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New Hampshire Winter Travel: Why I-93 Road Salt May Not Be Enough
Manchester, NH – New Hampshire drivers preparing to travel Interstate 93, Interstate 95 and Interstate 89 this Thanksgiving may be relying on something that cannot always keep highways safe: road salt
By Paige Sullivan · 2026-11-11T19:01:18.044Z
Manchester, NH – New Hampshire drivers preparing to travel Interstate 93, Interstate 95 and Interstate 89 this Thanksgiving may be relying on something that cannot always keep highways safe: road salt. Even freshly treated pavement can become dangerously icy when temperatures plunge, leaving motorists facing slippery conditions despite efforts to keep roads clear.
According to winter maintenance guidance from transportation agencies, traditional road salt becomes increasingly less effective as pavement temperatures approach 20 degrees Fahrenheit, with its ice melting ability declining further as temperatures fall into the teens and single digits.
That's where a common assumption about winter road safety can become dangerous.
Why Even Salted New Hampshire Highways Can Freeze Road salt isn't magic. It lowers water's freezing point, helping melt ice and reduce freezing when conditions allow.
However, as pavement temperatures drop, the melting process slows considerably. Around 20 degrees, conventional salt works much more slowly than it does near freezing. Below 15 degrees, salt alone may struggle to melt ice quickly enough to improve driving conditions.
For motorists traveling through Manchester in Hillsborough County, Concord in Merrimack County, Nashua in Hillsborough County and Portsmouth in Rockingham County, that limitation matters.
Major routes including I 93, I 95, I 89 and the Everett Turnpike can remain slippery despite treatment, especially on bridges, overpasses, shaded roads and exposed stretches where blowing snow can accumulate.
Thanksgiving Travel Could Make Conditions More Dangerous Thanksgiving falls Thursday, Nov. 26, bringing holiday travelers onto New Hampshire's busiest highways and mountain routes.
If snow, freezing rain or rapidly falling temperatures develop during the holiday period, treated roads could still become dangerously slick.
The risk can increase overnight and early in the morning, when pavement temperatures fall and moisture refreezes.
The New Hampshire Department of Transportation uses multiple winter maintenance strategies, but no treatment guarantees ice free pavement under every condition.
Before departing, drivers should check National Weather Service forecasts and New England 511 for updated road conditions.
The bottom line: A salted highway is not necessarily a safe highway. Motorists should reduce speed, increase following distances and remain alert for icy patches even when pavement appears clear.