US Edition A further 1.5 million drivers admitted performing sudden manoeuvres or changing direction because they were following the devices' directions, while five million said they had driven the wrong way down a one-way street.
A total of 14 million drivers - half of Britain's driving population - now use satellite navigation in their cars to get them where they want to go.
But campaigners fear that the devices can often replace common sense and believe many users may be putting their lives in danger as a result.
One in five of the 2,000 motorists polled blamed the gadget for making them hesitate on a busy road and lose track of the traffic, while more than one in 50 said it had caused or nearly caused an accident.
Recent examples of sat nav blunders include the Syrian lorry driver transporting luxury cars from Turkey to Gibraltar who ended up in Skegness because his system was confused by the Rock's status as part of the UK.
Meanwhile in Gillingham, Dorset, four actors from a touring theatre company had to be rescued from the roof of their pink Mercedes van after their sat nav directed them through a flooded ford.
Maggie Game of insurance giant Direct Line, which carried out the survey, warned: "If a satnav gives you an instruction that is likely to endanger other road users, ignore it.
"Motorists must realise that while they are a helpful navigation tool, they should not follow their instructions to the detriment of road safety."