Why is the road surface of a bridge potentially more dangerous in winter?

The correct answer highlights that bridges are particularly susceptible to the formation of ice during winter conditions. Unlike regular roadways that have the benefit of heat retention from the ground below, bridges are elevated and exposed to colder air on both the top and bottom surfaces. This means that they cool down more rapidly than solid road surfaces, making them prone to freezing before other areas are affected. Consequently, drivers may encounter icy conditions on a bridge even when other roads appear to be clear, increasing the risk of slipping and losing control of a vehicle.

Other options may suggest factors like maintenance issues or differences in construction material, but these do not address the core reason behind the increased danger on bridges specifically during winter weather. The traffic levels on bridges are not inherently linked to the road surface conditions either; thus, those factors do not contribute to the unique hazards that icy bridges present.