Final answer:
Overpasses will freeze first as they lose heat more quickly, being exposed to cold air both above and below, unlike underpasses, urban roads, and high-speed highways that are insulated by the ground or retain heat from traffic.
Step-by-step explanation:
As temperatures drop below freezing, overpasses will freeze first. This happens because overpasses are exposed to the cold air from both above and below, causing them to lose heat more quickly than surfaces that are insulated by the ground such as underpasses, urban roads, and even high-speed highways. Since underpasses are surrounded by earth on several sides, they tend to hold onto heat longer, while urban roads are often warmer due to heat from traffic and possibly surrounding buildings. High-speed highways can be expansive and exposed, but they often retain heat from friction and vehicle volume better than the elevated surfaces of an overpass. Physics explains these phenomena, as heat transfer from the surface to the surrounding air causes temperatures to reach the freezing point more swiftly on exposed structures like overpasses.