For instance, let's say 3 lanes, northbound, goes to 2 lanes. Instead of dropping either outermost lane, is there anyplace in the country where the center lane must merge into either or both other lanes ?
I realize this sounds like a guaranteed way to have continuous accidents, but that isn't always a consideration in laying out a highway.
:pan:
Quote from: Jardine on October 19, 2015, 07:22:55 PM
For instance, let's say 3 lanes, northbound, goes to 2 lanes. Instead of dropping either outermost lane, is there anyplace in the country where the center lane must merge into either or both other lanes ?
I realize this sounds like a guaranteed way to have continuous accidents, but that isn't always a consideration in laying out a highway.
:pan:
It's common for lanes that have an express-local setup. For a while in 2010 or so, I-81 through Harrisburg temporarily went express-local with its lanes due to construction. There were 3 lanes. The middle lane ended at the beginning of the setup, meaning the left lane was express, and the right lane was local.
The ramp from the Verrazano Bridge to the Belt Parkway had two lanes converge in the center. I do not know if it still exists but when I was there in 2001, an overhead sign warned motorists of the two lanes converging.
https://www.google.com/maps/place/Bay+Ridge,+Brooklyn,+NY/@40.605348,-74.030769,3a,66.8y,292.4h,82.82t/data=!3m4!1e1!3m2!1s9He29U-_BXosemoFLY_GJA!2e0!4m2!3m1!1s0x89c2455f3f1cab0d:0xa5a45198ea4d73d6
GSV shows it still but the overhead is gone. Some may argue that the left lane ramp from the bridge just merges into the right lane of the Belt Parkway, however from what I see both roads are equal with traffic and you could consider it to be two 2 lane roads widening into one 3 lane roadway.
Looks like they tried restriping the lines so that the bridge merge narrows to the right lane exclusively. Now, though its back and may be why the sign is gone that was there in 01.
This happens quite often in the Cleveland area. For example, both ends (https://www.google.com/maps/@41.3542823,-81.5116796,242m/data=!3m1!1e3) of the I-271/I-480 concurrency (https://www.google.com/maps/@41.3542823,-81.5116796,242m/data=!3m1!1e3), on I-480N at the I-271/US 422 interchange (https://www.google.com/maps/@41.4276935,-81.5136122,291m/data=!3m1!1e3), I-281 NB (https://www.google.com/maps/@41.4374891,-81.4975146,201m/data=!3m1!1e3) at the same interchange, the I-90/I-271 interchange on I-271 (https://www.google.com/maps/@41.5860745,-81.4488142,283m/data=!3m1!1e3), WB I-90 (https://www.google.com/maps/@41.5908362,-81.4540076,286m/data=!3m1!1e3), and EB I-90 (https://www.google.com/maps/@41.5965469,-81.4446304,292m/data=!3m1!1e3), I-480 at I-77 (https://www.google.com/maps/@41.4078647,-81.635934,243m/data=!3m1!1e3), and I-90 at I-490 (https://www.google.com/maps/@41.4742033,-81.7004449,250m/data=!3m1!1e3).
Go down to Akron and you have I-76/77 at SR 59 (https://www.google.com/maps/@41.062305,-81.5442842,247m/data=!3m1!1e3). In Columbus, there's I-670/US 62 at I-270 (https://www.google.com/maps/@40.0117168,-82.9077608,176m/data=!3m1!1e3) and I-270 SB at the same interchange (https://www.google.com/maps/@40.0087767,-82.8959984,157m/data=!3m1!1e3). I'm not going to link them, but it's present a couple exits further south on I-270 and another on I-70 at its western interchange with I-270.
https://www.google.com/maps/place/Bay+Ridge,+Brooklyn,+NY/@40.606666,-74.032683,3a,66.8y,165.63h,93.69t/data=!3m4!1e1!3m2!1sil_GmGdjclohjYzq11hwNQ!2e0!4m2!3m1!1s0x89c2455f3f1cab0d:0xa5a45198ea4d73d6
I did not pan or zoom back far enough, but the sign I saw in 2001 is still there and it depicts both right lane of the Belt Parkway and the left bridge ramp as being equal.
So this merge does count as a lane being dropped from within the borders. Both the left lane Belt and the right lane ramp stay consistent completely.
Quote from: Jardine on October 19, 2015, 07:22:55 PM
For instance, let's say 3 lanes, northbound, goes to 2 lanes. Instead of dropping either outermost lane, is there anyplace in the country where the center lane must merge into either or both other lanes ?
I realize this sounds like a guaranteed way to have continuous accidents, but that isn't always a consideration in laying out a highway.
