The traffic light, as we know it, didn't show up until 1920 with the first one placed at Woodward and Michigan Avenues. InventEd by a Detroit policeman. Never made a dime off of it.....sometimes it is like that.
The 'stop sign' also came from Michigan in 1915.
The first State to require license plates was New York in 1901. Plates weren't standardized until 1957 I bring this up because the cars in the film have plates and look how many cars there are.
I am a little surprised that there aren't any motorcycles since the first production motorcycle in the States was in 1898.
By the way, Europe beat us on all the above except for the 3 color timed traffic light. They did have a 2 color light starting in 1868.
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