The UK government has announced that there will be an independent research exercise into glare from vehicle headlamps [1].
The Department for Transport (DfT) is a ministerial department of the UK Government responsible for the English transport network [2]. They are supported by twenty-four agencies and public bodies [3]. The DfT has said [4] that the research will allow us to “better understand the root causes of driver glare and identify any further appropriate mitigations”.
The announcement comes in response to numerous complaints from drivers, who feel the problem is becoming worse.
Figure 1: Glare from car headlamps. [9]
What has Changed
Glare from car headlamps is, of course, not a new problem. Anyone who has driven at night has likely experienced some level of discomfort from other car headlamps, most often when the other driver leaves their high beams on for too long! However, potential reasons that the issue could be getting worse may include:
- Increased use of LEDs rather than incandescent bulbs for car headlamps.
- Badly aligned headlamps.
- More vehicles with headlamps at a greater height, such that the beam is directly in view.
Of these, the increased use of LEDs or other technology changes to the headlamps seem the most likely culprit if the issue is in fact getting worse.
What is Already in Place
Vehicle headlamps are, according to the UK government’s response to one of the petitions, “designed and tested to … ensure that they are bright enough to illuminate the road but don’t affect the vision of other road users”.
In addition, the DfT has advised that April of last year saw a UN agreement to amend headlamp aiming rules, which are expected to come into effect in 2027. These rules relate to correcting headlamp aim based on weight loaded into the vehicle.
Accidents Caused by Glare
The Guardian reports that the UK government figures show that 280 collisions per year in Britain have dazzling headlights as a contributing factor. Of these, six involved someone passing away. The extent to which the contribution of headlamp glare contributed to the collisions and their effects is of course difficult to quantify.
For context, it was reported [5] in 2016 that, since 2010, there had been around 28 road deaths per year due to glare from direct sunlight.
The government’s response to the petition referenced above states that “We know that lots of people raise concerns about headlight glare – but also that the police collision statistics don’t show any underlying road safety issue.” Interpret that as you will…
Potential Further Mitigation
It is not clear what further mitigation measures the DfT or the government in general would consider applying. We have considered some potential options for this, we will leave it to the reader to decide how likely or how effective these would be:
- Adopting more stringent restrictions around acceptable intensity for headlamps.
- More enforcement of current rules such as increased checks regarding headlamp alignment and other compliance.
- Promulgation of more information regarding the issue.
- Specific measures at high-risk locations such as layout changes, introduction of further traffic measures, reduced speed limits etc.
- Increased road lighting to reduce the contrast when headlamps become visible.
Glare Impacts in Other Contexts
Glare impacts are relevant in many other areas of life in the UK and elsewhere in the world. Some examples include:
- Direct sunlight glare in homes and offices: This is often considered a nuisance and can require mitigation, sometimes in the form of visors, blinds or coating for windows. This would usually only be a formal requirement in a workplace. In a private residence, mitigation is usually undertaken to improve comfort at home.
- Reflected sunlight from solar panels or glass façades: This is a big topic that is not covered fully here. We have written extensively with regard to impacts from solar panels, and produced a freely available guidance document on how to manage this issue. This is often something that developers of new solar and building projects must consider, particularly with respect to road users, private dwellings, airports and railway lines. The issue can require mitigation, often this needs to be agreed prior to a developer receiving consent for a project.
- Glare from artificial light sources: This can be a nuisance (e.g. bright light towards a private residence), or a safety hazard (e.g. towards a vehicle). Aviation interests in particular are carefully safeguarded against impacts of artificial light. This includes guidance documents from the Civil Aviation Authority around lights that can cause distraction and confusion [6] and also formal legislation such as the Air Navigation Order [7] and the Laser Misuse (Vehicles) Act 2018 [8] which prohibit certain dangerous use of artificial lighting in the UK.
The level of legislation, guidance and mitigation requirements for glare impacts in general is quite variable. Glare impacts, whether from natural or artificial sources, cannot be eliminated entirely, and the extent to which impacts are significant is in some cases debatable. Nevertheless, the trend in the UK seems to be towards increased levels of concern over the issue in various contexts, so the issue is likely here to stay.
The outcome of the UK government’s investigation remains to be seen. It will be interesting to see whether any actions are taken in regard to headlamp glare concerns.
About Pager Power
Pager Power has been supporting renewable energy and building developers for over 20 years. We are the leading provider of glint and glare assessments, most often for solar panels and building façade. Sometimes developers are required to undertake such modelling for car windscreens in proposed car parks as well, particularly around airports or busy roads. If your project is facing potential glare issues, please do not hesitate to get in touch.
References
[1] Rawlinson, K (April 2024), UK government launches review into headlight glare after drivers’ complaints (link), last accessed April 2024, The Guardian
[2] gov.uk (undated), DfT About Us (link), last accessed April 2024, UK Government
[3] gov.uk (undated), DfT Home (link), last accessed April 2024, UK Government
[4] Petitions, UK Government and Parliament (undated), government response to petition (link), last accessed April 2024, Petitions, UK Government and Parliament
[5] Start Rescue (March 2016), Sun glare risk to UK motorists: How to stay safe (link), last accessed April 2024, Start Rescue
[6] E.g. UK CAA publications CAP 168 (link) and CAP 736 (link), last accessed April 2024E.g. UK CAA publications CAP 168 (link) and CAP 736 (link), last accessed April 2024
[7] UK Government (2016), The Air Navigation Order 2016 (link), last accessed April 2024, UK Government
[8] UK Government (2018), Laser Misuse (Vehicles) Act 2018 (link), last accessed April 2024, UK Government
[9] Dave Goudreau (May 2020) from Unsplash.com. Last accessed 15th April 2024. Available at: https://unsplash.com/photos/black-bmw-m-3-on-road-during-sunset-zIVkC_6tcEo
