The best-available headlights on 32 of 165 2018 models evaluated by the Insurance Institute for Highway Safety (IIHS) earned the highest rating of good — marking a significant improvement over only two of 95 2016-model headlight systems that earned a good rating.

In addition, for the 2018-model year, the best-available headlights on 58 models garnered the second-highest rating of acceptable. Of the total, 32 models have only marginal-rated headlights, while poor-rated headlights are the only ones available for 43 models.

Approximately half of all fatal crashes nationwide occur in the dark and more than a quarter happen on unlit roads.

While more than 50% of 2018 models it evaluated are available with headlights that do an adequate job of lighting the roadway in the dark, most good-rated headlights are optional or bundled with other features — requiring an additional price tag, according to the institute.

Because a single vehicle model may offer different headlight options, institute engineers evaluated a total of 424 headlight variants on 2018 models. Of these, 67% got either a marginal or poor rating due to inadequate visibility, excessive glare from low beams for oncoming drivers, or both.

Another noteworthy finding, only two 2018 models evaluated — the Genesis G90 and the Lexus NX — come with good-rated headlights, despite the trim or options package.

The best-available headlights on the Chevrolet Volt, Genesis G80, Mercedes-Benz E-Class and Toyota Camry are rated good, while the lowest are rated acceptable. Also, 15 other models have acceptable-rated headlights across the board.

For most other vehicles, consumers have to select a top trim line to get the best available headlight performance, according to the institute.

Some 17 vehicles with good-rated headlights also have poor-rated variants. Among these is the Hyundai Kona, for example. While the LED projector headlights on the high-end Kona give a driver traveling at 65mph ample time to identify obstacles and brake to a stop, the halogen lights on the base-model means a driver would need to go 25 mph slower in order to stop.

Other key findings from the IIHS report include:

• Toyota and its Lexus luxury brand lead the way with the most 2018 models that only offer headlights that rate good or acceptable.

• The Honda Ridgeline is the only pickup with available headlights that earn a good rating. However, the price tag is nearly $12,000 more than the base model, which only comes with poor-rated headlights.

• Correctly aimed low beams light up the road ahead without temporarily blinding drivers of oncoming vehicles. Subaru is among a handful of manufacturers that made running changes to certain 2018 models to improve ratings, mostly by readjusting headlight aim. The Crosstrek moved to a good rating from poor for its best-available headlights, the Forester climbed to acceptable from marginal, and the Outback rose to good from acceptable.

• Additional manufacturers that made similar running changes include Hyundai/Kia, Mazda, Mercedes-Benz, Volkswagen and Volvo.

• High-beam assist is quickly gaining traction — 45% of the 2018 models evaluated have the feature as compared with just 37% in 2017. Vehicles with high-beam assist earn extra credit in IIHS headlight evaluations.