Spoken like someone that's never driven any of them - particularly the "maxodyne" ! "Singles" can pull as much freight as any other design, but DOT weight regs demand "axles/ton".
I HAVE driven em.
In fact, to quote the old Lowell George song:
"I've driven every kinda rig that's ever been made, even drove the back roads so I wouldn't get weighed."
The reason multi-axle regulations exist are pretty simple to figure out. One of those reasons keeps trucks from landing in people's front yards, because when you have that many tons riding on a single axle and something breaks, things get messy.
Another is because when you have multiple axles pulling, you have more rubber on the road. That's a no brainer.
Another is because a single axle concentrates more weight on a smaller footprint, and that does more damage to road surfaces, bridges etc. Spreading the weight across multiple footprints lessens the pounds per square inch on the road surface.
Good God...this is Trucking 101!
