Two Lanes Merging, Only One Gets Its Own Lane

[coatimundi]

I searched for an existing topic on this but was unable to find any, though I also don't know if I'm using the correct terminology.

The scenario is such:
A ramp with two lanes (or more) merges into a multi-laned roadway. The right lane(s) on the merging ramp gets its own lane while the left does not and must immediately merge.

Examples:
The worst I've seen is in San Francisco, at 101/80, which is so bad because you cannot see traffic coming in on your left when on the 101 until you're almost on top of them. But this interchange is almost always backed up, so it doesn't seem to matter that much.
https://www.google.com/maps/@37.766537,-122.4053868,118m/data=!3m1!1e3

Another example in California near me, at 1/156, where there's a large amount of space given to allow people to merge.
https://www.google.com/maps/@36.7509069,-121.7678207,99m/data=!3m1!1e3

Another at 101/680 in San Jose, where you can see that they actually striped a brief merging lane. This one has three lanes merging:
https://www.google.com/maps/place/San+Jose,+CA/@37.3434158,-121.8460836,97m/data=!3m1!1e3!4m5!3m4!1s0x808fcae48af93ff5:0xb99d8c0aca9f717b!8m2!3d37.3382082!4d-121.8863286

There are a couple of other examples I can think of in California, but Houston had one for years, at I-45 North/I-610, from NB 45 to EB 610, but they restriped it so that the second lane ends on the ramp.
https://www.google.com/maps/@29.8133052,-95.3729883,85m/data=!3m1!1e3

In many cases, it seems like most drivers who know about this avoid the immediate-merge lane on the ramp.

I'd be curious to hear of other examples and how well they work as far as traffic flow.

[jeffandnicole]

Like this? https://goo.gl/maps/WnQ1pAAuRdK2  The AC Expressway (left) meets with Rt. 42 (right).  The ACX left lane and Rt. 42 right lane continue thru.  The ACX right lane and the Rt. 42 left lane merge into one lane.

While it's not exactly the ramp that you're referring to, it's basically the same thing.  In this case, the combined lane gets a good amount of use, and people are generally aware of it enough to zipper it pretty good maintaining a constant speed.

[coatimundi]

Yes, that's what I was referring to. It looks like some space is given there to mitigate the surprise of seeing someone closing in on you in your lane, and you can see the merge coming for some time on both sides. I would say this is executed quite well.

[jeffandnicole]

I would personally rather have the left lane end a bit down the road like a normal merge.

The NJ Turnpike, at the dual-dual merge point south of Interchange 6, has a similar situation where the inner right lane and the outer left lane zipper into each other.  That one is much more extended (and well signed) compared to the ACX/42 example above.

[Ian]

There's a similar situation at the north end of I-295 at I-95 (Maine Turnpike) in Gardiner, ME. The left lane of the ramp from 295 north merges immediately with the right lane from 95 north, with the other lane from the ramp ending several hundred feet ahead of this point. Luckily you can see well ahead of the merge point if a car is coming up on you, so I don't mind this one too much.

Another one that I do mind more, is where the northbound ramp from I-495 merges onto I-95 north at its north end near Salisbury. I drive this one every time I go back up to Maine, and I'll always move to the right lane on the 495 ramp to prevent the hassle of this "merge or die" situation.

[myosh_tino]

I searched for an existing topic on this but was unable to find any, though I also don't know if I'm using the correct terminology.

The scenario is such:
A ramp with two lanes (or more) merges into a multi-laned roadway. The right lane(s) on the merging ramp gets its own lane while the left does not and must immediately merge.

I deal with this on a daily basis as there are two such instances of this at the 280/85 interchange in Cupertino (north 280 on-ramp to north 85 and 85 on-ramp to north 280.  In both cases, traffic in the left lane on the ramp must merge with mainline traffic.  The 85 on-ramp to north 280 is particularly bad because the right lane becomes an exit-only lane for the Foothill Expwy exit which is less than a 1/4 mile away.

[vdeane]

This happens at the I-81/I-88 interchange.
https://www.google.com/maps/@42.1367953,-75.9029023,304m/data=!3m1!1e3

[johndoe]

If you are looking to learn more, I've heard them referred to as "inside" or "tapered inside" merges.  Illinois is another state that seems to regularly use them.  I can't imagine a scenario where it would be more desirable than a parallel merge that drops on the outside.

[hbelkins]

Several of these in the Charleston, WV area. They're signed as a "Left Lane Merge" on the ramp that loses a lane.

In one case, where westbound US 60 merges onto I-64/I-77, the right lane becomes an exit-only lane for US 60's immediate departure from the freeway.

[Ned Weasel]

If you are looking to learn more, I've heard them referred to as "inside" or "tapered inside" merges.  Illinois is another state that seems to regularly use them.  I can't imagine a scenario where it would be more desirable than a parallel merge that drops on the outside.

Not only are these all over Illinois, but Illinois is the only place where I recall seeing two lanes taper at the same merge.

Examples:

https://goo.gl/maps/uVowQecFhbR2
At least the merge is smooth and gradual.  I've driven through this so many times that I'm used to it, and I've never seen a problem here.

https://goo.gl/maps/ph3we4qdLdv
I wouldn't call this a bad merge, either.  My problem with this interchange is unrelated to the tapered merge.

[Brandon]

If you are looking to learn more, I've heard them referred to as "inside" or "tapered inside" merges.  Illinois is another state that seems to regularly use them.  I can't imagine a scenario where it would be more desirable than a parallel merge that drops on the outside.

