Safe Speed Forums

No, not really...hence le jester

Read my last post again! Perceiving correct and legal use of the road as 'queue jumping' can and does have dangerous and disastrous effects. There have been several accidents at the abovementioned junction that could have been avoided if it weren't for the 'merging early is the RIGHT thing to do' mentality.

'Queue jumping' as you put it, only happens because of the difference in mindset between those who think that merging early and preventing others merging later is is the right thing to do, and those who realise it isn't. Sweep away the 'holier than thou' mindset and the perceived 'queue jumping' disappears, queues get shorter and the traffic keeps moving.

How do I know this? See my example re. the M74 roadworks above.

just making sure. Wouldn't want to start an international incident unnecessarily

Perhaps we should stop calling it a "queue"? I mean, if traffic is heavy in L1 and moving, say 50-60 is that a queue? Are you jumping it if there's a junction a few miles ahead that you want to get off at and you pass the vehicles in L1 by using a clear L2? Or should you just slot into L1 and wait, cos they were there first?

Taken to extremes, no-one would overtake a tractor because it was at the head of a queue and he got on the road first, so why should you overtake him and use the space he's got in front? It's not on, old bean...

I'll swap 'holier than thou' for blatant prejudice. Do you really think that people merge early so that they can prevent others merge later???

Now I see where your mindset comes from; it helps me understand how you think. It doesn't change how I think.

I am amazed! I thought this site was for open discussion of "interesting" driving topics - and so far this thread has been little other than bigoted ranting - on both sides of the argument!

I stil maintain that the main point of all this has been missed - if the traffic is relatively light - there is no problem at all with the zip merge technique - nobody gets held up.

But if the traffic gets heavier - "moving in queues" - then inevitably lane 2 drivers will cause L1 drivers to slow - wherever the merge point is. In general, no problem - so long as everyone uses the same merge point. BUT if 99% of L2 drivers merge at point A, let's say at 200 yards from the cones, then the 1% who merge later will be seen as queue jumpers.

So all we need is some decent signage "Merge in turn here", and the problem will solve itself!

Some people do - deliberately straddling lanes and swerving into perceived queue jumpers. Others, once merged early, tailgate and work hard on maintaining the smallest gap possible to the vehicle in front in order to block later mergers. This sort of active aggressive driving is significantly more selfish, not to mention dangerous if not illegal. The problem is the people who do it can't see that - all they are interested in is their personal crusade to be 'in front', despite the fact that they are further back in a very long queue that is of their and everyone else who thinks like them's making, and those behind suffer even more.

So, the answer is often yes - you cannot carry out the abovementioned activities unless you have already merged.



Yup! And where those signs don't exist, remember how sensible it is to do it, drive to the latest point and merge in turn anyway. Is that so difficult to understand? It seems that although we here are all in agreement that it is the sensible thing to do, while there are still people who need to be told some of us reckon it is better that we all don't and treat those who try with disdain, because they are then committing the worse offence of 'being in front of you'.

Ah-ha! There we have it!

Drive to the latest point? Why? Personally I merge where it is easiest to blend in with the other lane - rather than insisting it must be at the latest point, and those wicked drivers in L1 must let me in because my BMW is bigger and better than their inferior car!

And it is a complete red herring to suggest that a fractionally longer queue will slow the traffic down further - what actually counts is the vehicle flow rate (x cars/hr).

If traffic slows behind the merge point, which is a reasonable assumption, then surely it makes sense to move the merge point as far up as possible.
The further back the merge point moves the further back the traffic's going to slow down - so you end up with a situation of a barely-moving queue of traffic far back from the pinch point, with wasted roadspace ahead of it.

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

BECAUSE THE OVERALL QUEUE ON THE MAIN CARRIAGEWAY WILL THEN BE SHORTER.

See my two examples citing the M8 motorway where the opportunity for later merging has been deliberately ENGINEERED INTO A ROAD as it is seen as a benefit, and why it should become standard practice. OK, so there are times when the longer queue will not in itself cause danger, but there are many more when it will (impinging on junctions), so one set of rules to be used on all occasions avoids confusion, minimises the risk where present, and maintains traffic flow.

