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First 3 Color Traffic Signal This is first ever 3 color traffic signal, placed in service in 1920. It was designed by Police Superintendant William Potts of Detroit. It used three 200 watt 220v bulbs and railroad lenses. Obviously it displayed red on the top and green on the bottom on one street, and green on the top and red on the bottom on the cross street. Potts is credited with designing the first 4-way traffic signal.) (Prior to the Detroit signal a 2 color signal system was designed by Salt Lake City policeman Lester Wire but I'm not aware of any photos of it.) Keywords: Traffic_Lights

First 3 Color Traffic Signal

This is first ever 3 color traffic signal, placed in service in 1920. It was designed by Police Superintendant William Potts of Detroit. It used three 200 watt 220v bulbs and railroad lenses. Obviously it displayed red on the top and green on the bottom on one street, and green on the top and red on the bottom on the cross street. Potts is credited with designing the first 4-way traffic signal.)

(Prior to the Detroit signal a 2 color signal system was designed by Salt Lake City policeman Lester Wire but I'm not aware of any photos of it.)

econo_fire_signal01.jpg sargent_sowell_beacon_truckee.jpg potts_signal_intersection.jpg darley02.jpg autoflow_4-key_timer.jpg
File information
Filename:potts_signal_intersection.jpg
Album name:Nevada Willis / Traffic Signals
Keywords:Traffic_Lights
Filesize:48 KiB
Date added:Apr 03, 2011
Dimensions:600 x 484 pixels
Displayed:208 times
URL:http://www.galleryoflights.org/mb/gallery/displayimage.php?pid=5875
Favorites:Add to Favorites

Comment 1 to 5 of 5
Page: 1

GullWhiz   [Apr 03, 2011 at 05:27 PM]
I was doing search myself and found same thing....4 inch lens!

I saw a page with over 60 pats. of designs..some were really ODDBALLS! Shocked The oldest and more like the current design I also saw was from 1917 designed by William Ghiglieri.

Why was there a cop with old style stick traffic light if there was one 3 light traffic light up there already! Laughing
SeanB~1   [Apr 03, 2011 at 07:54 PM]
Probably there to make the drivers aware of this brand new technology for the time.
rjluna2   [Apr 03, 2011 at 08:44 PM]
You can actually see this photo is dated April, 25th, 1922 Very Happy
Nevada Willis   [Apr 04, 2011 at 02:26 AM]
For the first couple of years the signals were simply adjuncts for the traffic police. Drivers of vehicles and horse drawn wagons might not necessarily see the policemen in the intersection. Some intersections required three policemen to direct traffic. This modern invention allowed drivers who might be blinded from the policeman by vehicles ahead to see an overhead signal indication and now one policeman could control the intersection, making sure drivers obeyed the signals. I don't know if Detroit did it but many early signals were either controlled by the policeman who turned a sign connected to a switch or who threw a switch, or if they were remotely controlled they loften had gongs or electric whistles to let the officer know that the signal was changing phases. I can remember as a kid traffic policemen in the centers of busy intersections making sure drivers obeyed the signals. Dunno what they would have done if someone disobeyed a signal and kept on going. Mad
basilicon89   [Apr 04, 2011 at 04:19 AM]
A buddy of mine did a replica of the Potts signal, all within an inch to the original in height, width and depth. I've seen it several times in person. But you guys can see it online HERE

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