Professional trucker here!
Elon Musk in his presentation omitted one of the most important information about the truck: How much does it weigh?
I've seen some articles wrongly stating that the truck is capable of hauling a 80000lbs (~37 ton) payload. This is wrong. This number is the maximum allowed gross vehicle weight for public roads, ie the combined weigh of the truck, trailer and payload.
In most European countries, the maximum gross vehicle weight is 40 tons. Typically, a diesel truck weighs around 8 to 9 tons and another 8 to 9 tons for the trailer. This is 16-18 tons for the tractor-trailer combination, so this leaves 22 to 24 tons for useful payload.
It is inevitable that the Tesla truck will be heavier due to the weigh of the batteries. The 100KWh Tesla S battery weighs around 500 kilos. If the truck has a 1MWh battery, then the extra weight should be around 5 tons.
Some analysts believe that they won't use the Tesla S cells, but the powerwall storage cells which have better cycling characteristics, but worse energy density. So the battery pack could be well over 5 tons.
Effectively, this truck will have a 20-25% less useful payload compared to a diesel truck.
Also there were some weird and false claims in that presentation. For example it was claimed that even the best diesel tractors fully laden can only do 45mph over a 5% incline, while the Tesla can do 65mph. In Europe semi truck speed is electronically limited to 90Km/h (56mph) and the best tractors (Scania R730 or Volvo FH16 750) have no problem maintaining that speed over a 5% incline.
BTW this is what happens when you accelerate hard a powerful diesel truck (this is probably 60 tons or more)
Another weird claim is that windscreens crack on average once a year. Excluding dump trucks working on mines and quarrys (lots of rocks getting flinged around) I am not aware of trucks used on paved roads having their windshield cracked with that regularity.
Also they claim 1 million miles without breakdowns. Judging from all the problems they had so far with reliability issues, replacing hundreds of defective Drive Units, sometimes twice or thrice on the same car, I can't take that claim seriously.