Slow down

[vetran]

I wondered if lorries overtake deliberately to take turns giving each other the aero benefit, but Google suggests it's nothing as interesting. I wonder how much of an effect it is. When we have car/lorry 'trains' who can follow each other incredibly closely, it would presumably be non-negligible.

according to lorry driver friends its to stave off boredom.

[pr1]

I wondered if lorries overtake deliberately to take turns giving each other the aero benefit, but Google suggests it's nothing as interesting. I wonder how much of an effect it is. When we have car/lorry 'trains' who can follow each other incredibly closely, it would presumably be non-negligible.

Gonna be a nightmare for cars who decide they need to come off at the services coming up in half a mile though (travel with young kids, etc) and can't get "through" the train

[vetran]

Stopping distance:

https://www.random-science-tools.com...g-distance.htm

Drag vs speed:

https://mechanixillustrated.technica...-aerodynamics/

And the dear old 55mph blanket speed limit of yore that went along with 145 bhp out of 5 litre V8s back in the 1970s.

so 1 mile=3ft more stopping so 8mph on that last 3 feet seems a bit high.

[d000hg]

Gonna be a nightmare for cars who decide they need to come off at the services coming up in half a mile though (travel with young kids, etc) and can't get "through" the train

Yeah there will be a few things to iron out. I don't think it's a huge issue compared to other things.

[ladymuck]

Yeah there will be a few things to iron out. I don't think it's a huge issue compared to other things.

I suppose the lorry trains could have a dedicated lane that allows access to all exits for other traffic. It worked a treat for the M4 bus lane

[malvolio]

I wondered if lorries overtake deliberately to take turns giving each other the aero benefit, but Google suggests it's nothing as interesting. I wonder how much of an effect it is. When we have car/lorry 'trains' who can follow each other incredibly closely, it would presumably be non-negligible.

Nah, they're running on their speed limiters which obviously will have minor variations in the limit, so while they can get up the hill quicker than the other guy, they can't do it by much. Slowing down to his speed means at least one gear downshift, so it's cheaper to keep going.

The thing is, they are not holding you up by very much - a minute or two over 100 mile journeys - so just wait your turn.

Also, if the motorway is really congested, get in the inside lane with the trucks. It's by far the quickest overall.

[d000hg]

Nah, they're running on their speed limiters which obviously will have minor variations in the limit, so while they can get up the hill quicker than the other guy, they can't do it by much. Slowing down to his speed means at least one gear downshift, so it's cheaper to keep going.

Indeed. Running on a limiter, it's much more work for the driver to reduce speed and follow the truck ahead, unless they have adaptive cruise control which would let them keep their distance as easily.

The thing is, they are not holding you up by very much - a minute or two over 100 mile journeys - so just wait your turn.

One minute for each of the hundreds(?) of cars who are held up, vs probably a few seconds for the lorry itself.
And it's well known that fluctuating speeds on busy roads causes tailbacks and problems - probably accidents too - as well as increased stress and fuel consumption, when a stream of 70mph traffic hits a 60mph obstacle.

Also, if the motorway is really congested, get in the inside lane with the trucks. It's by far the quickest overall.

Yeah agreed. Even if the road isn't too congested, this can be far less stressful. You just pootle along without the mental energy constantly looking for openings and slow-downs. With adaptive cruise control especially it is considerably less draining on a longer journey, as long as you don't get too relaxed and doze off.

[BoredBloke]

I suppose the lorry trains could have a dedicated lane that allows access to all exits for other traffic. It worked a treat for the M4 bus lane

Work out which lorries are going to and from the same cities and you could chain them together. They would then only 1 driver sat in the front lorry. As these lorry trains would cause more wear and tear on the motorway then why not make the surface out of something more durable....like steel. And why not remove the tyres and have the bare wheels run on thing steel tracks....you wouldn't want to cover the whole lane in steel!

On the smart motorways, when things are slowed to 50 it can be a nightmare getting into lane 1 to get off the motorway due to all the trucks being able to match the speed of the rest of the traffic. Lorry trains would make this worse. I'd suggest investing in a completely separate network of steel rails for these lorry trains to run on!

[d000hg]

Work out which lorries are going to and from the same cities and you could chain them together. They would then only 1 driver sat in the front lorry. As these lorry trains would cause more wear and tear on the motorway then why not make the surface out of something more durable....like steel. And why not remove the tyres and have the bare wheels run on thing steel tracks....you wouldn't want to cover the whole lane in steel

But the whole point is lorries aren't all going to the same place. They DO use trains/ships for that sort of thing. Ad-hoc chaining between road-users on the other hand has huge benefits, for cars as well as lorries - self-driving cars are one option but advanced following tech is much simpler. You can have greatly reduced gaps between cars, improve safety, etc.

Also, I have travelled by rail in the US, where freight rail is a huge thing. It causes big problems.

[vetran]

Work out which lorries are going to and from the same cities and you could chain them together. They would then only 1 driver sat in the front lorry. As these lorry trains would cause more wear and tear on the motorway then why not make the surface out of something more durable....like steel. And why not remove the tyres and have the bare wheels run on thing steel tracks....you wouldn't want to cover the whole lane in steel!

On the smart motorways, when things are slowed to 50 it can be a nightmare getting into lane 1 to get off the motorway due to all the trucks being able to match the speed of the rest of the traffic. Lorry trains would make this worse. I'd suggest investing in a completely separate network of steel rails for these lorry trains to run on!

Maybe we could restrict truck drivers to driving at night charging tolls for day driving?

Maybe we could put the freight on something with steel rails that doesn't block up the motorway?
Maybe we could even use water to move them in an eco friendly way like our ancestors did?
Imagine an EV tug on the towpath or locked onto a rail near the bank.