I agree, though there are buses and trucks in those panels, and I'd hazard a guess that if the national fleet of vehicles went electric, the gross weight limits might get bumped up a touch.

If I'm remembering right the United States federal limit is 80,000 gross, but there's also a per axle specification. If electric long haulers started becoming more common, I could see the limits being bumped for the whole vehicle, while adding an extra axle or some such.