When driving in a heavy snowstorm during the day, you should use:

Using low-beam headlights during a heavy snowstorm is the safest choice because they are specifically designed to provide adequate illumination in poor visibility conditions. Low-beam headlights create less glare compared to high-beams, which can reflect off snowflakes and limit your visibility even further. This reduced glare helps you see the road and surrounding vehicles more clearly while minimizing the risk of blinding yourself or other drivers.

In contrast, parking lights are not bright enough to help you see the road well and are mainly intended for use when the vehicle is stationary. Four-way flashers indicate that the vehicle is stopped or experiencing trouble and do not provide necessary illumination for driving. High-beam headlights can exacerbate visibility issues in snowstorms since they create more glare, making it harder to see. Therefore, utilizing low-beam headlights is essential for maintaining safety and visibility while driving in such challenging weather conditions.