I recall reading somewhere that in the 1930's when the standard cars only had one tail light some state mandated a right side light be installed. Does anyone recall which states they were ?
I don't personally know, but found an AACA discussion where someone posted that two states required two tail lights back then - Missouri and Washington.
1957 West Virginia started state inspections. ALL vehicles required a left and right tail and brake lights. I can't find where self canceling turn signals were required. Probably '58.
1952 Chevy wagons only had one center brake tail light. '53's all had left and right tail and brake.
1955 Chevy PU's, was the final year that the right tail/brake light was an option.
I'm not sure when Dodge and Ford PU's last year for a right light was optional.