Why cars in the US have red turn signals (but other countries use amber)

If you've ever traveled abroad, you might have noticed that car turn signals aren't always red like in the US. Why is this ...
abc27

Does a ‘Right Turn Signal’ sign mean ‘No Turn on Red’ in Pennsylvania?

(WHTM) — While turning right on a red light is a common maneuver, some signs may not allow it. Some signals have signs that explicitly say “No Turn On Red,” but others have signs that say “Red Light ...
Jalopnik

How Different Countries Tackled Hand Signals Before Mechanical Turn Signals Were Invented

Turn signals are one of the earliest automotive safety features. In the early 1900s, some cars came with mechanical arm "trafficators" that would pop out of either side of the car to indicate a turn.