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.

You open with

> Every driver in the UK has experienced this. Most assume the truck driver is being inconsiderate.

But then go on to explain how that is exactly true. The truck driver is taking time from *all* drivers on "roughly 4.5 miles of dual carriageway", just so that they can end the day 5 miles ahead.

> The five minutes of inconvenience to you saves them meaningful time and money over the course of a day.

It's five minutes of inconvenience to *everyone* on that 4.5 mile stretch of highway that nets the truck 5 minutes (5 miles ahead at ~60 mph). That's a very selfish and inconsiderate outcome.

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.

Really interesting. Much thanks!

Do you have an RSS feed for your blog?

This is excellent, I'm really looking forward to your piece on fuel additives.