge
What motivated you to develop the traffic signal controller?
We were inspired by the large-scale traffic disruption caused by power outages after the Great East Japan Earthquake. After the Earthquake, rolling blackouts were implemented in Tokyo. Many police officers were called out to direct traffic. To meet increasing demand for traffic signal controllers that could prevent traffic lights from turning off, we started to develop a traffic signal controller with a built-in battery.
What problems did you face in the course of the development?
Since the traffic signal controllers are installed near intersections where automobiles and pedestrians pass and cross, the dimensions of the enclosures are restricted. We made a supreme effort to build a battery in a conventional enclosure.
Though we used smaller parts for the switching device and changed the parts arrangement in the enclosure, we could not secure sufficient space to house a battery in the enclosure. As an alternative, we developed a smaller-sized battery jointly with one of our associated companies. The newly developed battery was small enough to be housed in a conventional enclosure. Safety is required of traffic signal controllers because they are installed near places through which automobiles and pedestrians pass. Within a restricted development period of approximately eight months, we took sufficient time to assess and ensure the safety of this product.