CDL Class A Practice Test

Using low-beam headlights is mandatory in conditions such as fog, rain, or snow because these weather elements can significantly reduce visibility. High beams can create glare and reflect off moisture in the air, making it even harder to see. Low-beam headlights provide adequate illumination for the road immediately in front of the vehicle without causing excessive glare for yourself or other drivers. This enhances safety for not only the driver but also for other road users by allowing better visibility in challenging conditions. In contrast, using low beams during daylight hours, in urban areas at night, or solely when driving over 55 mph may improve visibility, but these conditions do not necessarily require it as a matter of safety or regulation. Therefore, the focus on low-beam use in adverse weather is a crucial safety measure.