LED bulbs. But this simple switch is not limited to the home. Some very important lights in South Bend are saving some serious money. The city has more than 205 intersections, add up all the individual lights and that is over 4000 bulbs. "The reason that we changed the bulbs is because incandescent bulbs are inefficient. By changing an incandescent bulb to an LED fixture, you save roughly 85 percent of the energy,” Rob Nichols said.