This week, the city of Canton in Ohio, U.S., and American Electric Power will launch an experimental program to switch high pressure sodium lights with LED lights in four “cobra head” street lights over Market Avenue near 40th Street. Two years ago, Canton replaced the sodium lights in the decorative lampposts along a one-mile stretch of Tuscarawas Street with LED lights. Five years ago, the city began switching traffic signals from incandescent bulbs to LED lights.