Why Do Bridges Freeze Before Roads? (5 Reasons Why)

Have you ever heard about bridges freezing before roads? You probably are if you’re used to checking for icy spots and black ice when crossing a bridge or an overpass because you live in a cold environment.

Nevertheless, why are some regions more prone to ice than other roads? Look what we found out about bridges that freeze before the road!

Why Do Bridges Freeze Before Roads?

1. Bridges Cannot Trap Heat

A bridge is losing heat from every side as the icy wind hits it from above, below, and on both sides. As a result, heat is simply evaporating off the road’s surface.

Therefore, heat beneath the road maintains its warmth sufficiently to prevent ice even when the roadway temperature decreases and the air temperature falls beyond freezing.

In comparison, bridge structures cannot store any heat. Thus, they will continuously lose heat and eventually freeze whenever the air temperature reaches the freezing point.

So, no matter how hot bridges or overpasses become, they will eventually freeze once the temperature drops as they don’t have any ability to trap heat for a long time.

2. Bridges Have Easy Access To Cold Air

Simple access to cold air is the scientific explanation for why bridges and overpasses ice before other highways.

Bridges are far more exposed to wind. As a result, the air from above and the air moving underneath it will lose all the heat the bridges got from the warm weather.

That said, this makes it possible for the bridge to release heat more quickly, become colder more quickly, and ice over more quickly.

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3. Exposure To Different Types Of Elements

Exposure To Different Types Of Elements

Bridges freeze before roadways for three main reasons. First, they have nothing below them to protect them from the arctic cold, the primary and most prevalent cause.

Second, a bridge has no defense against the wind and bad weather since the underside is exposed.

Third, the earth, which serves as an insulator all through bad weather, is used to build a roadway.

Even though it may be freezing outside, the ground is warm underground, acting as insulation. Bridges will rapidly freeze because they are all exposed to different outside elements.

4. Depending On The Location Of The Bridge

A bridge’s location is another factor in why it freezes so quickly. Yes, bridges are entirely exposed, but what matters is what’s underneath.

In many situations, bridges span rivers, streams, and other bodies of water. As a result, water immediately freezes, leaving frigid areas.

Therefore, the bridge is more vulnerable to freezing due to these cold patches than a road without them.

5. How Bridges Are Constructed

Because of how bridges are built, they freeze first before the road. Metal is known as a heat conductor, and most bridges are made of metal.

Although there is heat inside the bridge, it swiftly escapes to the ground, colliding with the frigid air every time the temperature drops.

Of course, the air temperature can affect the warm air to freeze fast if the outside climate is 32°C or lower, resulting in ice patches on the road.

In addition, concrete and asphalt, the materials used to make roads, are poor heat conductors.

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Because the materials prevent it from passing through the blacktop, whatever heat is present in the ground remains below.

Further, too many individuals believe they can cross a bridge without problems since the roads are clean.

However, these enormous structures may have slippery areas even when the roads are clear.

To know more, you can also read our posts on why people steal cars, why there are toll roads, and why your concrete driveway is lifting.


The premise is that bridges and overpasses will closely track the air temperature. A bridge’s base will go below freezing if the air temperature drops below zero.

As a result, snow or rain will freeze and adhere to the bridge. Therefore, it’s essential for drivers to know that the bridge can be dangerous even if the road appears fine.

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