Drivers have been caught using mobile phones and even watching Netflix on an iPad by a covert police lorry.
Almost 40 driving offences were detected during Devon and Cornwall Police's crackdown on dangerous driving.
Operation Tramline saw police officers team up with National Highways and use an unmarked lorry cab to spot commercial driving offences.
The lorry – which is surrounded by cameras and even has police lights fitted – gives officers an elevated view, allowing them to see into the cabs and driver seats of larger vehicles.
Officers used the lorry to patrol routes across Devon and Cornwall, including the A38 and M5, and also to capture video footage of any offences.
Over the course of the one-week operation, the team stopped 52 vehicles and detected 38 offences.
It included seven drivers using mobile phones, six driving without insurance, two people driving under the influence of drugs or alcohol and four scaffolding vehicles which were reported for being overweight and in a dangerous condition.
They also stopped one motorist who supplied false details – but was then identified through fingerprints and found to be disqualified from driving.
Superintendent Adrian Leisk, who is the strategic roads policing lead and chair of the Vision Zero South West enforcement sub-group, said: “The new mobile phone laws mean that the moment you pick up and use your phone while driving – for whatever reason – you have committed an offence.
“Using your phone behind the wheel of a car is dangerous, but when you add the sheer size and weight of an HGV, the outcome is amplified. We have seen horrific outcomes relating to distracted HGV drivers.
“Anyone caught using their phone can expect a fine and penalty points. For some professional drivers, this could result in losing their livelihood. It’s just not worth it – put your phone somewhere out of sight and out of reach.”
The HGV operation was first trialled in 2015 with one HGV tractor cab and capturing over 5,000 offences. Since March 2018 National Highways have funded three HGV tractor units for police forces to use with one in the North, Midlands and South.
Between the launch of Operation Tramline in July 2015 and April 2022 more than 28,100 offences have been recorded. The most common offences were not wearing a seatbelt (8,375) and using a mobile phone (7,163).