On August 5, 1914, the first electric traffic light was installed in Cleveland, Ohio
August 5, 2025
An event every year that begins at 12:00 am on day 5 of August, repeating indefinitely
On August 5, 1914, the first electric traffic light was installed in Cleveland, Ohio. This light consisted of only two colored bulbs, red and green, and was manually operated by a police officer.
Though the traffic light was not a new concept, electricity made it viable and widely-used. Gas-powered electric traffic lights were known to explode – the very first traffic light did so in fact, killing a nearby policeman in 1868.
Did you know? The red, yellow, and green light pattern we are so familiar with today has origins in train signals used on railways.
The human eye is naturally drawn to red, which has the longest ray wavelength and can seen from farther distances. It is also associated with danger.
White or green were initially used to signal “go”, but white fell out of favor as train signal lights commonly had colored filters. When these colored filters fell off on occasion, conductors were left with a white light that signaled “go” no matter what the circumstance. By removing the white light as a “go” signal, conductors would know to proceed with caution or stop when they saw it.
Public officials and drivers soon noted the need for a “slow” or “caution” light. Yellow was a natural color choice. Blue can be easily confused with green, and pink, purple, or orange with red. Yellow is easily distinguishable from both colors.
New York Public Library, Colin Campbell Cooper, c. 1910s
-Written by Anna Zemaitaitis, Communications and Design Officer