How smart traffic signals may ease your commute
http://www.bbc.com/autos/story/20150317-how-smart-traffic-signals-may-ease-your-commute
18 March 2015
信号の有り難さ
中国はすごいですね
How smart traffic signals may ease your commute
http://www.bbc.com/autos/story/20150317-how-smart-traffic-signals-may-ease-your-commute
18 March 2015
信号の有り難さ
中国はすごいですね