Released earlier today, the study reveals the Toyota Prius v is the only midsize car to earn a "good rating" in the organization's first-ever headlight tests. The IIHS tested a total of 31 models and found that only 11 cars earned an acceptable rating when equipped with the best available headlights. Nine models received a marginal rating, while the remaining ten vehicles were left with a poor headlight rating.
Premium automakers have embraced high-tech lighting technology but surprisingly the study found a number of luxury models are equipped with poor headlights including the Cadillac ATS as well as the Mercedes CLA and C Class. The IIHS goes on to say the BMW 3 Series has the worst halogen headlights but the optional LED headlights significantly improve the situation.
The headlights were evaluated on the track with a special device that measures the amount of light produced by the vehicle's high and low beams. When the data is collected, "IIHS engineers compare its visibility and glare measurements to those of a hypothetical ideal headlight system and use a scheme of demerits to determine the rating."
While the U.S. government has safety standards for headlights, the IIHS says the standards allow for a huge variation in the amount of illumination that is provided by the headlights. The organization notes this is a problem as nearly half of all traffic deaths occur at night or in low light situations such as dawn or dusk.
Check out the source link to see detailed ratings and learn more about the testing process