Revenge of the Third Brake Light

Here's one of my little techno-peeves: The abundance of cars with third brake lights that don't work.

Well-intentioned technology can "bite back", to use Edward Tenner's phrase from his book Why Things Bite Back : Technology and the Revenge of Unintended Consequences.  (He or Donald Norman or someone like that may well have already discussed this issue somewhere... if so I don't recall.)

Roughly 1 in 20 cars I see has a burnt-out third brake light, and I'd argue that a broken third brake light is more hazardous than having no third brake light at all.

According to an article from the American Psychological Association, the third brake light was made mandatory on US cars in 1986, based on studies that showed fewer rear-end collisions in cars equipped with them.  The government's study showed a 4.3% reduction in accidents.  But that study probably didn't anticipate 5% broken lights.

When a third brake light is broken it's worse than not having it at all, because of (a) adaptation to seeing a brake signal closer to our center of vision, and (b) the negative visual cue of the unlit third brake light hardware.

It seems people don't notice or fix burnt out third brake bulbs as quickly as other bulbs, for whatever reason.  That could probably be remedied quite easily in the wiring, by using a buzzer or some other cue as is done with turn signals.  It's kind of insane, actually, that today's cars don't warn the driver when any lights are out.