Even more dramatic was the drop in vehicle accidents going from 51 in 1996 to 32 in 1997. If you compare the new accident rates with the lesser visible signals at the same locations, our data clearly shows that accident rates actually go down. This is one reason that the City of Chicago has begun to experiment with the use of LED traffic signals. The program is a joint venture between CDOT and the city s Bureau of Electricity. LED has the advantage of providing you with a better light source and a lower operating cost.
Energy costs are significantly lower.
We are observing them and we are going to be collecting data on their energy consumption and visibility ratings. Another advantage to LED signals is that they generally last longer and are more reliable. One thing a LED does, a section of the lens can breakdown or burn out, but you still have all these other diodes in the lens that are still lit up. If you do have a little spot that burns out, the rest of the lens will still be working. One technology that CDOT initially experimented with, and now has begun to make widespread use of, is activated or actuated traffic signals.