Blinded by the Light

By: Richard C. Moakes, CEng

Now that we are in the winter months, the majority of people leave work as daylight diminishes and arrive home in the dark.  During the commute many of us experience at least one brief moment of being blinded by the glare of oncoming headlights.  Thankfully, these brief encounters do not usually result in a collision or accident.  For drivers who live in states with rolling hills, such as Pennsylvania, a blinding experience can occur when the oncoming vehicle crests a hill.  The offending vehicle doesn’t need to have the headlights in the high beam position for this to occur because even in the low beam position the headlight beam can still be a visual hindrance to oncoming traffic because of the uphill gradient of the road before the crest of the hill.

According to the National Safety Council, nighttime driving is the most dangerous time to drive.  Americans only do 25% of their driving at night and yet 50% of our traffic deaths occur after dark.  This is a result of several factors, but the potential role of overly bright headlights should not be ignored.  Even with high beam headlights on, visibility is limited to about 500 feet (250 feet for normal headlights) which creates less time for the driver to react to something in the road, especially when driving at higher speeds.

The brightness of vehicle lighting has been increasing ever since the invention of the horseless carriage.  From the 1950s to the 1980s, vehicles were equipped with sealed-beam headlights, which were replaced by halogen headlights in the 1980s and 1990s.  By the late 1990s and early 2000s, high intensity discharge lights appeared on high-end manufacturers models.  These lights caused a bright glow that was compatible to the spectrum of daylight.  This technology was the start of the really expensive headlight replacement bill, in the event of a fender-bender or headlight failure.  The popularity of high-intensity discharge lights diminished when the Light Emitting Diode (LED) headlights appeared on vehicles around 2010.  LED lights are longer lasting and more energy efficient than previous generations of headlights and can be arranged to produce different shapes and patterns to suit the styling of the vehicle.  In general LED lights have a greater concentration of light that makes the headlights appear brighter.  The output spectrum of LEDs tends to have a more blueish tint, which is more uncomfortable to the eye than the warm or yellowish light from the old sealed-beam or halogen bulb.

Federal regulation of headlight size, shape, luminance, and the number of lights allowed on the front of the vehicle has occurred over the years from 1939 to present to enhance the safety of nighttime driving.  However, the federal government has not addressed a major factor in present day trends that makes nighttime driving more hazardous.  This is the trend of pickup trucks and SUVs becoming bulkier and higher off the ground, and the permitted adjustment of ride height of the vehicle, which can vary from state to state.  Unlike the situation of the vehicle producing a brief blinding glare as it crests a hill, a large pick-up truck or large SUV such as a Nissan Titan, a Chevrolet Suburban, a Chrysler Aspen, or a Ford Expedition can cause a blinding glare as it sits across the other side of an intersection at a red light.  Federal laws permit these vehicles’ manufacturers to mount the headlights as high as 54 inches above the ground.  Manufacturers position the headlights at this maximum height of 54 inches to compliment the present body styling of the pickup truck.  The high mounting of the headlamps and the tall front grills promotes the aggressive, tough image of the vehicle.  However, this does not help the majority of road users who are sitting in a medium size SUV, minivan, or sedan with an eye-level height between 49 and 54 inches.  Admittedly, with the headlights in a low beam position, the pickup truck or large SUV across the intersection at the redlight shines its light beam below the height of 49 to 54 inches at the point where the sedan is sitting.  However, if the high beams are left on or the offending vehicle is sitting on a slight slope, the effect can be blinding.

There is a glimmer of hope on the horizon to improve the headlight glare situation.  The federal government is allowing manufacturers to install a very expensive solution to solve the problem that the automobile industry and the government have created.  This is what is known as Adaptive Driving Beams (ADBs).  The proposed rule by the National Highway Traffic Safety Administration (NHTSA) on October 12, 2018, offered amendments to Federal Motor Vehicle Safety Standards (FMVSS) No. 108 lamps, reflective devices, and associated equipment, to permit the certification of adaptive driving beam headlighting systems, if the manufacturer chooses to equip vehicles with these systems.

What are ADBs?  ADBs are an advanced high-tech lighting system made up of many individual, very bright, LEDs.  However, the brightness of each LED can be precisely controlled which in theory makes ADB headlights special.  When sensors detect other cars, software responds by dimming the LEDS – but only the ones that project onto those vehicles.  Meanwhile, the LEDs that aren’t shining on the other vehicles maintain full brightness.  Each LED adjusts dynamically to the position of other vehicles, and in this way, there is bright illumination around the vehicle, but less on the vehicles.  Operation of ADB headlights can be thought of as illuminating what is ahead, but projecting “shadow” on other cars to minimize dazzling their drivers.  As smart and as high-tech as ADBs are, up to now they have not been offered in the US, and that is because FMVSS No. 108 mandates that cars sold in the US must have distinct low beam and high beam patterns.  ADB headlights dynamically adapt their pattern and don’t meet that requirement.

So, here’s what to do to combat the darkness and the glare from LED and high intensity discharge headlights from the present generation of vehicles on the road:

• Aim your headlights correctly, and make sure that they are clean.
• Dim your dashboard.
• Look away from oncoming lights.
• If you wear glasses, make sure that they are anti-reflective.
• Clean the windshield to eliminate streaks.
• Slow down to compensate for limited visibility and reduce stopping time.
• If you find that you are blinded, concentrate on the white fog line to your right and follow that until the glare has gone.

However, today’s brighter headlights do offer the vehicle operator an improved nighttime site distance over the former headlight designs.  But now there is a need to tackle the hazards that come with this newer technology. Contact us if you are in need of an accident reconstruction expert for an incident involving headlights.