:pan:
Parts of US 62 in Arkansas have the Left Lane ending.
Missouri's "Shared
Three Four Lane" have the center lane merging
Cases where two roadways converge and the outer lanes continue while the inner lanes merge are common. I assumed the OP was asking about instances where a lane ends on a single roadway, without any convergence with another roadway, but the lane that ends is not an outer lane.
The case of three lanes being reduced to two is trivial and not an example of the hypothetical phenomenon in question. Suppose three lanes narrow to two and the far-left lane continues. Then the right two lanes merge with each other, which is logically equivalent to ending the far-right lane. Now suppose three lanes narrow to two and the far-right lane continues. Then the left two lanes merge with each other, which is logically equivalent to ending the far-left lane.
This only becomes interesting when you have four or more lanes within a single roadway being reduced to a lesser number of lanes. For example, the far-left lane and the far-right lane could both continue. Then the center two lanes would merge with each other. I can't think of any case where this would be a good way to end a lane within a single roadway. However, this is a common way to handle a merge when two separate roadways converge.
One of the closest true center lane merges would be where the NJ Turnpike merges the center lanes after the dual-dual roadway ends, after a short passing zone area.
The AC Expressway & NJ 42 have a center lane merge area as well. The unusual thing with this is that there's no signage whatsoever referring to this merge area.
Better than the original end of the Truck and Bus Lanes at Exit 9 where all three lanes dropped completely before the extension to 8A took place. At least the truck lanes afterwards had continuous lanes as I am sure they do now.
However, I think that the NJTA should have done at Exit 6 what they did at the Eastern and Western Spur split just north of 14. Have the three lanes split into 2 for the 6 ramp and 2 through on both carriageways then the the 2 through lanes merge into the 3 continuing lanes, as well as the 2 ramp lanes merge into the 3 Penn Extension lanes.
You figure that set up is working at the transition of the dual carriageways from the Inner and outer to the two spurs, that the engineers would have copied that design instead of making the Exit 6 like any other interchange along the dual configuration.
Southbound San Tomas Expressway in Santa Clara... https://goo.gl/maps/r29KxSh1ihL2
In this case, there are 4 lanes and the two middle lanes merge into a single lane. The reason why is because the far right lane is an HOV lane (typical for Santa Clara county's expressways).
Quote from: roadman65 on October 20, 2015, 11:55:17 AM
Better than the original end of the Truck and Bus Lanes at Exit 9 where all three lanes dropped completely before the extension to 8A took place. At least the truck lanes afterwards had continuous lanes as I am sure they do now.
However, I think that the NJTA should have done at Exit 6 what they did at the Eastern and Western Spur split just north of 14. Have the three lanes split into 2 for the 6 ramp and 2 through on both carriageways then the the 2 through lanes merge into the 3 continuing lanes, as well as the 2 ramp lanes merge into the 3 Penn Extension lanes.
You figure that set up is working at the transition of the dual carriageways from the Inner and outer to the two spurs, that the engineers would have copied that design instead of making the Exit 6 like any other interchange along the dual configuration.
I remember attending a meeting before the project first started. They said numerous studies showed that what they did at Exit 6, both for the merge and diverge, was the optimal way to go.
Quote from: myosh_tino on October 20, 2015, 12:14:12 PM
Southbound San Tomas Expressway in Santa Clara... https://goo.gl/maps/r29KxSh1ihL2
In this case, there are 4 lanes and the two middle lanes merge into a single lane. The reason why is because the far right lane is an HOV lane (typical for Santa Clara county's expressways).
Well, son of a gun, it does exist! I have to wonder, though, is this really the best way to end a lane there? I can think of three alternatives: (1) end the left lane and then shift the remaining three lanes to the left; (2) exchange the width of the right shoulder for a hard barrier between the HOV lane and the left three lanes, and run the barrier from a point before the lane termination to a point after the lane has fully terminated; or (3) drop the far-left lane as a left-turn-only lane at the preceding intersection (this is probably the least desirable option in terms of maximizing traffic capacity within the available space). But maybe the present configuration works just fine and drivers handle it in a safe and efficient manner. Notice the odd signs informing motorists of the merge, though!
Quote from: jeffandnicole on October 20, 2015, 12:18:34 PM
Quote from: roadman65 on October 20, 2015, 11:55:17 AM
Better than the original end of the Truck and Bus Lanes at Exit 9 where all three lanes dropped completely before the extension to 8A took place. At least the truck lanes afterwards had continuous lanes as I am sure they do now.
