> 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, you should expect to travel in convoy with that truck even through manufacturing tolerances mean your limiter is actually set to 90.5.
If the 0.5 km/h is actually valuable to the trucking industry, they can invest in more precise limiters at scale.
> 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.
Does it still make sense for that to be "default allow?" Why doesn't the trucking industry lobby for every Truck Overtaking zone, instead of making residents lobby for the opposite?
> This isn’t advisory. It’s a physical limiter in the engine’s ECU. The truck cannot go faster.
I live in Latvia (in the EU) and see a significant part of our ARTICs on the roads go well past 90km/h daily. I presume their fleets do monitor the speed and alert the driver if speeding for a prolonged period of time but they are obviously not physically limited. Maybe the limits do come from the factory but get disabled? I really couldn't say.
A recent journalistic investigation uncovered a problem with the weight limit not being followed on a mass scale too. Specifically by our lumber industry whos drivers are incentivized to break the law. Even if you see a dangerous overloaded truck on the road and call the Police, it is likely no action will be taken because there only a couple of units in the country that are equipped to weigh a freight truck out in the field.
Probably the first thing to consider is the trucks have their speed calibrated periodically to ensure the accuracy of their tachographs (in the UK at least) so a truck doing 90kmph may show as 100kmph+ in a passenger car, I know my Volvo is 7% out, and my Seat is closer to 10% out.
That said, depending on the truck, there's fuses you can pull, ECU remaps and even for the older trucks with the magnetic sensor in the gearbox, the trick is/was to stick a magnet on the sensor (with a bit of string, so you can pull it off remotely if you get pulled over). All of these methods are becoming less feasible, as things like the aggregate wheel speed sensors used for ABS get used, you can't just fool one thing now.
As for the weight limit problem, that's a whole other rabbit hole!
>Most assume the truck driver is being inconsiderate.
You could probably add a whole section of specifically learning to drive a car with trucks on the road to driver education programs and it would do wonders for traffic.
>Anti-idle ordinances exist in several US states and EU regulation is moving in this direction.
Yep, grab a sleeping bag or take your clothes off and use evaporation cooling on yourself. The good news is that car/van camping stuff can apply to trucking as well and that is fairly popular these days.
Another option is simply having places to sleep outside of the truck that are powered by solar/wind and don't cost anything to truckers, but that's only viable when we actually care about reducing emissions over profit.
>Every kilogram you add to the vehicle is a kilogram you can’t carry as freight.
You can save a bunch of weight by not having the sleeper cab if you can readily stop somewhere for a safe place to sleep. There's quite a bit of frontier savings you can do by externalizing costs of transporting stuff to other industries (aforementioned free hotel rooms) and getting tax payers to pay for it, which makes a ton of sense here since trucks are transporting all of the food we eat.
I 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 is so hard to replace, and why 1% fuel savings matters when you're burning 43,000 litres a year.
This is the first in a series, there's already a 2-part deep dive on hydrogen up as well. Tried to keep it accessible without dumbing it down.
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 hybrid model
A very well written article! I'd add a few things though.
> Every kilogram you add to the vehicle is a kilogram you can’t carry as freight.
That is only relevant when hauling bulk loads, think ore, soil and the likes, or you're carrying a trailer full of IBC liquid containers. I worked in stage lighting stuff, our trailers were at least 3/4 foam by volume, they didn't even come close to maxing out their weight.
> A battery pack storing equivalent energy would weigh on the order of 16 tonnes at current lithium-ion energy densities.
You don't need to haul a fully equivalent battery. Drivers have to have their mandatory rest breaks of 30+15 minutes here in Germany - that's enough to charge 300-400km of range. Additionally, they can be charged at loading docks, provided the freight base or the customer have chargers set up.
> For a driver paid by the mile, or on a delivery schedule measured in minutes, that overtake is rational.
Payment by mileage is illegal in Germany, as a trucker you need to be paid by the hour and you need to be paid under German minimum wage law as long as you're physically on German roads. Trucker companies from Eastern Europe are infamous for evading that, but as our customs enforcement (who also do the road inspections for rest breaks and minimum wage) ramps up, it's getting better.
The remaining problem are the dispatchers, quite a few of them hand out routes to their drivers that are barely achievable when operating legally (i.e. trucks with working speed governors, drivers taking their rest breaks). Competition is fierce, there used to be talks about passing laws to force dispatchers to not give barely-legal orders but I'm not sure where these went following our government's collapse last year.
> An electric drivetrain achieves around 90%, so you only need roughly 1,600 kWh of battery capacity for equivalent range.
Yup, and most importantly, you mentioned regenerative braking cutting down on brake wear - but it's not just cutting down there, the truck can actually save a fair amount of energy as well, at least outside of highways where the truck is mostly just coasting along.
Trucks, given the right infrastructure, are also viable for running them electrically in the mid-range nowadays as a result.
For 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, that means a half of the stated number, 7.5 tons for the battery pack.
