Pressure from consumer groups has prompted the Department for Transport to commission a study into headlight glare. Some, including the RAC have pointed the finger at LED lighting. However, ADAS expert Neil Hilton of Core Diagnostics believes that a wider range of potential causes should be under the spotlight.
We’ve all experienced the momentary blinding effect of a bright headlight beam from an oncoming vehicle. Consumer groups have long campaigned for action to be taken on this important issue and an RAC survey of more than 2,000 motorists found that the majority are regularly getting dazzled, with one in ten saying that they now avoid driving at night for this reason.1
Of those affected, a staggering 85% said that headlight glare is a problem that’s getting worse and almost nine out of ten dazzled drivers who participated in the RAC survey think that some lights just appear much brighter. This has led many to conclude that the benefits of the relatively recent move to LED technology may be outweighed by the potential risks to road safety. There is growing speculation that the study recently commissioned by the Department of Transport may lead to an introduction of limits on the power output of LED lighting, or even legislation that forces vehicle manufacturers to revert back to halogen headlights.
The RAC’s report also raised questions over headlight alignment. Neil Hilton, Technical Sales Director for Core Diagnostics, believes that this is where more attention needs to be focused, whilst highlighting a number of issues within the service and repair sector that may be contributing to the problem.
Having spent a significant part of his career at a major OE lighting manufacturer prior to joining remote diagnostics provider Core Diagnostics, Neil knows more than most when it comes to vehicle lighting.
“The dangers of headlight glare should not be underestimated and the Government’s commitment to tackling this safety-critical issue is very welcome news” says Neil.
“LED technology and the ‘intelligent’ vehicle lighting systems that most modern passenger cars are equipped with offer enormous benefits over the headlights that vehicles had ten to fifteen years ago.
Compared to halogen lighting, the low power consumption of LEDs has enabled vehicle manufacturers to use smaller batteries and thinner gauge cabling, both of which reduce vehicle weight, which improves fuel economy and therefore lowers emissions.
The colour temperature of LED lighting is much closer to daylight than halogen bulbs too. This reduces fatigue when driving in the dark, and dynamic lighting systems also further improve visibility when cornering.
Many newer vehicles are also now equipped with Auto High Beam Assist or LED Matrix systems, which use a windscreen mounted camera to detect oncoming traffic and will automatically switch from high beam to dipped beam. In the case of LED Matrix lighting, when the camera detects an oncoming vehicle the beam pattern is reconfigured by switching individual LEDs on or off, so that the road either side of the oncoming vehicle is illuminated without the driver of the oncoming vehicle being dazzled.”
However, Neil believes that while these sophisticated systems are to be welcomed, the technology has evolved at a pace that the service and repair sector has struggled to match.
“The number of vehicles equipped with advanced LED lighting systems has been growing in recent years and accurate alignment of these headlights is a much more complex task than it used to be. This could explain why a growing number of vehicles on UK roads may have mis-aligned or uncalibrated headlights” says Neil.
“What’s more, SUVs are now the most popular style of passenger car and they typically have their headlights mounted higher than saloons or estate cars. Combined with the fact that LED lights have a wider beam pattern than halogen, this higher mounting position means that if the angle or beam of the headlight unit is out even by a relatively small amount it can easily be enough to dazzle oncoming traffic.
For these reasons, correct headlight alignment and calibration may be more important than ever but, in Neil’s view, this is something that there is little awareness of within our industry, with many technicians failing to appreciate the importance of correct headlight alignment, while others simply lack the necessary equipment.
“Many beam setters are not equipped with an inclinometer or standard target scale, which is essential to ensure the headlight beam can be accurately aligned to the vehicle manufacturer’s specifications. What’s more, whilst stricter guidelines were introduced for MOT testing stations in 2016 to tighten the band of tolerance for headlight alignment, there’s no requirement for a revised beam setter to perform an MOT test so the current standards allow too much scope for error for today’s vehicles.
The cost and availability of OE diagnostic tools can also be an issue. With many vehicle brands, replacing and aligning lighting units is only possible with the OE tool, as third-party tools typically can’t be used to programme the basic settings for lighting control units. For example, a number of Mercedes-Benz models have an ECU for each headlight unit and when new headlights are fitted, they can only be coded to the vehicle using an OE diagnostic tool before alignment and calibration can be performed.
Correct alignment of dynamic or Matrix lighting is impossible without the OE diagnostic tool. If manual adjustments are made to the angle or position of the headlight unit, the lights will automatically reset to their original position when the vehicle ignition is switched off and back on. Changing the basic setting reference point requires the lighting ECU to be put into Service mode so that a new position can be set and stored in its electronic memory.
Features like Auto High Beam Assist or Adaptive Dynamic Lighting additionally use the camera mounted in the vehicle’s windscreen to detect oncoming vehicles. If it’s not accurately calibrated, the switch from high beam to dipped beam – or reconfiguration of the beam pattern in the case of Matrix systems – will be delayed, causing oncoming drivers to be dazzled momentarily.
Most workshops and technicians are aware that the windscreen mounted cameras require precise calibration to ensure the correct operation of lane departure systems, but few are aware that this same component has a key role in ensuring that headlights operate correctly and won’t dazzle other drivers.
When multiple systems rely on the windscreen mounted camera, it’s even more critical that it is calibrated accurately to the thrust line of the vehicle, as any additional tolerance introduced at this stage could have a profound effect on the accuracy of the headlamp beam control.
With our remote diagnostic service, workshops no longer need OE diagnostic tools for programming basic settings, headlight alignment or camera calibration” says Neil.
“At Core Diagnostics we always have the latest OE diagnostic tools in-house and our IMI-accredited remote technicians can carry out remote ADAS calibrations for the majority of brands, so workshops and body shops who use our remote diagnostic service can avoid the need for costly OE equipment.”
Awareness is the first step to overcoming these issues, explains Neil: “A greater awareness in our industry of the importance of correct headlight alignment and a greater commitment to carrying out this vital procedure could help to vastly reduce instances of headlight glare, without having to impose restrictions on vehicle manufacturers in relation to light output or colour temperature.”
Neil, who was part of the Thatcham Research steering group that introduced the Insurance Industry Requirements for the Safe Repair of ADAS-equipped Vehicles (IIR) introduced in 2021, believes that similar guidance may be required for headlight adjustment and calibration.
“The IIR guidelines helped to foster a greater awareness of the importance of ADAS calibration. Headlights are just as essential for road safety and even though new rules come in to force in 2027 requiring all new cars to have mandatory automatic headlight levelling based on the weight being carried, this will not address the issue of mis-aligned headlights or windscreen cameras being out of calibration, so I think there’s a good argument for the introduction of appropriate guidelines for headlight alignment and calibration.”
For more information call Core Diagnostics on 0151 559 3940 or email sales@corediagnostics.co.uk
1 An RAC survey of 2,000 drivers found a huge nine-in-ten (89%) think at least some headlights on cars on the road today are too bright, of which three-in-ten (28%) think most are. Of the all these drivers who complain about the brightness of car headlights, some 91% say they get dazzled when driving with three-quarters (74%) saying this happens regularly. When it comes to the effects of glare on drivers, two-in-three (67%) who suffer say they have to slow down considerably until they can see clearly again, while a similar proportion (64%) believe some headlights are so bright they risk causing accidents. Five per cent of these drivers state they have nearly been involved in a collision themselves and nearly one-in-ten (7%) say they find headlight glare so bad that they avoid driving at night altogether, a figure that rises to 14% for drivers aged 65 and over.