Cities around the country are changing colors, from a warm yellow shade to more of an institutional blue. The change comes from above: They’re replacing old streetlight bulbs with new, energy-efficient LED bulbs. Columbus city officials say the transition will cut public lighting costs in half, but LED lights have raised concerns from some residents and medical experts. The biggest reason for the change, says James Gross of the Columbus Division of Power, is money. LEDs require a lot less electricity to light up neighborhoods.