Traffic lights

[tigerlily11]

I'm just wondering about this but I just sa a picture of the LA Marathon. It has in the top corner a set of trffic lights. Now I was told many years ago that in the USA traffic lights were just red and green and there was no amber.
Was I miss informed?
Thanks for your time.

[Ethel]

This Los Angeles advice site clearly mentions the amber traffic light.

http://www.hollywoodusa.co.uk/travelfacts.htm

You may not have been misinformed though - the traffic light system has changed over the years.

This from Wikipedia states the USA used to have a two light red - green system:

As early as 1912 in Salt Lake City, Utah, policeman Lester Wire set up the first red-green electric traffic lights. On 5 August 1914, the American Traffic Signal Company installed a traffic signal system on the corner of 105th Street and Euclid Avenue in Cleveland, Ohio. Based on the design of James Hoge, it had two colors, red and green, and a buzzer to provide a warning for color changes. The first four-way, three-color traffic light was created by police officer William Potts in Detroit in 1920.[1

[sddsddean]

All the TL's I've seen in the US are normal 3 colour. However, it is quite common practice during off peak periods for the red and green to be switched off and all the ambers left flashing, so that in light traffic you treat the junction with caution, but no traffic light control.