This scanner can scan thousands of license plates per minute?? Let's do the math.
The vehicle has cameras on both sides. Assuming each camera can capture plates from up to 3 lanes of traffic, to achieve "thousands" of scans per minute, conservatively interpreted as at least 2000 scans per minute, each camera would have to pull in 1000 scans per minute, or 333 scans per minute per lane. This translates to a little over 5.5 scans per second per lane, or 0.2 seconds per scan per lane. This is impossible with the recommended 2 second minimum following distance between cars, regardless of the speed the cars are traveling -- in fact, the scan rate is 10x larger than the safe carrying capacity of 3 lanes on each side of the car.. Therefore, to scan "thousands" of plates per minute, this vehicle would have to be parked in the middle of a road 10x as wide, for roughly a total of 60 lanes.
The only alternative to this would be to scan cars parked close together on both sides as the scan-van travels really, really fast up the middle. You'd have to pass 5.55 cars per second on each side. Assuming the cars are parked 5.5 meters apart, you have to travel 70mph past the line of parked cars to hit this rate, which would be not only illegal in a zone lined on both sides with parked cars, but it would also be dangerous. Maybe that's where they get the number from though? (Also, this is probably not workable due to motion blur at those speeds...)