Severe-weather warnings would not stop half of all motorists, says the Highways Agency, although most would take the time to check out travel conditions.
At the same time, a third would not carry out any checks on their vehicles before setting out on their journeys.
As winter approaches, the agency is urging motorists to be prepared for severe weather: not just snow and ice, but strong winds, heavy rain and thick fog.
Said Derek Turner, network operations director for the Highways Agency: "Working closely with specialist forecasters from the Met Office, the Highways Agency plays an essential role during the winter months by tackling snow and ice, and warning drivers of severe weather.
"We recognise that travel can be essential and our survey shows that people do head out during severe weather, but being caught out by cold weather, strong winds or heavy rain isn't nice, especially if you've broken down.
"Drivers need to be prepared with a severe weather kit in their vehicles by carrying out simple vehicle checks before they set out, planning their journeys using our website, listening to DAB digital Traffic Radio and local radio stations, or by calling our information line (08457 50 40 30)."
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