Harrisburg, PA – As snow and subfreezing temperatures sweep across Pennsylvania this month, state officials are warning drivers in Harrisburg, Pittsburgh, and Philadelphia to be alert for black ice forming on bridges and overpasses before it appears on main roads.
According to the National Weather Service (NWS), bridges freeze first because they are exposed to cold air both above and below. That air circulation draws warmth out of the concrete and asphalt much faster than from roads connected to the ground, which retain residual heat longer.
“Even when your dashboard shows 34°F, bridges can already be icy,” the NWS said Friday. “That’s when black ice forms — thin, nearly invisible layers that make driving conditions extremely dangerous.”
The Pennsylvania Department of Transportation (PennDOT) will pre-treat bridges and elevated sections of I-76, I-80, and I-81, especially around river crossings and hilly areas prone to sudden temperature drops. Officials are urging motorists to slow down before reaching bridges, avoid sharp braking, and maintain a consistent speed over icy spans.
PennDOT also advises drivers to give plow and salt trucks extra space, as road crews continue working through the weekend to manage snow and freezing drizzle expected to move eastward from western Pennsylvania into the Philadelphia region.
Motorists can monitor live updates via 511PA.com and follow @PennDOTNews for regional alerts.
