California Driver License (DMV) Written Practice Test

At dusk is the correct time to turn on your vehicle's headlights. This is because during this time, the natural light starts to decrease and visibility can be reduced. Additionally, turning on your headlights at dusk ensures that you are visible to other drivers on the road. Options A, C, and D are incorrect because they do not accurately reflect the appropriate time to turn on your headlights. Option A suggests turning on your headlights based solely on a specific amount of time after sunset, rather than taking into account the actual visibility on the road. Option C may be a good indication to turn on your headlights, but it does not take into consideration the changing light conditions. Option D is incorrect because turning on your headlights during the day can be distracting to other drivers and use unnecessary energy.