Largely agreed on trailers.

Re: electrified overland cargo. I'm not fully current on details, but my understandings are that:

- High range usually occurs at low speed and over carefully-selected (e.g., flat) routes. There was a bus range-record set a while back which involved a stripped empty bus running at about 20 kph / 13 mph constant speed. Problem being of course that this is almost the precise opposite of a typical operation cycle especially for urban transit. Commute transit (with its dual morning/evening cycle) or intercity (presuming reasonable range) might be viable. Trolly busses which draw current from fixed infrastructure remain the presently viable electrification option, though perhaps with a small onboard battery capacity to move between conductor segments.

- High-load electrified cargo seems to be based on moving loads consistently downhill while relying on electrified traction for the return, unloaded, uphill segment. I'm aware of a quarry which operates such vehicles, and proposals for lumber shipments. These are effectively gravity powered with regenerative braking and electric storage. Again, a special use case.

- I vaguely recall a European trial using an EV cargo lorry for short-haul deliveries on the order of 4--6 km, which is where my "single-digit" range comment comes from. Not turning up a reference, though I believe that was by either Volvo or BMW.

- Gross vehicle weight is a major constraint for trucking, cuts directly into revenue-generating cargo margins (literally, load that pays), and remains a critical concern for EVs. Again, private passenger vehicles which already have a poor payload/vehicle mass ratio are an easy problem to solve here, and despite that, passenger EVs run heavy compared to ICE vehicles. For either mass transit or cargo freight, where payload mass is far higher relative to vehicle mass, there's far less latitude.

- Aerodynamics are the other concern. Drag increases with the square of speed, and options are for low-profile high-mass loads (e.g., flatbeds and plate-steel or concrete barriers), or low-mass high-profile loads (consumer electronics, light bulk materials, etc.). Each run into issues with cargo.

And with all that, there's what EV-based overland non-tracked cargo competes with: rail, trolly-bus or trolly-truck designs, barge or shipping traffic (where available), etc.

In particular, there's been remarkably little R&D in the conventional rail sector best I can tell (outside high-speed rail). It seems to me that there ought to be considerable opportunity for much greater efficiencies in flexible, dynamic, trainset assembly and re-routing, which would provide for the efficienies of rail transport (energy consumption reduced by a factor of 5x or more per tonne/km) without the consequent challenges of battery-based transport. (This is presuming freight rail is electrified, itself a point in which the US is notably lagging.)

Rail is efficient in terms of energy but not flexibility. Melding that efficiency with the flexibility of last-mile delivery (or last 50-mile delivery) afforded by conventional trucks seems to me a real game-changer. It seems odd that nobody seems to be working on this. Large logistics operators (Amazon, WalMart, UPS, FedEx, possibly existing rail or trucking organisations) might be potential candidates, but again, there's nothing that I'm aware of.