However, I think that the NJTA should have done at Exit 6 what they did at the Eastern and Western Spur split just north of 14. Have the three lanes split into 2 for the 6 ramp and 2 through on both carriageways then the the 2 through lanes merge into the 3 continuing lanes, as well as the 2 ramp lanes merge into the 3 Penn Extension lanes.
You figure that set up is working at the transition of the dual carriageways from the Inner and outer to the two spurs, that the engineers would have copied that design instead of making the Exit 6 like any other interchange along the dual configuration.
I remember attending a meeting before the project first started. They said numerous studies showed that what they did at Exit 6, both for the merge and diverge, was the optimal way to go.
You know FDOT here in Orlando did something similar like the truck lanes end before 1991 when it narrowed just south of NJ 18. When John Young Parkway was extended into FL 434, all the lanes of S Bound FL 423 now require you to merge into one lane then the lane drops, and then another lane drops. To stay on FL 423 from Lee Road to JYP you must merge over into the lanes of the new JYP extension that keeps two but one of its three S Bound lanes. No more continuous lanes along FL 423 at John Young and Lee Road.
Where the Kennedy and Edens Expressways merge together in Chicago. 6 lanes merge to 4, and the center lanes merge. Here's the sign.
https://www.google.com/maps/@41.9611312,-87.7439025,3a,75y,145.37h,76.99t/data=!3m6!1e1!3m4!1slFA80JNL9hN9qRWDYM4jxw!2e0!7i13312!8i6656?hl=en
Traffic backs up frequently at this merger.
Quote from: stridentweasel on October 20, 2015, 06:50:26 PM
Quote from: myosh_tino on October 20, 2015, 12:14:12 PM
Southbound San Tomas Expressway in Santa Clara... https://goo.gl/maps/r29KxSh1ihL2
In this case, there are 4 lanes and the two middle lanes merge into a single lane. The reason why is because the far right lane is an HOV lane (typical for Santa Clara county's expressways).
Well, son of a gun, it does exist! I have to wonder, though, is this really the best way to end a lane there? I can think of three alternatives: (1) end the left lane and then shift the remaining three lanes to the left; (2) exchange the width of the right shoulder for a hard barrier between the HOV lane and the left three lanes, and run the barrier from a point before the lane termination to a point after the lane has fully terminated; or (3) drop the far-left lane as a left-turn-only lane at the preceding intersection (this is probably the least desirable option in terms of maximizing traffic capacity within the available space). But maybe the present configuration works just fine and drivers handle it in a safe and efficient manner. Notice the odd signs informing motorists of the merge, though!
I probably would have opted for (1) to avoid this unusual situation. (2) might make some sense but having a hard barrier does present some safety issues and would require the placement of sand barrels at the start of the barrier to prevent cars from hitting it head-on. (3) wouldn't work given the amount of traffic San Tomas handles on a daily basis at that intersection.
I seem to recall that the county wants to add another lane to San Tomas south of El Camino but funding is an issue.
End of NY 85 westbound freeway section at the bridge over the thruway. Center lane disappears. Can be messy at times.
I believe the "right" lane there is the acceleration lane from Krumkill Rd. The other two are supposed to merge into each other.
Quote from: Rothman on October 21, 2015, 01:09:27 PM
End of NY 85 westbound freeway section at the bridge over the thruway. Center lane disappears. Can be messy at times.
Quote from: vdeane on October 21, 2015, 01:18:14 PM
I believe the "right" lane there is the acceleration lane from Krumkill Rd. The other two are supposed to merge into each other.
It's more that the left and right lanes both end, at least that's how it was striped the last time I was through there. It's only messy because it drops 2 lanes at once.
Quote from: cl94 on October 21, 2015, 01:25:29 PM
Quote from: Rothman on October 21, 2015, 01:09:27 PM
End of NY 85 westbound freeway section at the bridge over the thruway. Center lane disappears. Can be messy at times.
Quote from: vdeane on October 21, 2015, 01:18:14 PM
I believe the "right" lane there is the acceleration lane from Krumkill Rd. The other two are supposed to merge into each other.
It's more that the left and right lanes both end, at least that's how it was striped the last time I was through there. It's only messy because it drops 2 lanes at once.
*nods*
New Hampshire has this interesting configuration, pictured is where I-93 NB meets the Everett Tpke just north of Manchester:
https://www.google.com/maps/@43.056154,-71.4711448,3a,75y,16.4h,52.7t/data=!3m6!1e1!3m4!1sP7Gu1erRejMSxPku3wmx1A!2e0!7i13312!8i6656
Three lanes of I-93 meet 2 lanes of the Everett. However, the right lane of the Everett and the left lane of I-93 merge into each other without any lane lines whatsoever. So the green car and the grey truck are actually in the same lane.
