5 ms·

Finally! Someone who asked and explored this question! I had this same question for years :)

Kon-Peki 5y ago
Agreed :) But I'm not quite sure I'm satisfied that this explains why they are so different. It is hard for me to believe that American semi-trucks are more fuel efficient than European ones (fuel is so much more expensive in Europe!), but this article seems to imply that they are.
- goodcanadian 5y ago
  Aerodynamic efficiency matters much more in North America as average speeds are much higher over much longer distances. Wind resistance increases with the square of speed, so it is entirely possible that American trucks are burning more fuel per mile in spite of being more aerodynamic.
- dharmab 5y ago
  Cab over is a less aerodynamic shape (it's essentially a box). Conventional designs allow more aero features.
  - kergonath 5y ago
    > Conventional designs allow more aero features. “Conventional” is such a poor label. Convention depends on the context. The conventional form factor here is cab over.
    - chrisseaton 5y ago
      Like when Americans talk about a 'full size' car they mean an over-size one in our perspective.
    - hunterb123 5y ago
      Conventional in terms of trucks overall, cabover did not come first for trucks, nor is it a conventional design. It's not uncommon for non-cabover to be referred to as conventional. GP is using the correct terminology. https://www.innomotivesolutions.com/about/blog/item/cab-over-engine-vs-conventional-truck-which-do-you-prefer https://www.innomotivesolutions.com/about/blog/item/cab-over... https://www.smart-trucking.com/cabovers-make-a-comeback/ https://www.smart-trucking.com/cabovers-make-a-comeback/ https://powertorque.com.au/cabover-vs-conventional-and-euro-vs-usa/ https://powertorque.com.au/cabover-vs-conventional-and-euro-...
      - kergonath 5y ago
        I am not saying they were wrong, just that the terminology is stupid. Convention has nothing to do with what came first.
        hunterb123 5y ago
        I'm saying your reasoning for why it's "stupid" is wrong. Non OCE is conventional and OCE isn't, plain as that.
- frosted-flakes 5y ago
  Aerodynamics.
- bpodgursky 5y ago
  Fuel is more expensive, but not more expensive than trimming 8 feet off of the trailer (and reducing hauling capacity).
- 1123581321 5y ago
  I don't believe the US trucks have more efficient engines (yet--this is changing due to new EPA standards.) They just haul more, which is a more efficient use of expensive drivers in addition to making the most of the engine's fuel consumption.
  - Kon-Peki 5y ago
    I appreciate that explanation, thanks
  - eMSF 5y ago
    > They just haul more Not really, they are just longer. For example the US interstates have a rather strict total weight limit (even by European standards) of 36 tonnes. Where I live, the general legal limit is 76 tonnes, and there are specific (every-day) routes with vehicles weighing over 100 tonnes. Granted, such heavy trucks with special permits are longer than the 18.75 metres mentioned in the article, but even then you wouldn't want to make them any longer by wasting space for an overlong cab.
    - renewiltord 5y ago
      Weight, the longer wheelbase US trucks haul less total tonnage than the shorter wheelbase EU trucks purely due to regulations? Or are you talking about rare cases that hit the limit? Because I would never have suspected that.
    - 1123581321 5y ago
      Interesting; thank you. It looks like the federal limit in the US is 40 tons; some states are higher and others are lower. EU appears to mostly limit to 44 tons. Extensive freight rail in the US precludes much of the need for special high-tonnage routes, though you’ll see unusual items transported on trailers with extra axles from time to time.

Agreed :) But I'm not quite sure I'm satisfied that this explains why they are so different. It is hard for me to believe that American semi-trucks are more fuel efficient than European ones (fuel is so much more expensive in Europe!), but this article seems to imply that they are.

goodcanadian 5y ago
Aerodynamic efficiency matters much more in North America as average speeds are much higher over much longer distances. Wind resistance increases with the square of speed, so it is entirely possible that American trucks are burning more fuel per mile in spite of being more aerodynamic.
dharmab 5y ago
Cab over is a less aerodynamic shape (it's essentially a box). Conventional designs allow more aero features.
- kergonath 5y ago
  > Conventional designs allow more aero features. “Conventional” is such a poor label. Convention depends on the context. The conventional form factor here is cab over.
  - chrisseaton 5y ago
    Like when Americans talk about a 'full size' car they mean an over-size one in our perspective.
  - hunterb123 5y ago
    Conventional in terms of trucks overall, cabover did not come first for trucks, nor is it a conventional design. It's not uncommon for non-cabover to be referred to as conventional. GP is using the correct terminology. https://www.innomotivesolutions.com/about/blog/item/cab-over-engine-vs-conventional-truck-which-do-you-prefer https://www.innomotivesolutions.com/about/blog/item/cab-over... https://www.smart-trucking.com/cabovers-make-a-comeback/ https://www.smart-trucking.com/cabovers-make-a-comeback/ https://powertorque.com.au/cabover-vs-conventional-and-euro-vs-usa/ https://powertorque.com.au/cabover-vs-conventional-and-euro-...
    - kergonath 5y ago
      I am not saying they were wrong, just that the terminology is stupid. Convention has nothing to do with what came first.
      - hunterb123 5y ago
        I'm saying your reasoning for why it's "stupid" is wrong. Non OCE is conventional and OCE isn't, plain as that.
frosted-flakes 5y ago
Aerodynamics.
bpodgursky 5y ago
Fuel is more expensive, but not more expensive than trimming 8 feet off of the trailer (and reducing hauling capacity).
1123581321 5y ago
I don't believe the US trucks have more efficient engines (yet--this is changing due to new EPA standards.) They just haul more, which is a more efficient use of expensive drivers in addition to making the most of the engine's fuel consumption.
- Kon-Peki 5y ago
  I appreciate that explanation, thanks
- eMSF 5y ago
  > They just haul more Not really, they are just longer. For example the US interstates have a rather strict total weight limit (even by European standards) of 36 tonnes. Where I live, the general legal limit is 76 tonnes, and there are specific (every-day) routes with vehicles weighing over 100 tonnes. Granted, such heavy trucks with special permits are longer than the 18.75 metres mentioned in the article, but even then you wouldn't want to make them any longer by wasting space for an overlong cab.
  - renewiltord 5y ago
    Weight, the longer wheelbase US trucks haul less total tonnage than the shorter wheelbase EU trucks purely due to regulations? Or are you talking about rare cases that hit the limit? Because I would never have suspected that.
  - 1123581321 5y ago
    Interesting; thank you. It looks like the federal limit in the US is 40 tons; some states are higher and others are lower. EU appears to mostly limit to 44 tons. Extensive freight rail in the US precludes much of the need for special high-tonnage routes, though you’ll see unusual items transported on trailers with extra axles from time to time.