Because they weigh upwards of 20 tonnes... They're also banned from Lane 3. I don't know whereabouts in the country you are, but if you're down here in the South you'll no doubt have noticed that people aren't the best at moving over when they are moving more slowly than in the inner lanes.
Usually on my ride home, the lanes on the motorway are completely reversed with Lane 3 at an almost standstill.
But regardless, HGV's with a governor set to 56 overtaking an HGV with its governor set to 55 are a source of annoyance for a great many people on the roads. If you now have to factor in the Riverside Sparkle or whatever it was called overtaking both HGV's at 60, then a tailback a short distance behind will be the likely result as the following traffic starts slowing from 70/80 to 60 and then progressively breaking as people move around, and braking slightly harder than the car in front till a mile or so back cars are coming to a stop.
That's where traffic jams come from.
Biting the hand that feeds IT
