Line of vision
Vehicle glass, glazing and line of vision.This content is for general information only. It does not, and is not intended to, provide legal or technical advice or to represent a legal interpretation of the matters it addresses.
Frequently asked questions
- Under EU type-approval regulations, all newly manufactured vehicles must have a minimum light transparency of 70% on the windscreen and front side windows.
- Under roadworthiness testing regulations, a vehicle with a light transparency of less than 65% will fail the test.
Darkening a vehicle’s windscreen more than this or increasing the size of a vehicle’s sunblock would be illegal. For further information, see NCT Testers' Manual.
- Under Roadworthiness Testing laws S.I. No 415 of 2017, a vehicle’s windscreen and front side windows must have a light transmission transparency level of at least 65% to pass the test. If a tinted sun strip comes down below the tip of the wipers, it can impair the driver’s vision and prevent them from having a clear view of the road. It also constitutes a failure item at the vehicle’s test in NCT Testers' Manual.
- Under Irish Road Traffic regulations, the driver must always have a view to the front and side of the vehicle necessary to enable them to drive safely. Heavily tinted windows present a significant safety hazard for vehicle drivers and their occupants. Visibility is greatly reduced, particularly at night-time or times of low light, and may prevent drivers from seeing other road users or pedestrians.
- A sun visor is a temporary measure to prevent strong sunlight blinding the driver. It can be folded away when not required and therefore does not restrict a driver’s view of the road during times of low light.
- A tinted sun strip remains permanently on the windscreen and if it is wide enough to come down below the top of the wipers it is considered to be in the driver’s line of the vision and therefore can restrict their view of the road especially during times of poor light. For further information, on 'Reasons for Failure' refer to NCT Testers' Manual.
Information and regulations for important vehicle components including lights, seat belts, glass and tyres.