Light-emitting diodes, or LEDs, use up to 90 percent less energy than conventional incandescent bulbs while providing comparable illumination. Many cities have opted to use these modern bulbs in their traffic signals to boost longevity and efficiency. While LED use results in lower power bills, it also presents an unanticipated problem: The bulbs do not produce heat sufficient to melt snow and ice. With so little heat radiating from the bulb, traffic signals can become obscured after a winter storm. Authorities report that covered signals have resulted in dozens of accidents. Though LED bulbs seemed ingenious a decade ago, now many cities are reconsidering. Do It!

LED traffic signals may create situations.

A 

hazardous

B 

unavoidable

C 

illegal

D 

competitive

ans correctly