The Long and Lighted Road: Lighting and Driving
Brake and Turn Signals
Automotive Signal Lights
Although motorists often complain that some drivers don't know they exist or how to use them, all cars these days come equipped with blinking turn signals letting the car behind you know what you're up to. That certainly wasn't the case with the earliest cars, though. I still remember drivers using standard hand signals into the early sixties — you know, the ones you had to learn to pass your driver's test: for left you put your left arm straight out the window parallel to the ground, for right you rested your left elbow on the window, raising your forearm up with your hand open. And if you wanted to stop you signaled that intention, as well, by putting your left arm out parallel to the road and angling it downward. These hand signals were required whether it was sunny and fair or pouring buckets. Drivers of early historical cars, in fact, still have to know and use hand signals.
The fact is that more than half of all traffic accidents involving two automobiles occur when both vehicles are traveling in the same direction. Because of this, brake lights and turn signals began to appear on vehicles as early as 1906. For most of the time since then, tungsten filament lamps have been used as the main light source in vehicular signaling. However, the development of alternative sources for brake and turn signals has grown during the last ten to twenty years, and more and more automobiles are using light emitting diode (LED) or neon light sources in automotive signals.
Nowadays turn signals are required for vehicles driven on public roads — unless they're antique vehicles that did not come with turn signals. Some owners of such cars, though, feel a lot safer installing after-market turn signal mechanisms. Buick was the first U.S. automaker to offer factory-installed flashing turn signals. Introduced in 1939 as a safety feature, the new-fangled feature was advertised as the "Flash-Way Directional Signal" operated from a switch on the new "Handi-shift" column-mounted shifter. The flashing signals only operated on the rear lights. In 1940 Buick enhanced the directional indicators by extending the signals to front lights and adding a self-canceling mechanism.
Though the basic turn signal technology hasn't changed in years, future improvements may include increased strength and durability for parts that are consistently used and abused, an alert when the turn signal switches off even before we've started our turn, and customizable turn-signal tones. While there's still a need for such innovations, we're all better off relying on technological wizardry rather than hand signals.