In the early days of automobiles it wasn’t necessary to show others which way you went. You mostly had the roads to yourself, at least in a car. Regular road users at the time – wagons and carriages – either didn’t indicate when turning at all (mostly) or the driver casually indicated by hand (maybe in towns). At the beginning of the 20th century, if motorists wanted to indicate where they were going, they simply held their arm out of the car, which was mostly open. When going the other way they bent their arms over their heads in an angle. By the way, this method was still used by American Jeep drivers during World War II.
With increasing traffic these methods became annoying and proved not to be very effective, so even before World War I there were suggestions to introduce signaling. At first this only applied to America, of course, since the roads there were busier than anywhere else. Just like in the Old World, the railway and its semaphore signals were the inspiration. The big difference was that they moved quicker in a car, and in a rhythm. Trafficators were born.
They didn’t move on their own though. The gentleman driver or chauffeur had to keep the movement alive via Bowden cables. In other words, in order to indicate he had to pull a handle keeping strict time.Over time, drivers got annoyed by this way of indicating. In the mid-1920s initial solutions were introduced to the market which took over part of the job. Bosch for instance had an automatic trafficator. It was suited better for driving at night because it was illuminated. Even though it was soon obvious that the trafficators, which were mostly attached to the B pillar, couldn’t be seen from certain angles, the technology survived until after World War II. At least in Europe. In the US they had electric indicators mounted on the roof as early as the 1940s.
In 1958, the ECE first regulated car lighting at international level in Europe. Trafficators were not mentioned anymore. Rule number 6 has since stated what indicators must look like. Since round about 1960, new cars have been delivered following this rule. Older cars had to be modified in Germany by 1964 and trafficators disappeared from the B pillars. For many years the nowclosed‑off ducts could still be seen in cars such as older VW Beetles.Originally, 18‑watt lamps were used, but since the 1970s 21 watts – or more recently LEDs – have been commonly used. Since the beginning of the 1990s, the rules have also allowed amber lamps within white lights. A few years later side repeaters became mandatory in Europe.
The only thing that remained of the trafficator is the word itself. Some older people still use it when talking about indicators.