The regulations state that visors must allow a minimum level of light transmission, typically 50% or more, to ensure adequate visibility for the rider. This means that heavily mirrored or excessively tinted visors that significantly reduce light transmission are generally not permitted.
If a motorcyclist has a genuine medical reason for wearing a tinted visor, they may be exempt from the requirement. To qualify for an exemption, a motorcyclist should obtain a medical certificate or document from a qualified medical professional stating the necessity of using a tinted visor.
It's important to note that regulations and requirements may change over time, so it's recommended to consult the most up-to-date and official sources for accurate information. To find more information about the current law regarding mirrored or tinted visors for motorbike helmets in the UK, you can visit the official website of the UK government's Department for Transport (DfT) or the official website of the Driver and Vehicle Standards Agency (DVSA). These sources should provide the most reliable and up-to-date information on motorcycle helmet regulations and requirements in the UK.