The prototype of the car turn signal can be traced back to 1914, when Hollywood movie star Florence Lawrence invented a manually button-controlled turn indicator but did not apply for a patent. In 1925, Edgar Walz obtained a patent for a turn signal device, but it was not widely adopted by car manufacturers. A milestone for modern electronic turn signals was in 1936 when Buick first equipped a light system controlled by relays. In 1939, this technology was named "Flash-Way Direction Signal" and became a standard feature for brands like Buick. Early turn signals used the principle of bimetallic strips to achieve flashing, while most now have been upgraded to LED light sources. The standard flashing frequency is 60 to 120 times per minute, and an abnormally fast frequency usually indicates a bulb failure. The amber colour design of turn signals has become the global mainstream due to its strong penetration, with only a few countries allowing red. This invention completely replaced the primitive method of drivers gesturing with their hands, significantly improving driving safety. Later, it also gave rise to the hazard warning light function, which is used in emergency parking or low-visibility scenarios. Malaysian regulations also require turn signals to be amber, and their functional integrity is inspected during vehicle annual inspections.
