Installation of traffic signal

I came across the installation of traffic signal on my way to work this morning. I had seen it up close for the first time. The signal was bigger than I thougt. One of the three lights was much bigger than my face. The signal in Japan has three lights, that is blue, yellow, red starting from left. Each meaning was, blue:go ahead, yellow:caution, red:stop. The signals had replaced by the new one which was used LED from around a year ago. We were now able to see the signals clearly even on a sunny day. I guess LED lights could conserve energy also.