- May 24, 2007
- Reaction score
I'd like to see these tests repeated with aftermarket HID, LED and high-output halogen bulbs.
CARS.COM — The Insurance Institute for Highway Safety tested 31 cars for headlight effectiveness, and 19 models, including several luxury cars from BMW and Mercedes-Benz, earned marginal or poor scores.
Related: IIHS Announces 2016 Top Safety Pick List
Federal headlight standards "allow huge variation in the amount of illumination that headlights provide in actual on-road driving," IIHS said, noting that roughly half of all traffic fatalities occur during the dawn, dusk or nighttime. The agency's evaluation, conducted at night, measured how far headlights illuminate the road at various distances — 200 to 500 feet, depending on the test — to a specified level of illumination with the low and high beams. IIHS also tested how much glare the low beams create for oncoming cars. The agency measured performance in a straight line and various curves, and it kept any adjustable-aim lights at their default angles. IIHS said it weighted straight-line and low-beam performance more.
Many cars offer higher-end headlights (LEDs or high-intensity discharge lights that swivel in a curve or automatically switch between high and low beams, for example) as optional equipment over a fixed halogen setup. In most cases, IIHS scored multiple lighting systems offered on each car — a total of 82 lighting variations on 31 models. Even so, the agency noted that 10 of those 31 models had poor scores even with their best-performing systems.
IIHS scores are good, acceptable, marginal and poor. Here's the full list of overall scores for the 2016 models tested; all scores reflect the best-performing system.
Toyota Prius v
Honda Accord sedan
Subaru Outback (models built after November 2015)
BMW 2 Series
BMW 3 Series
Chevrolet Malibu Limited (prior-generation fleet model)
Even among models that scored acceptable or good, securing that score often requires buying an optional headlight system that can be hard to find. Take the Toyota Prius v, the lone car to score good with its optional LED headlights and automatic high beams. Those lights are hard to find: LED headlights come on just 15.5 percent of new 2016 Prius v inventory on Cars.com. The vast majority of cars you'll find at dealerships have halogen lights, which earned a poor IIHS score.
The case is similar for many cars. Of the 11 models that scored acceptable with certain headlights, all but one had marginal or poor scores with other headlights. It's possible the remaining car, the Volkswagen CC, would have been part of the group, too, as IIHS only published results for the CC's upgraded headlights.
The variances in performance were significant. The worst-performing car in the group was the BMW 3 Series, whose standard halogen headlights illuminated only 130 feet ahead on a straightaway at low-beam levels, IIHS said. Contrast that with the Prius v; its LED low beams illuminated nearly 400 feet — a distance the 3 Series' high beams barely reached. (The 3 Series earned a marginal rating with its optional adaptive LED headlights and automatic high beams.) And better technology doesn't always produce superior results: The Honda Accord's standard halogen lights earned an acceptable rating, while its optional LED headlights scored marginal.