Ramps that move traffic from one side of carriageway to another

[jakeroot]

This may fit better in the General Highway Talk board if mods want to move it.

Eastbound on I-90 in Bellevue, WA, there is a left-side HOV-only ramp that allows traffic in the HOV lane to access the I-405 exit ramp without having to change lanes multiple times:


I-90 / I-405 HOV ramps by Jacob Root, on Flickr

There is also a ramp that served the same purpose for westbound traffic, although it only served southbound 405 traffic. Aerial view of whole interchange showing both ramps. (edit: replaced picture showing both ramps).

The ramps were originally built in the 1990s as part of the final stage of I-90 construction across Lake Washington. The original freeway included reversible express lanes, and the ramps served to connect express lane users to I-405. When the express lanes were removed and replaced by light rail, the eastbound ramp (and most other express lane ramps in the corridor) were realigned to connect with the HOV lane (the westbound ramp always connected directly to HOV). This effectively created a 24/7 HOV exit for I-405 from eastbound I-90 (compared to the original design, where the ramp was only usable during the afternoon), although its only use now is to eliminate the need to change lanes to the right, as it simply connects to the general purpose exit. This was also the case before, as traffic could have exited the express lanes on the eastern edge of Mercer Island to access the 405 exit ramp, but this ramp made the maneuver much easier and safer, as there was no need to quickly weave across multiple lanes. For westbound traffic, the HOV ramp was similarly essential to ensure safer/quicker access to the express lanes, although it operated 24/7 as it directly connected to I-90's HOV lanes, which went a bit beyond the express lane entry point, to about halfway across Mercer Island.

I don't know if WSDOT would build such a ramp complex these days, but it is rather impressive. I suspect there are many HOV users who do not use the overpass, as there is no "time crunch" like there was before (you can change lanes whenever you want ahead of time as opposed to a very limited stretch of roadway before). But it is helpful, and from my personal experience (extensive these days), there really is no peak-hour rush on I-90, so something is working well. Overall, the I-90 HOV corridor is rather impressive, with direct access to Mercer Island, Bellevue Way, I-405 (technically, as discussed above), and 142nd in Bellevue.


So: any similar designs elsewhere in the world that really only serve to reduce lane-changing?

For the record, I am not thinking of things like the basketweave interchanges on Ontario's 401 freeway, as those are completely essential to ensure access between the local and express lanes -- basically the original purpose of the ramp I posted above.

[Mapmikey]

There may be a setup in Rockville MD on I-270 SB approaching I-270 SPUR that meets your definition.

The left-most lane is HOV only 6-9 M-F and open to all non-truck traffic otherwise and therefore a left lane user can stay left to reach I-270 SPUR (to reach I-495 East/South) without having to slide over multiple lanes.

https://goo.gl/maps/RLxNvLYHkdmFixvH8

Another potential example used to exist on I-495 north at I-66 where the right hand exit was built to eliminate a substantial amount of people moving 4 lanes to the left to reach I-66 WB.  This was all removed with the construction of the HOT lanes through here.

https://goo.gl/maps/a37MGiRgooSEAHDb6

[SkyPesos]

There's 2 of them I can think of in the Columbus area of Ohio
- I-71 SB to Stringtown Rd (exit 100): Moves Stringtown Rd exiting traffic to the far right, so they don't have to lane change against the entering I-270 traffic
- I-270 NB to Easton Way/OH 161 (exits 33 and 30): Moves Easton and OH 161 exiting traffic to the far right, so they don't have to lane change against the entering I-670 traffic.

[skluth]

This on/off reversible ramp at Fairfax County Parkway to the toll lanes in the middle of I-95 south of DC.

There are several ramps connecting the inner toll lanes of I-95/395/495 at Mixing Bowl.

There are a few others along the same lines along both the Beltway and further south on I-95.

Near me, the ramps connecting the HOT lanes on I-15 to CA 91 were recently built.

[SkyPesos]

Somewhat related, but how about two exit ramps from one freeway to another, but one of them is signed as an exit off the other freeway to reduce lane merging? Some I know of:

- I-170 NB to I-70 WB (exit 7B) and STL airport (exit 7C): You can technically get to both destinations using either ramp, but the dedicated exit ramp from I-170 NB makes it easier for airport traffic to exit from I-70 WB shortly after entering it, since the actual I-170 NB to I-70 WB ramp enters I-70 WB on the left.

- The Easton/OH 161 example I posted above also have two ramps from I-670, one to I-270 NB and the other to Easton Way and OH 161. Both enters I-270 at different sides (I-270 NB ramp in the middle, Easton/OH 161 ramp in the far right).

- I-270 WB to US 33/OH 161 WB and Avery-Muirfield Dr. Similar case as the two examples above.

[jakeroot]

There may be a setup in Rockville MD on I-270 SB approaching I-270 SPUR that meets your definition.

The left-most lane is HOV only 6-9 M-F and open to all non-truck traffic otherwise and therefore a left lane user can stay left to reach I-270 SPUR (to reach I-495 East/South) without having to slide over multiple lanes.

https://goo.gl/maps/RLxNvLYHkdmFixvH8

Another potential example used to exist on I-495 north at I-66 where the right hand exit was built to eliminate a substantial amount of people moving 4 lanes to the left to reach I-66 WB.  This was all removed with the construction of the HOT lanes through here.

https://goo.gl/maps/a37MGiRgooSEAHDb6

The only difference between these, and the example I posted, is that my example doesn't have any sort of dedicated ramps for both directions. Meaning, traffic eastbound on I-90 (in my OP) simply crosses over the carriageway and plugs into the single-occupancy exit, where they must fight those vehicles to merge onto the 405. The 405 has HOV lanes, but there is direct access to it. In both of your examples, the ramps are exclusive from roadway A to roadway B without fighting the other ramp.

