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The Physics and Economics of Moving 44 Tonnes at 56mph

mikeayles.com

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Re: The Physics and Economics of Moving 44 Tonnes at 56mph

#41

Post by ReptileMan »

>. That’s roughly 28 to 35 litres per 100 km, or around 30 litres per hour at cruise speed. This is not a misprint. A truck burns in an hour what a small car burns in a week.

Let me paraphrase - a truck weighting 25 times more than a car burns only 4 times as much fuel per 100km at corresponding cruising speeds.

> At 0.25 kWh/kg, that’s still about 6.4 tonnes of battery — roughly 18 times heavier than the 350 kg diesel tank and fuel it replaces, and 6.4 tonnes of payload that disappears from every trip.

And how many tonnes of internal combustion engine, gearboxes and plumbing? It is not an insignificant matter

Re: The Physics and Economics of Moving 44 Tonnes at 56mph

#42

Post by close04 »

hnthrow0287345 wrote: post #21

>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 n…

> Yep, grab a sleeping bag or take your clothes off and use evaporation cooling on yourself.

Talking about driver education, refrigerated trucks never get to turn off the engine until they unload the cargo. So it's not always for comfort.

> if you can readily stop somewhere for a safe place to sleep

That's the missing infrastructure. Drivers pull over to sleep when they hit their daily driving limit and in Europe most of the places to pull over are plain old parking lots maybe with some services like a gas station. Motels are relatively uncommon. I think losing some of the driving day and paying for a motel more than make up for the benefit of a lighter cab.

Re: The Physics and Economics of Moving 44 Tonnes at 56mph

#43

Post by entuno »

close04 wrote: post #29
dmurray wrote: post #8

> 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…

I've also seen roads that have these kind of signs, but they only apply during busy hours.

However, as with any traffic controls they're useless if they're not actually enforced. Which is a shame, because it'd be absolutely trivial to automate that detection with cameras.

Re: The Physics and Economics of Moving 44 Tonnes at 56mph

#44

Post by izacus »

NomadicDaggy wrote: post #11

> 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?…

Tachographs are mandatory and monitored across the EU so I very much doubt that's really happening.

Re: The Physics and Economics of Moving 44 Tonnes at 56mph

#45

Post by ZeroGravitas »

The (bad) justification for overtaking seems a much better justification for the slower truck to fix their calibration and go faster.

Lots of good info but it all feels a bit like it is being used to create a "just so story" to support whatever the current status quo is.

Re: The Physics and Economics of Moving 44 Tonnes at 56mph

#46

Post by matsemann »

dmurray wrote: post #8

> 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…

> Most assume the truck driver is being inconsiderate.

From the article. Then goes on to show exactly how they're inconsiderate with maths. How they're not seeing it is baffling.

Re: The Physics and Economics of Moving 44 Tonnes at 56mph

#47

Post by mikeayles »

kqr wrote: post #38
mikeayles wrote: post #2

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 i…

Do you have an RSS feed for your blog?

I do now: https://www.mikeayles.com/rss.xml

Re: The Physics and Economics of Moving 44 Tonnes at 56mph

#49

Post by citrin_ru »

> Rail is superb for what it does: moving bulk commodities... The problem is last-mile.

Before around 1950x-1970x rail networks were more dense (at least in Europe) - any significant goods source/destination (like a warehouse, a factory e. t. c.) had a railway spur. Lots of rail tracks / spurs were abandoned /removed when it was widely believed that trucks are the future and railways are outdated.

If all these spurs were kept last mile problem would not be as bad for railways. Also electric trucks are well suited to solve this last mile problem.

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