I know there's a few fans of this on the forum so thought I'd give it a heads up. It seems to be a brand new series, not sure how long its been on for? Airing around 11.35 on Wednesdays. It's presented by Gethin Jones (according to Wikipedia he presented the July 2010 series, although I never saw this air?)
Thankfully they've got rid of the rather awkward and cheesy 'studio' and is now presented on the roads with each programme having an investigative theme, in this case it was fatigued HGV drivers. Tried to find it on ITV Player but it's only showing the 2009 series ITV4 repeats. I'm sure it's a new 2011 series though as they showed the unmarked HGV used by Police in Birmingham, which was featured on Midlands Today and BBC's Motorway Cops at the beginning of the year.
The CMPG Lorries were indeed on Motorway Cops.
Oh it's such a perfect day, I'm glad I spent it with you...