On I-55 southbound at the 55/72/6th street interchange in Springfield, IL, the right lane of 55 and the left lane of the 6th street on ramp merge into one lane.
https://www.google.com/maps/@39.7357225,-89.6442704,74m/data=!3m1!1e3
Are we talking about center merges here? There's one at the north (east) end of I-196 where it merges into I-96 on the east side of Grand Rapids.
But I thought this thread was intended to be about just losing a lane, not at a merge.
Quote from: GaryV on October 21, 2015, 07:42:17 PM
But I thought this thread was intended to be about just losing a lane, not at a merge.
Ditto.
Sorry.. my mistake.
Quote from: vdeane on October 21, 2015, 07:44:22 PM
Quote from: GaryV on October 21, 2015, 07:42:17 PM
But I thought this thread was intended to be about just losing a lane, not at a merge.
Ditto.
In many ways, a merge is worse than a lane just ending because neither lane has clear priority. While the Green Book includes standards for such a setup, it is explicitly stated that such a situation is less than ideal and should be avoided.
Quote from: cl94 on October 21, 2015, 07:57:01 PM
Quote from: vdeane on October 21, 2015, 07:44:22 PM
Quote from: GaryV on October 21, 2015, 07:42:17 PM
But I thought this thread was intended to be about just losing a lane, not at a merge.
Ditto.
In many ways, a merge is worse than a lane just ending because neither lane has clear priority. While the Green Book includes standards for such a setup, it is explicitly stated that such a situation is less than ideal and should be avoided.
Yes but if an interior lane ends by merging into another interior lane, or (almost equivalently) two interior lanes merge into one – the situation this thread is looking for – it's just about as hazardous as the common "inside lanes merge" situation where two distinct traveled ways converge.
Found another one similar to the San Tomas Expressway one I posted earlier.
It's located on northbound Wolfe Road in Cupertino approaching the I-280 interchange. In this case, the far right lane is an exit only lane to southbound I-280 and the next lane to the right ends and has to merge with the lane to its left because the Wolfe Road overpass is only 4 lanes wide (2 in each direction).
https://goo.gl/maps/iu2K7jzbpM82
It's kind of hard to see the lane-drop because the pavement markings have worn off in the street view image.
Hey, no problem with all the variations noted above. It turned out to be a very interesting topic, and the diversity of the replies was fun.
Some of the examples would scare the poo out of me if I happened upon them unawares at rush hour.
Eastbound Interstate 80 in Emeryville, California has this type of situation. The left two lanes are HOV lanes and the right lane is dropped.
https://goo.gl/maps/wfeg3basWaT2 (https://goo.gl/maps/wfeg3basWaT2)
Quote from: jeffe on November 07, 2015, 12:39:36 AM
Eastbound Interstate 80 in Emeryville, California has this type of situation. The left two lanes are HOV lanes and the right lane is dropped.
https://goo.gl/maps/wfeg3basWaT2 (https://goo.gl/maps/wfeg3basWaT2)
The configuration would be safer if there was a passing restriction between main lanes and HOV lanes in the area of the lane drop. I know that generally Bay area HOV lanes allow people to change lanes at any time (unlike So Cal) but there should be an exception for at least 1/4 mile in the area of this interchange so that those from the right HOV lane can merge to the left without worrying about somebody from the lane on their right merging in as well. IT can be signified with 4 yellow lines, the same way SoCal signifies no passing zones between HOV and general purpose lanes.
Quote from: myosh_tino on October 23, 2015, 02:26:11 AM
Found another one similar to the San Tomas Expressway one I posted earlier.
It's located on northbound Wolfe Road in Cupertino approaching the I-280 interchange. In this case, the far right lane is an exit only lane to southbound I-280 and the next lane to the right ends and has to merge with the lane to its left because the Wolfe Road overpass is only 4 lanes wide (2 in each direction).
https://goo.gl/maps/iu2K7jzbpM82
It's kind of hard to see the lane-drop because the pavement markings have worn off in the street view image.
This makes no sense at all. If I interpret this correctly, Wolfe Rd has 3 lanes of traffic northbound approaching Vallco Pkwy. It then widens to 4, but the 3rd lane merges into the 2nd lane, so that the 4th lane can lead directly to I-280. At the I-280 ramp, the left 2 lanes continue on Wolfe Rd and the right lane exits onto the interstate.
Why even widen to 4 lanes at all? Simply force the third lane onto the I-280 ramp. There is no need for this complicated setup.
