(Unlike automotive systems, bicycle turn signals don’t turn themselves off automatically after you’ve made your turn, for example. Although it eliminates wiring, it still needs batteries and has many of the same problems as other systems.

Sharper Image offers a wireless bicycle turn signal system. The system is exposed to water, making it likely to fail. Unlike a car a bicycle is narrow, so the turn indicators are close together, making them harder to interpret. Your once-elegant bike is now festooned with wires, switches and electronic components. You can buy battery-powered signals that bolt to your bike, for example. There have been numerous suggested solutions to the bike-signal problem. These are rapidly becoming a lost communication form, consigned to the dustbin of history along with Morse code, smoke signals and the coloured flags Admiral Nelson used to communicate with his fleet at the Battle of Trafalgar. The rise of easy-to-understand electronic turn signals has gradually killed our understanding of hand signals. Imagine if electronic turn signals worked like bicycle signals: There would be a single signal, on the left side, that would blink in different patterns to indicate a right or left turn. It is also intuitive: The right blinker indicates a right turn and the left blinker indicates a left turn.

Today, the electronic automotive turn signal is universal.

Hand turn signals