What specific requirements must a vehicle's headlamp beam meet to pass an MOT test, and how should these requirements be checked?

To pass an MOT test, a vehicle's headlamp beam must meet specific requirements to ensure optimal visibility and safety on the road. The primary focus is on the alignment of the headlamps to provide a proper aim for the light beam. This check should be performed without altering any control settings if the vehicle is equipped with driver's beam aim controls. For vehicles with hydro-pneumatic suspension systems, it is essential to have the engine running during this inspection, as the system may require power to function correctly.

The test aims to verify that the headlamps are aimed according to the manufacturer's specifications, ensuring a uniform and focused light distribution on the road ahead. This alignment is crucial for safe driving, especially in low-light conditions or at night. During the MOT test, an inspector will manually adjust the headlamps to check their aim, ensuring they direct light onto the designated area without causing glare for oncoming drivers.

To perform this check, the inspector will typically use a light meter or a similar tool to measure the intensity and distribution of the light beam. The process involves adjusting the headlamp's height and angle until the desired output is achieved, as indicated by the vehicle manufacturer's guidelines. This manual adjustment process ensures that the headlamps are properly aligned and meet the required standards for road safety.