How is fuel consumption per mile 5x but fuel burn per hour 10x?
The Physics and Economics of Moving 44 Tonnes at 56mph
31–40 of 123 posts
Re: The Physics and Economics of Moving 44 Tonnes at 56mph
#32For people that want to make the calculation: A truck does not need a 15 ton battery. In Europe, we have mandatory breaks for truck drivers. So you need a battery pack for max 400km of range, let's say 500km. When you have a break, you charge. For this, you need like 1500kWh battery pack, which weigths like ... wait, 15 tons. But this is not entirely correct, the real values reported are between 120-150Kwh/100km, tha…
It’s weird that he’s so in the numbers but then doesn’t carry through with the battery electric truck calculations. He just dismisses it out of hand.
Your cargo may be reduced but your fuel costs will also be reduced. It’s quite a complicated calculation.
Are you hauling sand? Then you probably can’t spare a single kg of cargo limit. Doing LTL work? Then maybe you’re not totally filled anyways. It really depends. If you’re fine with a 35 ton limit you might be able to make good money with the fuel savings.
Re: The Physics and Economics of Moving 44 Tonnes at 56mph
#33Re: The Physics and Economics of Moving 44 Tonnes at 56mph
#34> At 0.5 mph differential, the overtake takes 291 seconds — over a minute of blocking the outside lane. Annoying, but it gains the driver 5.0 extra miles across a working day. The driver gets there 5 minutes earlier in exchange for causing a 7-km tailback multiple times per day? That seems like exactly the kind of thing that should be regulated away: the truck in front is limited to 90 km/h, you're limited to 90 km/h…
> That seems like exactly the kind of thing that should be regulated away This is regulated via "no overtaking by trucks" [1] signs on portions of road that are susceptible to formation of queues, or more dangerous road conditions. P.S. To bundle some replies: > but they only apply during busy hours Don't remember ever seeing the time interval next to these signs. They are tied more to the location than the time. But…
Ahh, the power of defaults.
Does it (still) make sense for this to be "default allow?" Why not have the trucking industry lobby for every Truck Overtaking zone, instead of making residents lobby for the opposite?
Re: The Physics and Economics of Moving 44 Tonnes at 56mph
#35> At 0.5 mph differential, the overtake takes 291 seconds — over a minute of blocking the outside lane. Annoying, but it gains the driver 5.0 extra miles across a working day. The driver gets there 5 minutes earlier in exchange for causing a 7-km tailback multiple times per day? That seems like exactly the kind of thing that should be regulated away: the truck in front is limited to 90 km/h, you're limited to 90 km/h…
From a commercial perspective, you would think the fuel savings from slipstreaming would more than make up for those five minutes.
There's a diffuse, but I suspect large, economic cost to delaying other vehicles.
Re: The Physics and Economics of Moving 44 Tonnes at 56mph
#36great article but the 44 tonne limit is not "physics", it is regulation. if an electric truck would be allowed to weigh 5 tonnes more all these calculations would be different.
The regulation is at least partially informed by physics though.
Braking distances, road damage (scales with the fourth power of axle weight), bridge limits, etc.
If the limit could safely and appropriately be 49 tons for diesel trucks right now, it probably would be.
Re: The Physics and Economics of Moving 44 Tonnes at 56mph
#37> The five minutes of inconvenience to you saves them meaningful time and money over the course of a day.
Assuming my time and everyone else stuck behind them combined is far less valuable than the truck driver.
Re: The Physics and Economics of Moving 44 Tonnes at 56mph
#38I was reading the NASA truck aerodynamics thread earlier and realised that commercial freight is one of those fields that touches everyone's daily life (everything you own arrived on a truck) but sits in a complete knowledge blindspot for most people. I work in fleet fuel efficiency and wrote up the foundational mental model, covering why trucks weigh what they weigh, why they're all doing exactly 56mph, why diesel i…
Do you have an RSS feed for your blog?
Re: The Physics and Economics of Moving 44 Tonnes at 56mph
#39Argh the liberal admixture of different units (mpg, kg, L, hr) in the first table really brings home that this is a UK piece.
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Re: The Physics and Economics of Moving 44 Tonnes at 56mph
#40I was reading the NASA truck aerodynamics thread earlier and realised that commercial freight is one of those fields that touches everyone's daily life (everything you own arrived on a truck) but sits in a complete knowledge blindspot for most people. I work in fleet fuel efficiency and wrote up the foundational mental model, covering why trucks weigh what they weigh, why they're all doing exactly 56mph, why diesel i…
this is well written. thank you - you broke down the economics nicely. I do think maybe with a hub & spoke model - big trucks move loads to hubs -- then smaller electrified trucks cover the less than 200 miles from hub to spoke. electrified smaller trucks and vans are already economical today. you get to benefit from using diesel for long haul routes - while also - better economics on the electrified front i.e a hybr…
The cost to load/unload a truck becomes the main expense if you move it too many times.
This is why LTL shipments can be a significant fraction of just sending an entire container, and that's assuming they're still palletized.