One police force has already instructed its staff to remove all such systems from its vehicles.
The concerns, raised at the Fleet News Hit for Six conference last week, stem from what interpretation to place on a 21-year-old law - The Road Vehicles (Construction and Use) Act 1986 – which states that vehicles must provide a clear view of the road ahead.
Ray Adkins, head of transport at Northamptonshire Police, explained that while the issue was still being investigated, the force had taken the precautionary decision to remove objects such as sat-nav systems.
“We have said that these must not be fitted in any of our vehicles,” he explained.
“The legislation says the swept area of the windscreen must be kept clear.”
Mr Adkins advised fleet operators concerned about the legality of sat-nav systems and any other potential obstructing items fitted to the screens of their vehicles to carry out a risk assessment for each vehicle.
The consequences, he pointed out, could be very serious.
“If a child steps out from behind a parked car and the driver’s view is obstructed by the system or any other item, the driver may not see the child as quickly, may brake later and the injury to the child may be worse.”
Chief Superintendent John Millar, of Northants Police, said that while his force had removed their sat-nav systems, they would take an ‘advisory approach’ with members of the public.
“Drivers using satellite navigation systems incorrectly are not a significant contributor to casualty statistics,” he said.
“But drivers should always make sure they put the satellite navigation systems in positions that do not impair their ability to drive or obstruct their view.”
His view was echoed by senior solicitor and specialist road traffic and regulatory lawyer Philip Somarakis, who said: “While the regulations are clear that it is the responsibility of the user to ensure that there is a full, clear view of the road ahead, what we are saying is that motorists should take a commonsense view of the regulations.
“If motorists are sensible about where they place their sat-nav in the screen, they should not encounter problems.”
The new Highway Code, which was published last week, also contains a reference to new technology: “There is a danger of driver distraction being caused by in-vehicle systems such as satellite navigation systems,” it warns.