A new technical report from the Transport Research Laboratory (TRL) has added to the growing public concern about dazzling headlights.

It has revealed measurable on-road effects from modern headlamps and confirms that glare is a widespread problem for UK drivers.

Seeing the light

The study, commissioned by the Department for Transport and combining instrumented vehicle measurements with a national driver survey, found that nearly all motorists report being distracted or dazzled by oncoming lighting.

It identified LED lights and higher-mounted lamps on tall vehicles as major, significant contributors to the issue. 

TRL’s research builds on earlier surveys from RAC and other groups that have repeatedly shown motorists perceive headlight brightness as worsening.

Recent polling cited in the report indicates that a large majority of drivers feel that some headlights are “too bright,” with many stating they now avoid night driving due to glare.

Vulnerable groups, especially older drivers whose eyes take longer to recover after glare, were singled out as particularly affected. 

Dangerous dynamics

Why does this issue and report matter for safety?

TRL’s fieldwork links reported glare to measurable reductions in drivers’ visual performance.

For instance, increased recovery time after exposure and temporary loss of visual detail can translate into delayed reactions when navigating hazards or adjusting speed.

Government and road-safety bodies point to existing crash data showing dozens to a few hundred collisions each year in which dazzling lights are a contributory factor.

Previous analyses have estimated approximately 250–280 collisions annually in Great Britain, where headlight dazzling was a contributing factor, including a small number of fatal incidents. 

Technical and complex

Industry and safety experts say the causes are complex.

The shift from halogen to brighter, “whiter” LED lighting, the rise of SUVs with higher lamp positions, poor headlamp alignment, and illegal retrofits are all implicated.

TRL’s report applied machine-learning analysis to pinpoint variables associated with high scene luminance and reported glare, reinforcing that vehicle design, lamp technology and mounting height interact with road geometry and driver age to produce problematic glare. 

These findings have prompted the Department for Transport to accelerate its review of headlight glare as part of the wider Road Safety Strategy.

Officials have said the TRL evidence will inform whether to push for changes to international vehicle lighting regulations, tighten enforcement on illegal bulbs and retrofits, and consider measures such as mandatory automatic headlamp levelling, which is already due to be strengthened in international rules.

Some international updates, including requirements for automatic levelling on new cars, are scheduled to take effect in the coming years, a development that could be mirrored in UK policy. 

In the headlights

Campaigners and professional bodies have welcomed the report but warned that regulation alone won’t solve the problem.

The College of Optometrists urged a combination of industry design changes, stronger enforcement, public guidance (such as correct aiming and maintenance) and targeted support for older drivers.

Road-safety groups want driver training and awareness campaigns to include the risk of dazzling and practical mitigation steps.

TRL’s work provides what many stakeholders had argued was missing: independent, empirical evidence linking modern headlamp technologies to measurable glare effects and driver impairment.

The government’s next steps, from enforcement drives to potential regulatory changes, will be closely watched by manufacturers, fleet operators, and motorists alike as the UK seeks to balance the safety benefits of improved forward illumination with the growing hazards of dazzling glare.