OK, maybe they are speeding a little. But basically, they're out there trying.
At the same time, hundreds of thousands of trucks are also on the road. I don't mean to pick on trucks unnecessarily. They can't help it that they are large and heavy and block the view of signs. I don't expect them to be quiet or dainty.
They can, however, behave better than they do. After just driving 17 hours this weekend, seven of them on the nightmare that is I-81, I think I've figured out why trucks behave badly. They think they're cars! They whisk in and out of lanes at 75 miles an hour. They merge with gleeful abandon. They give way reluctantly and with a great screech of downshifting gears. Sometimes they travel in tandem, tying up both the travel and the passing lanes while dozens of cars fume behind them.
Trucks should act like trucks. They should plod along at a speed that befits their tonnage. They should give way more generously than they do. And they should let cars ... be cars.