Lorry overtaking ban, M11

I thought the idea was to stop lorries over taking each other slowing the rest of the traffic down.

If only the lorry drivers could use their common sense and only overtake lightly loaded lorries. But two heavily laden lorries in an overtaking situation will snarl the traffic terribly.

Yes, but only on the up hill stretches. In my opinion the is more opportunity for lorries to overtake with a better speed differential on the up hill stretches than on the level or the down hill parts. There are only two lanes on the M11.

That's why this new rule or law whatever it is only applies to certain sections isn't it ?

This also reminds me of the esculator idea on getting people moving 'faster' by not walking up esculators.

Aren't they usually up against the limiter anyway, unless it's a very steep hill?

Nothing to do with loading. All to do with speed limiters

yes.

If you'd ever sat behind 2 "elephant racing" lorries for mile after mile after mile, you'd think it was a good idea, as I do.

I have seen the entire M4/A34->M3/A34 slowed for 27 miles because of a series of lorries playing roadblock.

I also notice that the stretch the other way (towards the M40) *does* have restrictions in place to prevent this behaviour. The landscape geography is no different to the M4-M3 stretch. However David Cameron does live there ????

"Doing the commercial two-step"

Yes I've been a victim of them on the A34, from M4 J13 (Newbury) to Didcot many times. It's better now they've brought in the HGV-overtaking ban on Gore Hill (the steep hill just south of Didcot), but it's still a problem - mainly because so many HGVs use that route from Southampton to Birmingham.

M1 from M18 to Ferrybridge (start of 3-lane motorway rather than 2-lane dual-carriageway) is bad too at times.

That's such a short section (~ 1 mile?) that it doesn't really make any difference.

The main problem comes on level sections, where a lorry's speed is determined by its governor, more or less regardless of the state of loading. So when one lorry overtakes another, the closing speed is determined by slight differences in their governor settings - and the manoeuvre can literally go on for miles.

That may be true on the level. But going up hill, few lorries can reach the speed limiter speed and their speed is determined by power to weight ratio.

No. It doesn't need much of a gradient to slow them down. A heavy lorry's drag to weight ratio and rolling resistance to weight ratio are quite low. But add to that a component of the weight as a result of the slope, and the required tractive effort increases dramatically.

Roger Mills formulated on Friday :

Exactly, which is why the best place for over takes to take place, is on the hill climbs rather than ban them there.

I though it took longer to climb hills irrespective of the type of vehicle, so why encourage it ?

You might think that but the results of the experiments carried out on the M11 under an experimental traffic order for 18 months starting 26March

Alan

I have a vague memory that there was an earlier experiment on the M42 past the NEC/M6 junction.

Sure Belgium has been doing this for years - seemed that way last time I was there.

And yes, it was incredibly civilised - at least until the R0 ring outside of Brussels which was slightly mad (but nothing compared to La Peripherique around Paris which is mental).