To satisfy your thoughts, the Bunching got worse when the clever people in Brussels stepped in & reduced the HGVs to 56MPH from the acceptable 60MPH, coaches removed from the outside lane to increase the chaos in the centre lane, a lot of HGVs are very powerful, Eg/Volvo's / scanias / Mans / Mercs, but there are a lot underpowered for the load they are pulling " Mainly British Built HGVs" the practice of Bunching is Dangerous, stupid, reckless & unproffesional. Yes as said, if the HGV in front had to slap on you will get the knock on effect, I & many have seen it & also the crushing of the drivers legs but the worst, the drivers life, I was never in that position as I valued my life, regards the saving fuel, the brunt of HGVs have side wind deflectors just to the side of the cab door, on the cab roof, & trailer sides, these have been designed to save fuel & also to stop children trying to get under the trailer. Just a point for you people out there that cut up a HGV, that cause of action has caused hundreds of deaths, with either the Artic Jackknifing, the load moving, or the HGV ending up on top of a car, Motorways are the safest place
in the country it's the people that don't know how to use them that's where the trouble lies.