Right hand to left hand drive change date

[47COE]

With a 36 pickup, a 41 and 42 COE, I normally hang out on the early V8 forum.

But I also volunteer in the photo archives of my county museum.

What I'd like to know is the date range when the U.S. changed over exclusively to left hand steering.

I figure the people here would have a better idea of the time frame of the changeover. I think it was in the teens, but I don't know if it was gradual or all happened in a one or two year period.

That would help in dating old photos that have early cars.


Thanks,

Tom