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.
Is this correct — HGVs can go faster on dual carriageways than motorways?
"UK speed limits for heavy vehicles are also more complex than most car drivers realise. Articulated trucks over 7.5 tonnes: 60 mph on dual carriageways, 50 mph on single carriageways, 56 mph (limiter) on motorways"
Sorry, got mixed up there, will amend, the 60 is for +3.5t!
Edit: Nope, despite the vehicles only being able to propel themselves to 90kmph, the speed limit is indeed 60mph (in England and Wales, Scotland is a more sensible 56mph)
Good spot, and gruez is right about the caption too (fixed both, thanks).
The car's L/hr figure was wrong. At 45 mpg (imperial) and 70 mph cruise, a car burns ~7 L/hr, not 3. That makes the flow rate ratio ~4x, which is consistent with 5x per mile and the truck travelling 20% slower.
The ~3 L/hr I originally had is what you'd see as an average over a mixed driving cycle — ~30 mph mean across urban, suburban, and motorway. I was carelessly mixing the cars combined-cycle flow rate with the truck's cruise-only figure in the same row.
The truck doesn't have this problem because a long-haul artic genuinely spends most of its operating hours in that narrow 50-60 mph cruise band. "Average fuel burn rate" and "fuel burn rate at cruise" are nearly the same number. For a car they're very different, transient acceleration, idling in traffic, and low-speed urban driving all drag the average flow rate down well below the motorway figure.
great 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.
I just hadn't read the entire essay yet, so if anything my failing was "commenting etiquette" not "reading comprehension." Mea culpa.
In my defense it seemed to be written as a standalone point, after which the author seemed to move on to another topic. That's why I thought it was safe to comment.
> 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.
> 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, you should expect to travel in convoy with that truck even through manufacturing tolerances mean your limiter is actually set to 90.5.
If the 0.5 km/h is actually valuable to the trucking industry, they can invest in more precise limiters at scale.
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.
> 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.
[1] https://media.gettyimages.com/id/1728143251/vector/no-overta...
Ahh, the power of defaults.
Does it still make sense for that to be "default allow?" Why doesn't the trucking industry lobby for every Truck Overtaking zone, instead of making residents lobby for the opposite?
> This isn’t advisory. It’s a physical limiter in the engine’s ECU. The truck cannot go faster.
I live in Latvia (in the EU) and see a significant part of our ARTICs on the roads go well past 90km/h daily. I presume their fleets do monitor the speed and alert the driver if speeding for a prolonged period of time but they are obviously not physically limited. Maybe the limits do come from the factory but get disabled? I really couldn't say.
A recent journalistic investigation uncovered a problem with the weight limit not being followed on a mass scale too. Specifically by our lumber industry whos drivers are incentivized to break the law. Even if you see a dangerous overloaded truck on the road and call the Police, it is likely no action will be taken because there only a couple of units in the country that are equipped to weigh a freight truck out in the field.
Probably the first thing to consider is the trucks have their speed calibrated periodically to ensure the accuracy of their tachographs (in the UK at least) so a truck doing 90kmph may show as 100kmph+ in a passenger car, I know my Volvo is 7% out, and my Seat is closer to 10% out.
That said, depending on the truck, there's fuses you can pull, ECU remaps and even for the older trucks with the magnetic sensor in the gearbox, the trick is/was to stick a magnet on the sensor (with a bit of string, so you can pull it off remotely if you get pulled over). All of these methods are becoming less feasible, as things like the aggregate wheel speed sensors used for ABS get used, you can't just fool one thing now.
As for the weight limit problem, that's a whole other rabbit hole!
>Most assume the truck driver is being inconsiderate.
You could probably add a whole section of specifically learning to drive a car with trucks on the road to driver education programs and it would do wonders for traffic.
>Anti-idle ordinances exist in several US states and EU regulation is moving in this direction.
Yep, grab a sleeping bag or take your clothes off and use evaporation cooling on yourself. The good news is that car/van camping stuff can apply to trucking as well and that is fairly popular these days.
Another option is simply having places to sleep outside of the truck that are powered by solar/wind and don't cost anything to truckers, but that's only viable when we actually care about reducing emissions over profit.
>Every kilogram you add to the vehicle is a kilogram you can’t carry as freight.
You can save a bunch of weight by not having the sleeper cab if you can readily stop somewhere for a safe place to sleep. There's quite a bit of frontier savings you can do by externalizing costs of transporting stuff to other industries (aforementioned free hotel rooms) and getting tax payers to pay for it, which makes a ton of sense here since trucks are transporting all of the food we eat.
I 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 is so hard to replace, and why 1% fuel savings matters when you're burning 43,000 litres a year.
This is the first in a series, there's already a 2-part deep dive on hydrogen up as well. Tried to keep it accessible without dumbing it down.
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 hybrid model
Trains for longer distances and then electric trucks for last mile
A very well written article! I'd add a few things though.
