Let's assume that the fuel economy of an autonomous semi truck is comparable to that of a regular semi truck. supposedly the average fuel economy is 5.9 mpg which is honestly better than I thought it would be. For a trip from Seattle to Miami that's a 49 hour trip according to Google Maps which adds up to 3305 miles. That only adds up to 560 gallons of diesel which sounds like a lot, but look at the existing fuel tanks on a semi truck. Those things are massive. 150 gallons per side isn't uncommon for long haul trucking. Adding enough fuel to go nonstop from Seattle to Miami only adds 260 gallons of fuel which at 7lbs per gallon for diesel means 1,820 lbs. The maximum weight for a typical semi is 80,000 lbs so that's still only 2.3% of the weight that could otherwise go to cargo. But one thing to keep in mind is that without having to cater to a driver you can remove most of the weight of the cab. There's no need for a dashboard, heater core, air conditioning, steering wheel, seats, windows, doors, giant empty space on top for the driver, etc.
It would not surprise me if even with all of the extra fuel (which wouldn't even really be realistic because no one has a route from Seattle to Miami) if the weight difference was a wash between the two. At the very least so long as it can be loaded with fuel at the origin and destination it's not really a concern.
It would not surprise me if even with all of the extra fuel (which wouldn't even really be realistic because no one has a route from Seattle to Miami) if the weight difference was a wash between the two. At the very least so long as it can be loaded with fuel at the origin and destination it's not really a concern.