Study: U.S. Headlights Darker, More Dangerous

Failure to allow for new technology darkens roads, increases crash risk


DENVER (April 16, 2019) – It's just more dangerous to drive when the sun's down: Nearly 52 percent of all driver fatalities in the United States and 71 percent of pedestrian deaths occur at night, despite the fact that only a quarter of all automotive travel takes place in the dark.

Why? In part, per new research from AAA, federal headlight standards just aren't up to snuff: European and Canadian vehicles with adaptive driving beam headlights (ADB) increase roadway lighting by as much as 86 percent when compared to U.S. low beam headlights. ADB headlights are not permitted under U.S. standards.

"Driving at night can be needlessly dangerous in America," said AAA Colorado spokesman Skyler McKinley. "One simple policy change will unleash technology that already exists, markedly improving roadway visibility and saving lives. It's time we catch up."

Previous AAA research found that a majority of Americans (64 percent) do not regularly use their high beams. That means when driving at moderate speeds (~40mph) with low beams on, motorists will not have enough time to appropriately react to something or someone in the roadway. High beams, by comparison, improve forward illumination by 28 percent and are much more effective at providing the proper amount of light when traveling at higher speeds. With ADB, the high beams are always on and, when another vehicle is detected, the area occupied by that vehicle is shaded to prevent glare that would otherwise interfere with the other driver's field of vision.

Some newer U.S. vehicles are equipped with a similar technology that automatically switches between high and low beam. While that technology does increase visibility, it doesn't when other vehicles are present -- as the car will switch from high to low beams upon detecting another vehicle, thereby losing the benefit of the additional light. 

U.S. headlight standards also fall short when it comes to compliance testing. At present, just the headlamp assembly is evaluated as a stand-alone part in a static environment. Lab testing simply cannot capture critical aspects of on-road, in-use illuminance and performance, especially when evaluating a dynamic technology such as ADB. The performance of these systems is dependent on the presence and location of other vehicles, as well as the camera/sensor, software, and mechanism used to control the beam pattern. None of that is permitted in an assembly-only assessment conducted in a laboratory.

"Any motorist will tell you that real-world driving does not take place in a lab," McKinley said. "Roads vary in so many ways, a fact Coloradans know well. Some roads have hills. Some have sharp turns. Others have no roadway lighting. By failing to conduct track testing, we lose a lot of valuable insight into how we can improve headlight technology."

Following a petition from Toyota, the National Highway Traffic Safety Administration (NHTSA) proposed an amendment last fall to allow manufacturers the option of equipping vehicles with ADB systems. AAA submitted comments to NHTSA regarding the proposed changes along with supporting primary research in an effort to provide insight into the performance of ADB as it exists today.

A new headlight standard and testing protocol is likely still a few years away. For now, drivers need to take other precautions when driving at night. AAA recommends:

  • When driving after dark on unlit roadways, use high beams whenever possible. There is a difference between seeing roadway markings, signs, and other vehicles and perceiving a non-reflective object in your path.
  • Monitor and adjust driving speeds when traveling on unlit roads at night to allow enough time to detect, react, and stop the vehicle in order to avoid striking a pedestrian, animal, or object in the roadway.
  • If your car's headlamp lenses are anything but crystal clear, have them restored or replaced to improve light output.

AAA engages in research, surveys and a significant amount of automotive testing on new and emerging vehicle technologies to help educate the driving public and keep the roadways safe. Previous research in this area includes the use of high beam versus low beam (U.S. only) and the impact of deteriorated headlights on nighttime visibility.

About AAA Colorado

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