Quote from: jeffandnicole on October 20, 2015, 12:18:34 PM
Quote from: roadman65 on October 20, 2015, 11:55:17 AM
Better than the original end of the Truck and Bus Lanes at Exit 9 where all three lanes dropped completely before the extension to 8A took place. At least the truck lanes afterwards had continuous lanes as I am sure they do now.
However, I think that the NJTA should have done at Exit 6 what they did at the Eastern and Western Spur split just north of 14. Have the three lanes split into 2 for the 6 ramp and 2 through on both carriageways then the the 2 through lanes merge into the 3 continuing lanes, as well as the 2 ramp lanes merge into the 3 Penn Extension lanes.
You figure that set up is working at the transition of the dual carriageways from the Inner and outer to the two spurs, that the engineers would have copied that design instead of making the Exit 6 like any other interchange along the dual configuration.
I remember attending a meeting before the project first started. They said numerous studies showed that what they did at Exit 6, both for the merge and diverge, was the optimal way to go.
As I have not driven by exit 6 since the extension of the dual-dual setup from exit 8A, can someone please tell me in detail how the lanes are now set up? There is no updated GSV as far as I can tell.
One more comment: When two highways merge so that the left lane of one highway and the right lane of the other are forced into one, it is known as an inside lane merge.
Quote from: mrsman on November 08, 2015, 08:44:59 AM
Quote from: jeffandnicole on October 20, 2015, 12:18:34 PM
Quote from: roadman65 on October 20, 2015, 11:55:17 AM
Better than the original end of the Truck and Bus Lanes at Exit 9 where all three lanes dropped completely before the extension to 8A took place. At least the truck lanes afterwards had continuous lanes as I am sure they do now.
However, I think that the NJTA should have done at Exit 6 what they did at the Eastern and Western Spur split just north of 14. Have the three lanes split into 2 for the 6 ramp and 2 through on both carriageways then the the 2 through lanes merge into the 3 continuing lanes, as well as the 2 ramp lanes merge into the 3 Penn Extension lanes.
You figure that set up is working at the transition of the dual carriageways from the Inner and outer to the two spurs, that the engineers would have copied that design instead of making the Exit 6 like any other interchange along the dual configuration.
I remember attending a meeting before the project first started. They said numerous studies showed that what they did at Exit 6, both for the merge and diverge, was the optimal way to go.
As I have not driven by exit 6 since the extension of the dual-dual setup from exit 8A, can someone please tell me in detail how the lanes are now set up? There is no updated GSV as far as I can tell.
As the inner/outer roadways merge, forming 6 lanes. We'll number them from left to right 1,2,3,4,5,6, with the car lanes being 1,2,3 & the truck lanes being 4,5,6.
Lane 1 ends, merging right into lane 2.
Lanes 3 & 4 merge.
Lane 6 ends, merging left into lane 5.
First, the left lane ends, merging into the
Quote from: myosh_tino on October 21, 2015, 02:43:51 AM
Quote from: stridentweasel on October 20, 2015, 06:50:26 PM
Quote from: myosh_tino on October 20, 2015, 12:14:12 PM
Southbound San Tomas Expressway in Santa Clara... https://goo.gl/maps/r29KxSh1ihL2
In this case, there are 4 lanes and the two middle lanes merge into a single lane. The reason why is because the far right lane is an HOV lane (typical for Santa Clara county's expressways).
Well, son of a gun, it does exist! I have to wonder, though, is this really the best way to end a lane there? I can think of three alternatives: (1) end the left lane and then shift the remaining three lanes to the left; (2) exchange the width of the right shoulder for a hard barrier between the HOV lane and the left three lanes, and run the barrier from a point before the lane termination to a point after the lane has fully terminated; or (3) drop the far-left lane as a left-turn-only lane at the preceding intersection (this is probably the least desirable option in terms of maximizing traffic capacity within the available space). But maybe the present configuration works just fine and drivers handle it in a safe and efficient manner. Notice the odd signs informing motorists of the merge, though!
I probably would have opted for (1) to avoid this unusual situation. (2) might make some sense but having a hard barrier does present some safety issues and would require the placement of sand barrels at the start of the barrier to prevent cars from hitting it head-on. (3) wouldn't work given the amount of traffic San Tomas handles on a daily basis at that intersection.
I seem to recall that the county wants to add another lane to San Tomas south of El Camino but funding is an issue.
Why not paint a solid white line or, better, a double solid white line between the HOV lane and the regular lane through the merge area? Oh, maybe because the HOV lane is 3-7pm only. Not a very good reason.