When temperatures drop, which structure tends to freeze before road surfaces?

• A. Roads
• B. Bridges
• C. Intersections
• D. Tunnels

Answer: (B)

Bridges tend to freeze before road surfaces because they are elevated and exposed to cold air on both the top and bottom. Since there’s no earth underneath to provide warmth, the bridge deck loses heat quickly to the surrounding air, especially with wind chill, so it reaches freezing temperatures sooner. Roads sit on the ground, which can store and slowly release heat from the earth and sun, helping to keep the surface from freezing as quickly. Tunnels are sheltered environments that can stay warmer or less windy, and typical road sections receive more heat from the ground, so they’re less likely to ice up before bridges. This combination makes bridge decks the first to ice in cold conditions, creating a surprising hazard for drivers.