> Every kilogram you add to the vehicle is a kilogram you can’t carry as freight.
That is only relevant when hauling bulk loads, think ore, soil and the likes, or you're carrying a trailer full of IBC liquid containers. I worked in stage lighting stuff, our trailers were at least 3/4 foam by volume, they didn't even come close to maxing out their weight.
> A battery pack storing equivalent energy would weigh on the order of 16 tonnes at current lithium-ion energy densities.
You don't need to haul a fully equivalent battery. Drivers have to have their mandatory rest breaks of 30+15 minutes here in Germany - that's enough to charge 300-400km of range. Additionally, they can be charged at loading docks, provided the freight base or the customer have chargers set up.
> For a driver paid by the mile, or on a delivery schedule measured in minutes, that overtake is rational.
Payment by mileage is illegal in Germany, as a trucker you need to be paid by the hour and you need to be paid under German minimum wage law as long as you're physically on German roads. Trucker companies from Eastern Europe are infamous for evading that, but as our customs enforcement (who also do the road inspections for rest breaks and minimum wage) ramps up, it's getting better.
The remaining problem are the dispatchers, quite a few of them hand out routes to their drivers that are barely achievable when operating legally (i.e. trucks with working speed governors, drivers taking their rest breaks). Competition is fierce, there used to be talks about passing laws to force dispatchers to not give barely-legal orders but I'm not sure where these went following our government's collapse last year.
> An electric drivetrain achieves around 90%, so you only need roughly 1,600 kWh of battery capacity for equivalent range.
Yup, and most importantly, you mentioned regenerative braking cutting down on brake wear - but it's not just cutting down there, the truck can actually save a fair amount of energy as well, at least outside of highways where the truck is mostly just coasting along.
Trucks, given the right infrastructure, are also viable for running them electrically in the mid-range nowadays as a result.
Really interesting. Much thanks!
Argh the liberal admixture of different units (mpg, kg, L, hr) in the first table really brings home that this is a UK piece.
For 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, that means a half of the stated number, 7.5 tons for the battery pack.
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.
How is fuel consumption per mile 5x but fuel burn per hour 10x?
Is this correct — HGVs can go faster on dual carriageways than motorways?
"UK speed limits for heavy vehicles are also more complex than most car drivers realise. Articulated trucks over 7.5 tonnes: 60 mph on dual carriageways, 50 mph on single carriageways, 56 mph (limiter) on motorways"
Not able to find a source that verifies that
Looks like it's 50 on Dual Carriageways, 60 on motorways[0]
But...speed limiters effectively limit all heavy vehicles to 56mph[1]
Note that speed limiter are mandatory above 3.5 tons, but the legal limits change at 7.5 tons.
[0]https://www.gov.uk/speed-limits [1]https://eptraining.co.uk/news/article/hgv-speed-restrictions...
Sorry, got mixed up there, will amend, the 60 is for +3.5t!
Edit: Nope, despite the vehicles only being able to propel themselves to 90kmph, the speed limit is indeed 60mph (in England and Wales, Scotland is a more sensible 56mph)
https://www.gov.uk/speed-limits
Why is fuel consumption 5x more per mile but 10x more per hour, if the trucks are moving more slowly than cars?
Yeah the numbers in this article are all over the place. "291 seconds" also got rounded off to "over a minute", when it's closer to 5 minutes
Good spot, and gruez is right about the caption too (fixed both, thanks).
The car's L/hr figure was wrong. At 45 mpg (imperial) and 70 mph cruise, a car burns ~7 L/hr, not 3. That makes the flow rate ratio ~4x, which is consistent with 5x per mile and the truck travelling 20% slower.
The ~3 L/hr I originally had is what you'd see as an average over a mixed driving cycle — ~30 mph mean across urban, suburban, and motorway. I was carelessly mixing the cars combined-cycle flow rate with the truck's cruise-only figure in the same row.
The truck doesn't have this problem because a long-haul artic genuinely spends most of its operating hours in that narrow 50-60 mph cruise band. "Average fuel burn rate" and "fuel burn rate at cruise" are nearly the same number. For a car they're very different, transient acceleration, idling in traffic, and low-speed urban driving all drag the average flow rate down well below the motorway figure.
That is simple, that one (very cool) interactive matrix only has that one output description regardless of the input. The effect is clear either way
great 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.
.
They mention this later in the article. It's still about 6 tonnes for the battery to store as much effective energy as the diesel tank.
Thanks. Seems like a confusing way to organize an essay, but okay.
Or your reading comprehension is not good enough. I didn't have any problem finding the paragraph where he author goes into extra detail. Who can say.
I just hadn't read the entire essay yet, so if anything my failing was "commenting etiquette" not "reading comprehension." Mea culpa.
In my defense it seemed to be written as a standalone point, after which the author seemed to move on to another topic. That's why I thought it was safe to comment.
They are addressing that a few pages further down.