Simple satnav instructions like "turn left" and "carry on, you're doing very well" are easy enough for us to comprehend while driving, but anything more complex and we lose focus, start to swerve around the road and our little brains simply can't cope with the flood of data.
The news comes from researchers at the University of London's Royal Holloway college. Their test plonked some volunteers in front of a driving simulation, then fed them more and more complex satnav instructions, finding that drivers lost concentration, increased their speed and even got worse at spotting pedestrians when their satnavs were overloading them with more complex directions and information about roundabout exits.
However, using a satnav is still safer than trying to unfold an Ordnance Survey map on your lap at 82mph, so don't worry about it too much. [BBC]