Why do bridges ice over before roadways?



Even though Tennessee has had some record-breaking high temperatures this year, winter and the ice storms it brings are not far away. According to the Federal Highway Administration, almost 25% of weather-related car accidents occur on icy, slushy or snowy roads. Sadly, nearly 117,000 Americans suffer some type of injury in crashes on slick roadways annually.

While you may encounter ice on any road or parking lot in the Volunteer State, bridges tend to ice over before roadways do. Understanding why may keep you safe during the upcoming winter.

Circulating cold air

With normal roads, cold air sits on top of warm pavement, as the ground retains heat. Even if temperatures are below freezing, comparatively warm surface temperatures prevent roadways from freezing. This is not the case with bridges, however.

Because bridges span open spaces, cold air can readily circulate above and below them. If a bridge’s temperature falls below 32 degrees, the bridge’s surface may collect ice. Even if you are driving on wet pavement before entering the bridge, your car’s tires may begin to skid on the bridge. Your car’s brakes may also not work normally.

Staying safe behind the wheel

Because bridges ice over more quickly than other stretches of road, you must pay close attention to both air temperature and weather conditions. If the ambient is near or below freezing, you may want to reduce your speed before driving over a bridge. You probably should also increase your following distance.

While you can take steps to stay safe when driving on icy roadways, other drivers may not be so careful. Ultimately, if someone’s poor driving causes you to suffer an injury on an icy bridge, you may be eligible for substantial financial compensation.