Motorists are being warned of a very dangerous stretch of black ice near to Ranks Corner on the A4136 at Mitcheldean.
Police closed the road for a while to allow gritters to do their work.
It has since reopened but motorists are being urged to avoid the road if at all possible.
Gloucestershire Police have also asked motorists to be aware that due to the cold weather, many of the county's roads could be badly frozen with very slippery surfaces.
This is particularly the case on minor roads and roads out of built up areas.
The dangerous roads come as temperatures plummeted across the county overnight to a low of -3.5C.
But from 3pm today temperatures will rise to 6C with dowpours of rain.
Overnight temperatures should remain at about 3C.