Imagine you’re driving along a road and you approach a bridge. you notice a sign that reads, “bridge freezes before road.” why do bridges become covered with ice before roads do? research this question and respond in depth, writing a full paragraph. be sure to include examples. at the end of your response, provide at least two authoritative sources that you used in your research.

Bridge freeze before road because of two reasons:

1. Bridge are exposed to environment from all sides. That is why they are more prone to temperature decrease. While roads are only exposed fro top, they are least prone to the environment as compare to bridges.

2. Bridge have more surface area for heat loss. While, road have lesser area available for heat loss.

Sources:

https://wonderopolis.org/wonder/why-do-bridges-freeze-before-roads

http://wxguys.ssec.wisc.edu/2011/02/28/why-do-bridges-ice-before-the-road/

http://icyroadsafety.com/icybridges.shtml

Bridges are exposed to more environmental factors than typical roadways are. This is because the roads are built on top of the ground, leaving typical road exposure only on the surface and what very little part of the side is raised higher than the ground and therefore exposed. Bridges are exposed to the elements from all sides. They are also typically built over wet areas, increasing their exposure to the elements through “sea breezes.” They are not subject to any geothermal heating that typical roadways are exposed to. The earth under normal road ways absorbs heat and warm ups, then release heat which keeps the ground warm for a while. Bridges do not have this type of insulation. When freezing rain falls over a roadway and a bridge at the same time, the bridge is the same temperature as the air and is prone to freezing almost as quickly as the rain. Environmental factors from the surrounding area under the bridge can also cause the bridge to freeze more quickly. Fog, mist, and cooler temperature from the surrounding water lower the temperature of the bridge. Metal also cools down faster than tar itself. They are prone to temperature decreases simply because they have more surface area for heat loss. Typical roadways are less prone to this type of cooling or this amount of cooling.  

Sources:

http://icyroadsafety.com/icybridges.shtml

https://science.howstuffworks.com/nature/climate-weather/atmospheric/question566.htm

Explanation: