Unintended Consequences of LED Traffic Lights – USA


In rush to be energy efficient, number of cities across USA have replaced regular bulbs in traffic lights with LED technology.

Their use seems to be a no-brainer, since these new LED lights are 90% more energy efficient.

Efficiency vs. Effectiveness

In our rush for short-term efficiency, we tend ignore the long-term effectiveness of policy or technology.

In this particular case of LED traffic lights, the policy maker forgot that this technology should be effectively in all use environment.

Law of Unintended Consequences

In this case, Law of Unintended Consequences kicked in. In winter months,  the low heat from these energy efficient LED traffic lights does not melt the snow covering them, rendering them opaque to motorist.

This winter number traffic accidents have been reported attributed to this phenomenon of motorist not able to see the traffic lights that are covered by  snow.

This is an excellent example of technologist not anticipating all the functions of current technology i.e. energy efficiency is great, however, firstly, the main purpose of traffic lights – i.e. visibility throughout the year, even winter months, is the primary aim and energy efficiency is secondary.

Suggested Solutions to over come Unintended Consequences

  1.  Installing weather shields,

  2. Adding heating elements like those used in airport runway lights, or

  3. Coating the lights with water-repellent substances.


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