UK drivers are being urged to check their sunglasses before getting behind the wheel, amid warnings that some lenses could leave motorists unknowingly on the wrong side of the law. The concern, raised by the RAC, centers on the darkest sunglasses, which can reduce vision too much for safe driving and potentially lead to legal consequences.

The RAC explains that the key measure for sunglasses is Visible Light Transmission (VLT) – how much daylight the lens lets through. Lenses at the very top end of the tint scale, often labelled 'category 4' on the packaging, allow in only a tiny amount of light. This can make it harder to judge hazards, spot other road users, and react in time, especially when light levels suddenly drop, such as during heavy rain or an unexpected storm.

Legal Framework and Highway Code

The RAC points to Section 96 of the Road Traffic Act 1988, which makes it illegal to drive if your eyesight doesn't meet the legal standard. If your vision is impaired – including by overly dark sunglasses – you could face penalties such as a fine and three points. The organisation also notes that while sunglasses are useful for cutting glare in bright weather, the darkest styles can compromise safety.

In addition, Highway Code Rule 94 advises motorists not to use tinted glasses, lenses, or visors at night, and to take care in poor visibility if eyewear restricts what drivers can see. In practice, if sunglasses affect your ability to see hazards or road users, it could be viewed as careless driving – and in serious circumstances, dangerous driving. The Daily Record's coverage emphasised that an accident could seriously worsen a driver's position if unsuitable eyewear is a contributing factor.

Recommendations from the RAC

According to the RAC, category 3 sunglasses are generally the safest choice for daytime driving because they offer strong sun protection without being excessively dark. The RAC adds that category two, although not as dark, are also considered a good option for daytime driving, providing a good balance between glare protection and visibility.

However, the RAC warns that even these categories should not be worn at night or in low-light conditions. Category 1 lenses are lighter, suitable for weaker sunlight, and are legal to wear while driving in the day, but they provide limited glare protection.

AA Guidance on Sunglasses Standards

The AA advises that all sunglasses should carry the CE mark and meet the European Standard BS EN 1836:2005. The AA also recommends a good quality anti-reflection coating, a hard coating to protect lenses from scratches, and warns that sunglasses with deep side arms are not recommended for driving.

The AA notes that if you're involved in a crash and unsuitable eyewear is considered a contributing factor, you could face prosecution. This underscores the importance of choosing sunglasses that meet safety standards and do not impair vision.

Highway Code Requirements for Sunglasses

The Highway Code sets out specific requirements for sunglasses while driving:

  • Sunglasses must not have any scratches or external damage that makes it difficult for you to see.
  • Sunglasses must not be tinted while driving at night or in otherwise poor visibility.
  • Sunglasses must not be so dark that they stop you from seeing clearly.
  • Sunglasses must not make it difficult for you to see traffic signals clearly.

These requirements are designed to ensure that eyewear does not compromise a driver's ability to see the road, other vehicles, pedestrians, and traffic signals.

Conclusion

As the summer sun continues to shine, drivers are reminded to check their sunglasses before setting off. Choosing the right category of lens, ensuring they meet recognised standards, and avoiding overly dark tints can help keep you safe and on the right side of the law. The RAC and AA both stress that while sunglasses are essential for comfort and safety in bright conditions, they must never impair your vision to the point where you cannot drive safely.