Not only are these all over Illinois, but Illinois is the only place where I recall seeing two lanes taper at the same merge.

Examples:

https://goo.gl/maps/uVowQecFhbR2
At least the merge is smooth and gradual.  I've driven through this so many times that I'm used to it, and I've never seen a problem here.

https://goo.gl/maps/ph3we4qdLdv
I wouldn't call this a bad merge, either.  My problem with this interchange is unrelated to the tapered merge.

Or like this one:

https://goo.gl/maps/qp6S93thYow

[1995hoo]

Been a few years since I've used this route, but the ramp from the Verrazano Bridge to the Belt Parkway (heading towards Coney Island) used to be configured that way and likely still is.

[jeffandnicole]

If you are looking to learn more, I've heard them referred to as "inside" or "tapered inside" merges.  Illinois is another state that seems to regularly use them.  I can't imagine a scenario where it would be more desirable than a parallel merge that drops on the outside.

Not only are these all over Illinois, but Illinois is the only place where I recall seeing two lanes taper at the same merge.

Examples:

https://goo.gl/maps/uVowQecFhbR2
At least the merge is smooth and gradual.  I've driven through this so many times that I'm used to it, and I've never seen a problem here.

https://goo.gl/maps/ph3we4qdLdv
I wouldn't call this a bad merge, either.  My problem with this interchange is unrelated to the tapered merge.

Or like this one:

https://goo.gl/maps/qp6S93thYow

That's just a standard gradual lane drop from the right.  Strident's examples show the two center lanes merging.

[wanderer2575]

My vote for worst example is in downtown Detroit where northbound I-75 merges to itself transitioning from the Fisher Freeway to the Chrysler Freeway.  The merge point is not at all gradual and visibility is limited due to the Jersey barrier and height difference (spin the Street View image around 180 degrees and you'll see what I mean).  This is a terrible setup.  The right lane of the northbound Chrysler should be painted out to eliminate the lane merge.

https://goo.gl/maps/stPyh72mvNL2

[epzik8]

I think the ramp from Maryland Route 24 south to U.S. Route 1 south (the "Bel Air Bypass") near Bel Air, Maryland is one. I know it starts as a two-lane ramp because living in that area I've obviously been on that ramp many times in my life.

[jeffandnicole]

I think the ramp from Maryland Route 24 south to U.S. Route 1 south (the "Bel Air Bypass") near Bel Air, Maryland is one. I know it starts as a two-lane ramp because living in that area I've obviously been on that ramp many times in my life.

While it starts as a 2 lane ramp, again, just a standard land drop midway down the ramp.

[cl94]

Ohio loves these, especially in the Cleveland area. There's one at either end of the I-271/I-480 concurrency, 3 at the I-90/I-271 interchange and many more in that area. In Columbus, there's one at I-270/I-670.

[jemacedo9]

US 15 South merging into I-180 East in Williamsport.  The left lane from the ramp merges (and there is a Yield sign with a LEFT LANE sign underneath), and the right lane of that ramp becomes an Exit Only lane for I-180 Exit 28.  On the US 15 ramp itself, the right lane is signed as the Exit 28 Exit Only ramp even though you're not technically on I-180 yet.

[paulthemapguy]

There's a sign that's starting to become more common, that signifies this exact scenario.  One example: https://www.google.com/maps/@41.5775979,-87.5699497,3a,52.1y,117.96h,89.46t/data=!3m6!1e1!3m4!1sKwo-oxogWzsqvCFxDaB3IA!2e0!7i13312!8i6656

I saw a couple more in my drive to the South.

[Brandon]

That's just a standard gradual lane drop from the right.  Strident's examples show the two center lanes merging.

And I was mentioning a different, yet similar situation.  I sure as hell didn't expect the analroadgeek.

[Jet380]

We have one of these near Murdoch University in Perth, Australia. They've added a 'tiger tail' between the merging and non-merging lane to make the arrangement more clear and to provide a bit of a safety buffer; the left lane shifts to meet the other lanes further down the road.



goo.gl/E64dGJcontent_copyCopy short URL

[1995hoo]

Been a few years since I've used this route, but the ramp from the Verrazano Bridge to the Belt Parkway (heading towards Coney Island) used to be configured that way and likely still is.

According to Street View, the location noted above is still like this with the same yellow warning sign:

https://goo.gl/maps/T3YjpnmNpLt

[ne11931]

Route 3 interchange with 495 North and South in Chelmsford Ma.
Chelmsford, Massachusetts

https://goo.gl/maps/vZGqbompLmM2
There is no signage or striping to guide drivers so many times you end up with five lanes of traffic in the no man's land this creates. Hopefully an ongoing paving project will rectify this but I haven't been through there lately.

[Brandon]

This might be a useful warning sign for this: https://goo.gl/maps/D9ABjmx3VtM2

[Revive 755]

There's a sign that's starting to become more common, that signifies this exact scenario.  One example: https://www.google.com/maps/@41.5775979,-87.5699497,3a,52.1y,117.96h,89.46t/data=!3m6!1e1!3m4!1sKwo-oxogWzsqvCFxDaB3IA!2e0!7i13312!8i6656

Iowa has their own version of that sign at the western I-35/I-80/I-235 interchange.  They use this merge design a couple times in Des Moines.

I also recall one or two of these merge designs in Kentucky, and one near the Borman in northern Indiana.



None of the merge signs shown so far are MUTCD compliant, although I recall reading somewhere Ohio had permission from FHWA to experiment with one.  Seems Ohio was having an accident problem at at least one of these inside lane/forced merges.