Turn signals are a fundamental automotive safety feature, but their implementation was not uniform for decades. Before modern mechanical signals became standard, drivers worldwide relied on hand gestures, which differed significantly between countries.
In the early 1900s, mechanical 'trafficators' and later illuminated arrows appeared, but U.S. law didn't mandate turn signals until 1953. This lack of standardization meant drivers had to learn hand signals, which varied internationally and could cause confusion.
Common U.S. signals included a straight left arm for a left turn and a right arm bent upward for a right turn. However, the UK, with right-hand drive, used a forward-facing right palm for a right turn and a distinctive up-and-down wave to signal slowing down. Australia and Spain also had their own variations.
While electric blinkers, first used by Buick in 1939, eventually made hand signals largely obsolete, they remain crucial knowledge for cyclists and drivers with malfunctioning lights. The history highlights the patchwork road to global driving communication standards.