When must you turn on your vehicle headlights?

Answer: B — When visibility is less than 100 metres

Turning on your vehicle headlights is crucial for ensuring your visibility and the safety of other road users. The requirement to activate your headlights when visibility is less than 100 metres helps in several important ways. First, it allows you to see the road and any potential hazards clearly in low light conditions, such as fog or heavy rain. Second, it ensures that other drivers can see you from a distance which is vital for avoiding collisions. The regulation aims to establish a clear standard for when headlights should be used, ensuring a uniform practice that enhances road safety. Conditions such as mist, rain, or nighttime can reduce visibility significantly, and having your headlights on during these times improves overall awareness by increasing your vehicle's visibility to others on the road. Considering the various visibility limitations, activating headlights at 100 metres is a practical distance that serves to balance safety with the need for clear visibility for both the driver and other road users.