The 4.4 kilometer long bridge on the Tokyo Bay Aqua-Line Expressway in Japan recently overhauled inefficient high pressure sodium lamps for LED lights, according to East Nippon Expressway Company (NEXCO East).

Tokyo Bay Aqua-Line Expressway bridge LED retrofit project used up to 285 LED lights. (All Photo Courtesy belong to  NEXCO East)

Up to 285 LED lights were installed in the project, which is expected to cut power consumption by 40 percent, and reduce carbon emissions by 40 percent or approximately the size of 2.5 soccer fields (18,000 square meters).

Left: High pressure sodium lights were installed in pole lamps before the LED retrofit. Right: LED lights are installed on lower position of the bridge, which lowers the impact of light pollution.

NEXCO East also emphasized the LED lights were installed at a lower position on the bridge compared to the previous high pressure sodium pole lighting installations, which will lower impact from light pollution.

Tokyo Bay Aqua-Line Expressway bridge after LED installation.

The tunnel-bridge expressway spans 14 kilometers (km) from Tokyo Bay to connect Kawasaki in Kanagawa Prefecture with the city of Kisarazu in Chiba Prefecture. The expressway’s 9.6 km underwater tunnel is the world’s fourth-longest underwater tunnel.