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I have always wondered why those trailers with the super low floors are not more popular... They look to be more aerodynamic, they can hold more stuff, and the

I have always wondered why those trailers with the super low floors are not more popular... They look to be more aerodynamic, they can hold more stuff, and they would prevent the problems presented in the article. Maybe does it have to do with the fact that loading docks are already high, and this would make the loading process more cumbersome? I am not sure...

bombcar 3y ago
It's the loading dock. The vast vast majority of trucks are not filled to the brim (and even if they're at their weight limit, they often have "air" in the box). "Lowboys" are mainly used for large construction equipment where they need the extra height. A semi-trailer is a surprisingly cheap piece of equipment. Some trucks that are special purpose use the lower areas (see https://www.mayflower.com https://www.mayflower.com for an example; household movers have more weight capacity than space).
- KennyBlanken 3y ago
  Retrofitting loading docks to work with lower-floor vehicles would be trivial, not to mention many buildings that could not accept deliveries would be able to.
  - kelnos 3y ago
    If the trucking industry didn't want to spend $127 per trailer to add underride protection, I doubt building owners will want to spend what is likely to be several thousand dollars or more on retrofitting their loading docks.
  - bombcar 3y ago
    You’d potentially have to load from the side. Probably more effective to move the trailer wheels to the far back of the trailer.
    - HankB99 3y ago
      That presents problems navigating tight corners where tractor trailers already have difficulty. I see some trailers where the position of the wheels can be adjusted. I wonder if that is for weight distribution or for the roads planned to be driven.
PrivateButts 3y ago
Not a trucker, but I believe it's because trailers with lower ground clearance will bottom out if you aren't careful with your route planning. Things like rail crossing with aggressive approach and departure angles would be pretty risky with a low to the ground trailer.
thedrbrian 3y ago
the other problem is tyres. we use super singles on our trucks and the tractors, trailers and rigids have the same size tyre. 385/65 R22.5 to have a flat floor on the trailer with the smaller tyres you've now got to stock another size of tyre or run dual tyres on the trailer.
jandrese 3y ago
Loading docks are built to one specific height. If your trailer is low you will have to lift every package out of the trailer and onto the dock.
elihu 3y ago
It's probably mostly standardization, I'd guess. I think a more sensible design would be to have the middle of the trailer low to the ground with a floor hump above the rear wheel well and the front where it hitches on to the truck, but that would make loading and unloading awkward. One could imagine having a side door instead of or in addition to a back door, and a lower loading dock. I get that a rectanglar storage compartment is easier to deal with in a lot of ways, but it just seems ridiculous to have a box riding four feet off the ground, with the wheels causing as much atmospheric drag as they possibly can. This seems like a solution you'd arrive at if you think energy is practically free, and wasting energy has no consequence. It also seems unnecessarily top-heavy, in addition to the safety problems mentioned in the article (and the underride guards proposed to mitigate the safety issue would most likely create even more wind resistance).
Ekaros 3y ago
Tires are certain height. You want a flat floor. And you want to maximise the surface area and the volume. As such only sensible option is to build above tires and for the full width. Thus the room in between.

bombcar 3y ago

It's the loading dock. The vast vast majority of trucks are not filled to the brim (and even if they're at their weight limit, they often have "air" in the box). "Lowboys" are mainly used for large construction equipment where they need the extra height. A semi-trailer is a surprisingly cheap piece of equipment. Some trucks that are special purpose use the lower areas (see https://www.mayflower.com https://www.mayflower.com for an example; household movers have more weight capacity than space).

KennyBlanken 3y ago
Retrofitting loading docks to work with lower-floor vehicles would be trivial, not to mention many buildings that could not accept deliveries would be able to.
- kelnos 3y ago
  If the trucking industry didn't want to spend $127 per trailer to add underride protection, I doubt building owners will want to spend what is likely to be several thousand dollars or more on retrofitting their loading docks.
- bombcar 3y ago
  You’d potentially have to load from the side. Probably more effective to move the trailer wheels to the far back of the trailer.
  - HankB99 3y ago
    That presents problems navigating tight corners where tractor trailers already have difficulty. I see some trailers where the position of the wheels can be adjusted. I wonder if that is for weight distribution or for the roads planned to be driven.

PrivateButts 3y ago

Not a trucker, but I believe it's because trailers with lower ground clearance will bottom out if you aren't careful with your route planning. Things like rail crossing with aggressive approach and departure angles would be pretty risky with a low to the ground trailer.

thedrbrian 3y ago

the other problem is tyres. we use super singles on our trucks and the tractors, trailers and rigids have the same size tyre. 385/65 R22.5 to have a flat floor on the trailer with the smaller tyres you've now got to stock another size of tyre or run dual tyres on the trailer.

jandrese 3y ago

Loading docks are built to one specific height. If your trailer is low you will have to lift every package out of the trailer and onto the dock.

elihu 3y ago

It's probably mostly standardization, I'd guess. I think a more sensible design would be to have the middle of the trailer low to the ground with a floor hump above the rear wheel well and the front where it hitches on to the truck, but that would make loading and unloading awkward. One could imagine having a side door instead of or in addition to a back door, and a lower loading dock. I get that a rectanglar storage compartment is easier to deal with in a lot of ways, but it just seems ridiculous to have a box riding four feet off the ground, with the wheels causing as much atmospheric drag as they possibly can. This seems like a solution you'd arrive at if you think energy is practically free, and wasting energy has no consequence. It also seems unnecessarily top-heavy, in addition to the safety problems mentioned in the article (and the underride guards proposed to mitigate the safety issue would most likely create even more wind resistance).

Ekaros 3y ago

Tires are certain height. You want a flat floor. And you want to maximise the surface area and the volume. As such only sensible option is to build above tires and for the full width. Thus the room in between.