Are headlights too bright? Everything you need to know about headlight glare

Headlight glare (or headlight dazzle) describes when the main lights fitted to a vehicle dazzle other road users, a phenomenon that is most likely to be experienced at night. 

RAC research indicates some headlights do cause glare. In the most recent research released in January 2024, nine-in-10 drivers (89%) surveyed said they find at least some car headlights too bright. This may be from dipped headlights, and/or headlights that are on full/main beam.

Yes, figures from the RAC suggest the problem of dazzling headlights is getting worse. As many as eight-in-10 drivers (85%) surveyed who say they are affected by headlight glare believe the problem is getting worse.

At best, headlight glare is an annoyance and makes driving uncomfortable and more difficult - this is referred to as 'discomfort glare'. But the consequences can be more severe. Two-thirds of drivers affected by glare who were surveyed by the RAC said they have to slow down considerably because dazzle stops them seeing clearly. And seven per cent said they find dazzle such a problem that they have given up driving at night.

The RAC understands there may be a number of reasons why drivers suffer from headlight glare. It’s also likely to be the case that different perceive and react to dazzle to different extents.

Firstly, it may be down to the alignment of the headlight. If it is angled incorrectly, it is more likely to dazzle other people. If in any doubt, get your vehicle checked by a good quality garage. Data shows that of the 32.4m MOT tests carried out in 2022 on Class 4 vehicles in the UK – which includes cars – as many as 1.6m failed due to misaligned headlights.

Newer lighting technologies, with the increase in vehicles fitted with full LED headlight systems, may also help explain the increase. This is because the human eye reacts to LED lights in a different way to more ‘yellower’ halogen beams that can cast a more diffuse light. What’s more, cheap aftermarket LED bulbs – which are not road legal in the UK – may also be being increasingly fitted by drivers replacing their car headlight bulbs, and contributing to the problem.

The increasing prevalence of vehicles that sit higher on the roads – typically SUVs (sport utility vehicles) may also be a factor, with drivers who are in cars that sit lower on the road more likely to be adversely affected. RAC research shows that six-in-10 drivers (62%) of conventional cars blame the dazzling on higher vehicles, whereas only 35% of those in higher vehicles point the finger at similarly sized vehicles.

RAC research shows drivers are split on the causes of glare. Given the complexity of the topic, the RAC called on the Government to commission independent research to understand the true reasons for headlight glare, and to work out what can be done. In positive news for drivers, this call was heeded in 2024.

Highway Code Rule 114 states drivers MUST NOT:

• use any lights in a way which would dazzle or cause discomfort to other road users, including pedestrians, cyclists and horse riders
• use front or rear fog lights unless visibility is seriously reduced. You MUST switch them off when visibility improves to avoid dazzling other road users (see Rule 226).

It also states that in stationary queues of traffic, drivers should apply the parking brake and, once the following traffic has stopped, take their foot off the footbrake to deactivate the vehicle brake lights. This will minimise glare to road users behind until the traffic moves again.

The worst ‘must not’ indicates it is backed up by law, in this case the Road Vehicles Lighting Regulations 1989.

Headlights on all new vehicles sold in the UK have to pass a rigorous ‘type approval’ process before they are permitted for use.

Yes, the alignment of headlights alone is checked at the MOT. However, the RAC is aware that alignment is a part of the test that some garages can find more difficult.

Since 2013, there has been an average of 280 collisions a year where dazzling headlights were a contributory factor. However, it’s worth noting that these collisions are only those where a police officer attending the scene can be sure that headlight dazzle was a factor.

What’s more, just because there aren’t collisions caused by dazzling lights doesn’t mean there isn’t a problem. If drivers are feeling less safe and less confident as a result of them, or if they’ve reduced the amount they drive (or even stopped driving) as a result of glare, this suggests there is a problem.

No, it’s not. Additional research from other motoring organisations elsewhere in Europe, including the FIA, ADAC in Germany and ANWB in the Netherlands, backs up the RAC’s figures that highlight the genuine concern a lot of drivers have.

