It’s always been a goal of mine to make Jalopnik the best source for turn indicator-related information and commentary on the internet. That’s why I’m both so impressed at the work that went into this video and a bit ashamed it didn’t occur to me to think this through. Finally, someone has done the math to show exactly how much it costs a driver to use their blinkers.

If the accent wasn’t a clue, the video was not done by an American, which is why it suggests that cars have six indicators: in Europe and a number of other parts of the world, amber indicator repeaters are used on the front quarter-panel of a car. In the US, only four lights are required for turn indicators, so you may wish to adjust the math accordingly.

Anyway, here’s the full video, from a channel called Chapter S:

In case you’re not able to watch it, the conclusion arrived at is that it costs between 21¢ and and 29¢ per year to use your indicators in the U.S.

The basic formula used to arrive at this conclusion is pleasing complex: assuming the blinkers will be used for about five seconds, with the light bulbs from the signals using about 0.08W of energy/second. Like I said, with two less lights we could possibly reduce that for American-market cars.

Then, we take the energy content of gasoline, 46.7MJ/kg, and the Chapter S team computes that a liter of gasoline contains 35MJ of energy. Then, they find that an average gasoline engine’s efficiency to be about 25 to 26% efficient, and the car’s alternator’s efficiency at about 70%, so when you combine the two you get the rather depressing number of 17.5% efficiency of a gas motor converting fuel to electrical power.

So, that means there’s 1.7KW of electrical energy in every liter of gasoline to go through the engine. Now, with the indicators needing 0.08W, 0.000008L of gasoline can provide that energy, but when you’re using a system with 17.5% efficiency, it’s going to need 0.00005L of gasoline to do it.