A lethal 1,500 metre stretch of black ice sent cars spinning off the road early this morning.
At least five motorists lost control on the A4136, on the Gloucester side of Mitcheldean.
Police attended the scene at about 5.25am after three cars came off the road in quick succession.
Officers warned others to take extreme caution but a spokesman said at least two more drivers, that the force was made aware of, came unstuck.
A Vauxhall Corsa, Kia, and Vauxhall Astra all crashed there but no-one was seriously hurt.