Thursday, April 29, 2010

Traffic Signals and LEDs:

More Unintended Consequences

I've addressed the theme of unintended consequences before, but another example of an unintended consequence of an energy-saving measure recently came to my attention. This one, entitled "LED Signals Seen as Potential Hazard," was from a New York Times report a few weeks ago. It concluded that LED traffic signals installed to save energy have been found to perform poorly in some bad weather conditions. Specifically, the very fact that LED traffic lights do not emit as much waste heat as conventional bulbs means that they are less able to melt the ice and snow in the winter. There are now documented cases of the ice and snow accumulating and obscuring the light signal, resulting in injuries and fatalities from traffic accidents.

Although this is another discussion that at first glance seems to stray far from the nuclear field, it is a concern I've mentioned before because it is emblematic of the kinds of issues that must be addressed as we try to transition to energy technologies that are more efficient and/or less carbon intensive. In that sense, as I'll note, it has a message for the nuclear community as well.

I'm not completely sure why the scientists and engineers have not been able to develop the ability to try to project such consequences. I do realize it is difficult. I also realize that it is the same kind of issue that comes up for every technology and every consumer product, whether it is an electric power station or a children's toy. We've got to anticipate ways that people will misuse appliances. We've got to anticipate all conditions under which a system may operate--rain, snow, heat, humidity. We've got to anticipate the resource requirements, competition with other needs, etc. when a new technology grows from limited to large-scale use. (A good example is the impacts of biomass production on food costs.) We've got to look at the entire life cycle of the technology. (An example here is the disposal of energy-efficient light bulbs.)

Although LED traffic signals may seem quite far afield from the nuclear discipline and although the most difficult issues of projecting the impacts of new technologies at the moment seem to be outside the nuclear field, I think there is a message here for the nuclear community as well. For example, questions are raised from time to time about the impacts of the increased use of nuclear power. Will there be enough uranium? What will the land impacts be of mining lower-grade ores?

There may be good answers for such questions, but the time to explore them should be before people are injured or killed because of snow-covered traffic signals. Likewise, most of us can probably address the questions about uranium, at least in a qualitative way, but the questions are good ones, and will need better answers if we are to realize a nuclear renaissance.

I don't know how to make sure that we do a better job in the future of "connecting the dots" in the future to assure that people who design LED traffic lights do not wait for someone to die before they figure out that the lights will not generate enough heat to melt snow and ice. I can only hope all of us in the business of trying to introduce new technologies are learning that technologies can have unintended consequences and are consciously and methodically trying to anticipate in advance what these might be.


1 comment:

  1. Perhaps we need to implant some fission product waste into the cover to provide the missing heat. ;-)

    I think this "complaint" about LED traffic lights is a classic example of bad-faith assessment of trade-offs. Changing to LEDs changes the trade-off - it doesn't mean that any new problem invalidates that decision. It's easy to imagine mechanisms that could help this clogging problem and it's even easier to look up the problems that incandescent traffic lights have had.