Only one midsize car of the 31 evaluated earned a good rating for its headlights, according to a new study by the Insurance Institute for Highway Safety (IIHS), which also showed that a vehicle’s price tag had little to do with the quality of its headlights.

IIHS focused on the issue as automakers shift to LED or high-intensity discharge lamps for headlights instead of traditional halogen lamps, and use new technology for curve-adaptive headlights that turn based on the direction of the wheels.

“If you’re having trouble seeing behind the wheel at night, it could very well be your headlights and not your eyes that are to blame,” David Zuby, IIHS executive vice president and chief research officer, said in a release on the institute’s website.

The Arlington, Virginia, institute evaluated 31 different midsize vehicles, and because they can be fitted with different headlights, it assigned a total of 82 ratings based on every possible headlight combination available from car dealers. IIHS’ rating system rewards those “that produce ample illumination without excessive glare for drivers of oncoming vehicles.”

Of all the cars and combinations tested by IIHS, only the Toyota Prius v emerged with a good rating, and even that, only when equipped with LED lights and high-beam assist, add-ons that cost a pretty penny and are available only for the most expensive variant. The same vehicle, when equipped with regular halogen lights and without the high-beam assist — which automatically switches between high and low beams, depending on the presence of other vehicles — earned a poor rating.

Another 43 headlight systems earned a poor rating, with the halogen lights on the BMW 3 series being the worst. You would have to drive at 35 mph or slower to be able to avoid a crash in the travel lane.

Mercedes-Benz, whose vehicles also received a poor rating in the study, was “greatly surprised” by the IIHS rankings and is analyzing the results, company spokesman Rob Moran said in an e-mailed statement to Bloomberg.

The Kia Optima provides good visibility with its curve-adaptive headlight system but produces excessive glare for oncoming vehicles on low beam approaches, giving it a poor rating.

The basic halogen lights on the Honda Accord 4-door have no new technology but still earned a high rating of acceptable.

“With about half of traffic deaths occurring either in the dark or in dawn or dusk conditions, improved headlights have the potential to bring about substantial reductions in fatalities,” IIHS’ release says. Rightly so.