On Monday or thereabouts, Questor declared ...
Post by Questor Post by Whiskers Post by Questor Post by Whiskers Post by Questor
I'm not sure what all the hullabaloo regarding merging is about. The
traffic engineers have clearly indicated the point at which merging is
required: it's where the dotted line between the lanes ends. That is
the merge point.
I'd say it's a bit late by then. Get to that point and someone is going
to have to stop - possibly the entire queue of traffic in both lanes.
That isn't 'optimal'.
If the traffic engineers wanted the merge point to be earlier, they would
have re-stripped the road to end the dotted line earlier. I do not
understand why people reject the obvious location and create imaginary
merge points. Merging is required at the merge point. Merging is
voluntary prior to the merge point.
If both lanes are congested -- i.e., filled with slow-moving traffic --
then it is fairly obvious that a zipper merge at the merge point is best.
On the other tentacle, if the road is otherwise empty, then it is also
obvious that waiting until the merge point to exit the terminating lane
results in no disruption.
In between those extremes, the issue is as previously stated, one of
"finding a hole" and changing lanes with minimal disruption to other
vehicles. If the hole happens to be at the merge point, how is that a
problem? Conversely, merging well in advance of the merge point in no way
precludes a clumsy maneuver that causes traffic to slow down.
Where do these holes into which you an merge, come from? Do other
drivers have nothing to do with it?
The holes are simply the gaps between vehicles. They are either big enough
to allow a driver in the terminating lane to merge smoothly into them without
any action required by drivers already in the lane, or they are not. If they
are not, and that is not a brief, temporary condition, then the roadway is
headed for a slowdown regardless of whether drivers follow your advice or
Post by Whiskers
Of course people /can/ merge clumsily wherever they do it. But it isn't
likely if it's done sensibly when someone offers you the space, whereas
it almost certainly will happen if you have to resort to bullying your
way in at the last moment.
Post by Questor Post by Whiskers Post by Questor
At speed -- very likely in a sparsely populated state such as New Mexico
-- the issue is largely one of courtesy: merging into the one lane
without disrupting other vehicles by "finding a hole" somewhere before
the merge point.
In heavily-congested traffic, optimal roadway utilization dictates both
lanes be filled with vehicles up to the merge point whereupon a zipper
merge should be performed.
Best results are obtained when the drivers in the lane being merged
into, allow the vehicle in front of them to get a bit further away so
that the drivers being required to merge have a space to merge into
without anyone having to change speed significantly or change direction
abruptly. If both sets of drivers manage a 'one for one' arrangement,
everything happens so smoothly that passengers might not even notice.
That might be a wonderful fantasy of drivers acting as if they were lines
of synchronized chorus girls, but it does not align well with reality. It
is the responsibility of the drivers in the terminating lane to safely
merge into the remaining lane. Courtesy dictates the other drivers should
"let them in" if appropriate, but they have no obligation to slow down to
create spaces as you suggest.
So the gaps into which the merging drivers have to merge, appear
magically in the other lane, without drivers in that lane doing anything
to make room? Not on my planet. Courtesy is an essential part of
driving. If you manage to merge smoothly, no matter where you do it,
you do it thanks to someone else's courtesy - even if you don't notice
it. If you get as far as the end of the lane, then you've probably
already ignored several merge opportunities offered to you by courteous
drivers in the other lane.
What do you think happens to the vehicles behind you when you slow down to
create a space for another vehicle to merge in front of you? They have to
slow down too. And if they follow your advice, they will slow down even more
to create spaces in front of them, and so on. The net result: the
continuing lane is congested and slows down, perhaps to a crawl. So now the
terminating lane is empty, the continuing lane is slow, and a driver
approaching the rear of this situation has a choice: slow down immediately,
so as to merge into a crawling lane well in advance of the merge point, or
continue on in the empty terminating lane, and then slow down and merge at
the designated merge point. The correct choice seems obvious to me, but then
I don't like waiting in traffic unnecessarily.
Post by Whiskers Post by Questor Post by Whiskers
Of course, there are always idiots who can't bear to have empty
road-space between them and the car in front, even for a moment, or who
insist that they leave every manoeuvre to the last possible chance or
must always be 'in front' - and come to a sudden stop if no-one lets
them get away with it.
There is nothing to "get away with" -- those drivers simply merged poorly,
albeit possibly intentionally so. The notion that they are "getting away"
with something implies they should have merged at some imaginary merge
point in advance of the actual merge point as indicated by the road
How can you guarantee that a driver reaching the end of the lane he is
in, will find that there is a gap in the traffic in the next lane
allowing him to 'merge' at that point? What happens when there isn't?
There is no guarantee, but the situation is simple. Either the gaps between
vehicles are large enough to permit drivers to merge into them without
appreciable action on the part of other drivers, or they are not. If they
are, then there is likely to be a large enough gap with in a couple hundred
yards of the merge point. If the gaps are not large enough, then there
*will* be some congestion. That congestion starts at the merge point if one
follows my advice. If drivers follow your advice, the congestion starts well
in advance of the merge point, and to the extent that drivers follow your
directives, will extend further and further as drivers abandon an otherwise
empty lane to merge into a lane of slow traffic in advance of the actual
Post by Whiskers
What does anyone lose by merging or allowing others to merge before the
lane peters out? Why do the engineers put up signs well in advance of
that last chance if they don't want people to merge before getting
Engineers put up signs well in advance of merges for the same reasons they do
so for exits: to give drivers a chance to wake up and figure out what the
hell they're going to do.
From my POV, the problem is that you want to use a behavior suitable only for
light traffic when the road is congested, and for failing to recognize that
congestion is not just when there is bumper-to-bumper traffic crawling at
10mph, but occurs even at near highway speeds if the gaps between vehicles
are not large enough to allow for merging.
You're both optimists, but Questor more so. Many times terminating
lane driver at the termination point can only get over by being rude or
depending on the kindness of others. This causes a WHOLE LOT OF SLOWING
at the very-last-moment-merge-point, often to the point of complete
stops. I've seen this on freeways, but the conditions then generally
limit the approach speed to 50 mph or under.
I've also been driving in an almost-empty terminating lane (lane
closure for bridge maintenance in the most memorable case), and made
the mistake of swooping along, only to have someone from the through
lane decide to pull out and seek his fortune up ahead, forcing me to do
emergency braking and start measuring the shoulder.
I've plenty of experience with SoCal merges on freeways. For instance,
the 22W (SR22, officially, in the westbound direction) merges with
I-405N by turning 3 lanes into one (two step-downs).
And as Whiskers noted, those who to the last moment to merge often
encounter hostility from those in the remaining lane.
2 miles later, the on ramp from Seal Beach Blvd happens a couple
hundred feet before the western stub of the 22 peels off 1 lane, and a
2nd lane gets peeled off for I-605N within another quartermile. Lots
of fun the on-rampers who want to go to Carson or LAX. The traffic
that wants to go 22Stub/7th street is light, but the traffic headed to
the 605 is heavy, making for much entertainment for those who want to
be to the left of it.
And the 405 has lots of construction zones, and I-5 has its. The big
ones are in San Clemente and Westwood for the San Diego Fwy (doesn't
get too close to San Diego ... only as far as Irvine) and around Sante
Fe Springs for the Old Route.
One of the one ramps I use, from east Long Beach, runs out with a curb
in the shoulder; since I generally use that one weekend evenings, I've
not had to find out what it feels like when you can't get in in time,
but it figures in my less happy dreams.
Ieri, oggi, domani