The RAC first raised the issue of headlight glare with the UK Government in 2018. Since then, it has commissioned a series of pieces of research to highlight the extent of the problem, and the impact it is having on drivers. It works closely with other organisations that have an interest in headlight glare, including the College of Optometrists and IAM RoadSmart. The RAC also contributes its findings to European and international groups that are also examining the topic.

Yes. In 2024, the work of the RAC and its partners on this campaign was successful in getting the Government to commission its own independent research into headlight glare. TRL, the Berkshire-based company running the project, is completing on-road testing as well as scientific review, during the winter of 2024-25. The UK Government will then consider its recommendations, likely summer 2025.

RAC senior policy officer Rod Dennis said: “The fact the Government has listened to drivers’ concerns and heeded our calls to examine the complex issue of headlight glare in more detail marks a real turning point. The topic has undoubtedly struck a chord with motorists up and down the country, with many people contacting us directly to call for something to be done.

“Brighter headlights, while giving drivers a better view of the road ahead, are clearly causing other road users significant problems. As many as nine-in-10 drivers tell us they believe at least some car headlights are too bright, while 14% of drivers aged 65+ say they have stopped driving altogether as a result of being dazzled.

“An independent study provides a golden opportunity for the Government and industry to get to the bottom of the problem, identify the factors involved and map out a way forward. We’re aware of regulatory changes being made at an international level that will hopefully make a difference in many years to come, but are concerned that these alone may not be enough to address headlight dazzle.”

Baroness Dianne Hayter, who has worked with the RAC to campaign on this issue, said: “This is a victory for all those drivers affected by glare who’ve complained to their MP, signed the parliamentary petition, or indeed sought help from an optometrist – only to discover the problem was with headlights, and not their eyes. This is an issue the RAC has long campaigned on and I am delighted the Government has recognised there is a real problem. We look forward to discussing its research in due course.”

Mike Bowen, Director of Knowledge and Research at the College of Optometrists, said: “The results from research by the RAC are helpful to inform our understanding of how changes in vehicle headlight technologies may be affecting both the functional vision of young and older drivers, and their visual comfort, when driving at night. Older drivers are likely to be disproportionately affected by headlight glare, so may be more likely to experience difficulties or to decide not to drive at night at all.”

The College of Optometrists, which the RAC works closely with on this topic, recommends the following top five tips to help make it easier when driving at night:

• Keep your windscreen clean and smudge-free to reduce the impact of glare
• If you wear glasses, ensure they’re clean and smudge-free too
• Stay up to date with sight tests with your local optometrist to ensure your glasses help you see as well as possible when driving and your eyes are healthy.
• When presented with bright oncoming headlights, keep your eyes open and cast your eyes to look at the curb or side of the road. This will keep you safe and help minimise the effect of adaptive and discomfort glare.
• Finally, be considerate when driving and dip your headlights when required. If you have automatically dimming headlamps, remember they don’t always pick up oncoming cars, cyclists and pedestrians, so know how to dip them manually.

In addition, adjust your rear view mirror at night to reduce the effect of bright headlights behind you. Newer cars have self-dimming mirrors that can also help, although you may notice you still experience unavoidable glare through your wing mirrors.

If you are dazzled while driving it’s important to safely slow down, or even stop your vehicle until your vision improves. 

The irony of dazzling headlights is that in many cases drivers won’t be aware of how they themselves may be partly the cause of the problem – most likely through no fault of their own.

It’s important to ensure your headlights are angled correctly, according to the load you are carrying. That’s because a car with rear passengers and a fully loaded boot will naturally cause the front of the car to be positioned slightly higher on the road, compared to a car that just has the driver in it. Check your car handbook for how to align the lights, and adjust accordingly. Some newer cars adjust headlights automatically based on the load carried.

If you regularly get flashed by other drivers at night, it may be because they perceive your headlights to be too bright. This could be something you talk to a good quality garage about, either as part of the MOT or at another time.

Are you affected by headlight glare? If you have a story to tell, please share it in the comments below.