Britain has become a nation of satnav junkies, which is causing many motorists to drive dangerously, says a new report.
One in 20 drivers gets a speeding fine because of their "addiction" to satnavs, which show the wrong speed limit, according to the study.
Motorists' over-reliance on the devices led nearly one in five (18 per cent) of drivers to drive "dangerously".
Drivers said "incorrect directions" had caused them to make a U-turn or to drive the wrong way down a one-way street.
And about one in six (17 per cent) of motorists say their satnav has given them the wrong speed limit while out on the road.
The research by comparison website uSwitch concludes the UK is "a nation of satnav junkies". About 95 per cent rely on them to find their way to their destination.
The report comes ahead of higher speeding penalties coming into effect across England and Wales this week that will see fines soar.
The uSwitch report says nearly eight out of 10 (78 per cent) of drivers now use satnavs or smartphones to guide them on their journeys.
But 56 per cent say they also rely on their satnav for the correct speed limit.
Many of the latest devices have the legal road speed programmed into the satnav software, which tracks the roads and directions.
But widespread ignorance of the correct speeds on different types of roads -- combined with "over-dependence on the satnav instructions" -- means many motorists are being fined for breaking the speed limit because the information on the satnav is wrong, says the report.
More than half of drivers (56 per cent) don't know the correct speed limit on single or dual [motorways], for example.
And 58 per cent fail to upgrade their satnav regularly so key information, such as speed limits, can be out of date.
The report says drivers must "sharpen up on laws of the road and update satnavs".
It concludes: "An over-reliance on satnavs and smartphones is causing motorists to drive dangerously on Britain's roads."
New rules introduced last month say drivers must keep all handheld devices in secure holders and out of the driver's view.
But one in six (16 per cent) of drivers admitted to keeping their devices behind the steering wheel, on the passenger seat or even next to the gear stick, risking a heavy fine.
Rod Jones, insurance expert at uSwitch, said: "We are officially a nation of satnav junkies, but our addiction to technology is causing us to drive dangerously and risk large fines.
"While satnavs and smartphones are an incredibly useful tool for motorists, it is important to remember they are never a complete substitute for knowing the rules of the road."
Studies have found that drivers "switch off" parts of their brain when the devices are on.
Motorists have also been directed by satnavs into fields, and trucks have become stuck after being sent down village lanes.
-Daily Mail