Drivers have been warned by the RAC that wearing overly dark sunglasses while driving could break the law. The alert comes as the UK experiences its fourth summer heatwave.
Sunglasses rated at the highest level on the Visible Light Transmission scale, specifically category four, let in only a very small percentage of daylight and can impair vision while driving. This category can be found on the label of the packaging.
Under Section 96 of the Road Traffic Act 1988, it is an offence to drive if eyesight falls below the required legal standard, which could result in a fine and three penalty points. This applies when overly dark sunglasses compromise vision.
Highway Code advice on tinted glasses
Rule 94 of the Highway Code advises against using tinted glasses, lenses, or visors at night or in poor visibility if they limit vision. If wearing sunglasses reduces a driver's ability to spot hazards, it could amount to careless or even dangerous driving in serious cases.
Category three sunglasses are recommended as the best option for daytime driving, offering sun protection without being too dark. Category two also provides a good balance between glare protection and visibility but should not be worn at night. Category one sunglasses are legal for daytime driving but offer only modest glare reduction.
RAC policy officer Harriet Hernando said: “Most of us will be reaching for our sunglasses this week, but many will not realise that the darkest of shades could be unsuitable for driving, and even illegal in the case of category four sunglasses.” She urged drivers to check their sunglasses, especially if used for extremely bright conditions like high-altitude environments, warning they could impair vision and lead to a fine and penalty points.
