LED headlights, currently a technology for pricey luxury cars, are starting to enter the mass market

"This is a huge transition," Allgeier said in a Sept. 4 interview. Prices "have been changing quite rapidly. Over the last two or three years, there has been a substantial improvement of price and performance."

Because they do not generate light from heat, LEDs are more energy efficient than halogen bulbs. A halogen headlight might require 65 watts, while an LED headlight might need only 15 watts or so.

Automakers favor LEDs because they are durable, compact and energy-efficient, but they are still relatively expensive. A no-frills halogen headlight might cost automakers $20 or so, while a xenon headlight generally ranges from $60 to $80. LED headlights cost roughly twice as much as xenon headlights, although the cost is declining fast