Dr. Tetsuji Takeuchi   Research

It is certain that we will have two new situations in the near future. One is the increase of underpass and tunnel to solve the traffic jam at crossings in cities. Another is the relative increase of elderly people compared to young people in population. These two situations are closely related in view of visual performance. Inside tunnels the illumination level is low compared the outs ide. When people approach a tunnel by driving cars they look inside the dark tunnel from bright outside and obstructs on the roads in the tunnel can not be seen clearly because of the difference of illuminance of outside and inside. Proper illumination in tunnels must be installed for the safety driving. The dangerous situation becomes still worse for elderly people because of cataract which scatters the environment light in their eyes and to them the inside tunnel appear as a black hole. In this laboratory the visual performance to detect obstructs in a tunnel is investigated both with young and elderly people and proper illumination for the tunnel will be found. In the laboratory a simulated tunnel is constructed and various obstructs for detection are presented to observers under various illumination both outside and inside the tunnel. An observer approaches the simulated tunnel and a proper illumination of the inside of the tunnel will be obtained to easily detect the obstructs in the tunnel. The results should be valuable in designing underpasses and tunnels in this country. The laboratory is supervised by Dr. Tetsuji Takeuchi, a former president of Japan Electric Lamp Manufacturers Association (JELMA). He is an expert in tunnel lightning and has many experiences in designing tunnel illumination for express ways in Japan.