Yes, but isf you have two lanes, each carrying x cars/hr, and they merge into one lane then that one lane must carry 2x cars/hr - otherwise everything behind must slow down.
And in order for that lane to carry 2x cars/hr, the spacing between the cars must be halved. This cannot happen if everyone attempts to maintain the same gap - same result, everything behind slows down.

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Only when ideology, prejudice and dogma are set aside does the truth emerge - Kepler

I don't see any ranting. Some vigorous debate but it's all reasonably polite.

Reference your post, L2 later mergers will not cause L1 vehicles to slow if L1 vehicles are leaving adequate gaps. And if traffic is using both lanes up to the obstruction, nobody will be queue jumping. The fact that 99% of drivers merge too early does not justify criticism of the 1% who get it right - provided they are acting with reasonable courtesy.

The "merge in turn here" sign will not work because the optimum merge point varies with speed of approaching traffic. What's needed is: (i) an attitude correction by drivers who cannot bear another vehicle getting ahead of them so seek to protect the space in front of them at all costs; and (ii) a technique correction by drivers who leave inadequate gaps generally (they're related). I suggest that we should see the gap between our vehicle and the vehicle in front as an 'open invitation' for another vehicle to use. If the fact of another vehicle entering it and causes more than a slight, temporary speed adjustment, the gap was too small anyway. If the gap is of an adequate size (relative to speed), vehicles will merge easily and without drama.

Traffic merging early does so faster than the cars jammed up at the last point. If everybody merged early the traffic queue might be longer but it would keep going faster. Merging at the last minute is done at a slower speed and slows things down even more.

Of course having all the traffic in one lane makes that queue longer but if it is moving at constant pace rather than stop start as people attempt to join late then so what.

Difficult to think of a physical analogy but if you were to pour a handful of ball bearings into a funnel then dumping them all in at one go means they would block at the narrow part. Dribbling them in one at a time means they all get through faster.

I have been in lots of queues slowly edging forward at a walking pace and as you get near the cut off point then so someone comes along the other lane and in order for them to get in someone has to actually stop. That stops everybody else.

I think the whole thing would move faster if people merged at speed, as they do on a slip road, then as they got to the narrow part there would be no need to slow down (apart from cameras of course but that is a different story).

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Shooting is good for you and too good for some people.

erm - the traffic has to slow down, because the gaps are smaller. Unless one advocates driving at the same speed with less than half the gap you had previously in front of you? Not SafeSpeed stuff, that!

yes, and it seems it's all been done by you:





got car envy do we?

If the volume of traffic is sufficiently heavy, everybody has to slow anyway to enter the constriction (as Pete317 explained) - although if the road through the constriction is running freely, it's quite likely to run faster through the constriction than the speed at which it is entering. There's no reason why this has to be so - it's another symptom of inefficiency entering the constriction.

Anyway, if L1 traffic does have to slow it's not "because of" the L2 vehicles - simply the fact that the entry to the constriction has to carry twice the volume (unless you're suggesting that all L2 vehicles should wait for all L1 vehicles to clear the obstruction before proceeding).

Both L1 and L2 should slow down the same...

That simply makes no sense. What is "early"? If you're right, then the traffic flow would be improved even more if the two lanes merged even earlier than "early". The optimum merge point will be as close to the constriction as is possible while allowing for a safe merge.

Imagine it is possible to regulate the traffic so each vehicle from L2 merges into L1 at a predetermined distance from the 'lead vehicle' in L1 and the 'trailing vehicle' in L1 and at precisely the same speed. The optimum merge point for maximum flow would be at the point of the constriction. In practice, that is impossible to achieve because of variations in speed and size of gaps. So the merge point needs to move back from the constriction point to provide some safety margin. But that's the only reason. The maximum flow will be achieved if the merge occurs at the constriction.

Your ball bearings and funnel is a false analogy because the two or three lanes leading to a road constriction are completely different to the opening of a funnel.

Observer wrote:

That's a good idea let's have traffic lights and all wait our turn like good little boys and girls.

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Shooting is good for you and too good for some people.

oooh or some kind of see-saw that alternates between the lanes ?