The force announced on Wednesday it had first deployed the lorry last month as part of an undercover trial to enable officers to look into other vehicles from above.
It follows the introduction of a similar initiative by police in England and Wales seven years ago, which has been used in more than 30 counties.
The surprise development comes after Police Scotland told The Scotsman in 2020 that it had “no plans” to follow suit.
One motoring group said the unit should focus on lorry drivers because their vehicles had the potential to cause the most harm.
Police Scotland said since Operation Tramline was launched two weeks ago, 36 drivers had been reported for a total of 85 offences, which also included not wearing seatbelts and speeding.
The offences included 47 for using mobile phones.
Those caught include a 23-year-old woman eating a bowl of cereal in the outside lane of the M90 while driving southbound over the Queensferry Crossing.
She was fined £100 and had three penalty points added to her licence.
Road policing officer Tom Aitken said: “We wouldn’t see that if we weren’t in the unmarked truck with the elevated position looking down on those vehicles.”
A lorry driver on the Edinburgh City Bypass was fined £200 and given six penalty points for steering with his forearms while he had both hands on his mobile.
Police said he was “clearly not in control of his vehicle”.
The force unveiled its new vehicle in South Queensferry on Wednesday.
Constable Aitken said: “We are always looking at ways to enhance our ability to investigate road traffic offences.
“The HGV enables officers to have a good view of drivers and what they are doing.
“It is another tool we are using to make Scotland’s roads safer.”
"It is just not smart eating as you are driving, it is downright dangerous.
“The same goes for using any mobile device and reading.
"Acting like this means you are distracted and therefore not in proper control of your vehicle.
"A split second lapse in concentration could result in a crash. Not wearing a seatbelt is life-threatening.”
Neil Greig, the Scotland-based policy and research director of motoring group IAM RoadSmart, said: “Operation Tramline has been a big success south of the Border, so it is encouraging to see Police Scotland now using this approach.
"In our view, it is best targeted at other heavy goods vehicle drivers, who can do the most damage if they are not concentrating on their driving by, for example, watching movies or using handheld phones.
"With a system now being proposed in Scotland for the official use of dashcam footage for prosecutions, and also this operation, some drivers might feel a bit persecuted.
"However, if you are driving safely and legally, you will have nothing to fear and getting the worst drivers off Scotland’s roads can only be a win-win for safer roads.”