There's 2 of them I can think of in the Columbus area of Ohio
- I-71 SB to Stringtown Rd (exit 100): Moves Stringtown Rd exiting traffic to the far right, so they don't have to lane change against the entering I-270 traffic
- I-270 NB to Easton Way/OH 161 (exits 33 and 30): Moves Easton and OH 161 exiting traffic to the far right, so they don't have to lane change against the entering I-670 traffic.

I think your second example is identical to one of the movements (southbound 405 to eastbound I-90, the right to left movement in my photo). Traffic can stay right and then reach the left side of the roadway (the HOV lanes), so they don't have to change over once they merge. This would be the same as the split from I-670, as it allows traffic to choose the correct side of the carriageway for what they want. The other ramp in my example (the left to right movement) is basically the exact same, just in reverse.

[jakeroot]

This on/off reversible ramp at Fairfax County Parkway to the toll lanes in the middle of I-95 south of DC.

There are several ramps connecting the inner toll lanes of I-95/395/495 at Mixing Bowl.

There are a few others along the same lines along both the Beltway and further south on I-95.

Near me, the ramps connecting the HOT lanes on I-15 to CA 91 were recently built.

Similar to Mapmikey's examples, the only reason these differ from my original post is that the off-ramp and on-ramps are both dedicated movements, whereas in my original post, one of the splits is dedicated, and the other is shared with general purpose traffic. So, traffic going eastbound on I-90 destined for 405 has their own dedicated off-ramp, but the merge to 405 is shared with the single-occupancy traffic as it simply merges into the regular exit before reaching 405.

[jakeroot]

Somewhat related, but how about two exit ramps from one freeway to another, but one of them is signed as an exit off the other freeway to reduce lane merging? Some I know of:

- I-170 NB to I-70 WB (exit 7B) and STL airport (exit 7C): You can technically get to both destinations using either ramp, but the dedicated exit ramp from I-170 NB makes it easier for airport traffic to exit from I-70 WB shortly after entering it, since the actual I-170 NB to I-70 WB ramp enters I-70 WB on the left.

- The Easton/OH 161 example I posted above also have two ramps from I-670, one to I-270 NB and the other to Easton Way and OH 161. Both enters I-270 at different sides (I-270 NB ramp in the middle, Easton/OH 161 ramp in the far right).

- I-270 WB to US 33/OH 161 WB and Avery-Muirfield Dr. Similar case as the two examples above.

In the first example, this is a bit different because both ramps are dedicated from start to finish (dedicated exits and entrances from both freeways).

The second example I already covered above, it's definitely right on the money.

The third example is just odd, I would think a single ramp with two lanes would have done the job well enough. It's still a bit different in that both splits are from the same side of the roadway. Still, what an odd setup.

[webny99]

I know it's a different situation, but when I read the thread title I thought of this ramp, connecting I-390 NB to NY 15:

[SkyPesos]

- I-270 WB to US 33/OH 161 WB and Avery-Muirfield Dr. Similar case as the two examples above.

The third example is just odd, I would think a single ramp with two lanes would have done the job well enough. It's still a bit different in that both splits are from the same side of the roadway. Still, what an odd setup.

Looking at AADT data of the area, it seems like that the AADT of the I-270 WB ramp signed for US 33/161 WB is 11,043, and the ramp signed for Avery-Muirfield Dr is signed for 12,565. Though not shown on this map for some reason, the ramp from US 33/161 WB to Avery-Muirfield Dr (which includes the traffic coming from the separate I-270 WB ramp) is 17,648 when clicking on the square. My best guess for this is that a huge majority of the cars using the WB Avery-Muirfield Dr exit are coming from I-270 WB (12565/17648 is 71.2%, and I think it's reasonable to assume that close to 0 drivers using the I-270 WB ramp signed for Avery-Muirfield are actually continuing on US 33/161 WB) that they found it worthwhile to build a separate ramp for I-270 WB to Avery-Muirfield traffic and lessen merging into the far right lane from the rest of the US 33/161 traffic. Then the question after that is why they didn't they just go with a fully separated C/D lane, which I don't know either.

[jakeroot]

I know it's a different situation, but when I read the thread title I thought of this ramp, connecting I-390 NB to NY 15:

I've seen a couple like that where I don't understand why it was done (here for example), but at least there it makes sense. With the river and loop ramp and all.

[jakeroot]

- I-270 WB to US 33/OH 161 WB and Avery-Muirfield Dr. Similar case as the two examples above.

The third example is just odd, I would think a single ramp with two lanes would have done the job well enough. It's still a bit different in that both splits are from the same side of the roadway. Still, what an odd setup.

Looking at AADT data of the area, it seems like that the AADT of the I-270 WB ramp signed for US 33/161 WB is 11,043, and the ramp signed for Avery-Muirfield Dr is signed for 12,565. Though not shown on this map for some reason, the ramp from US 33/161 WB to Avery-Muirfield Dr (which includes the traffic coming from the separate I-270 WB ramp) is 17,648 when clicking on the square. My best guess for this is that a huge majority of the cars using the WB Avery-Muirfield Dr exit are coming from I-270 WB (12565/17648 is 71.2%, and I think it's reasonable to assume that close to 0 drivers using the I-270 WB ramp signed for Avery-Muirfield are actually continuing on US 33/161 WB) that they found it worthwhile to build a separate ramp for I-270 WB to Avery-Muirfield traffic and lessen merging into the far right lane from the rest of the US 33/161 traffic. Then the question after that is why they didn't they just go with a fully separated C/D lane, which I don't know either.

And that's the interesting thing to me, it seems to be an on-the-cheap C/D setup but having the second ramp come in so late that it effectively acts as a dedicated exit to Avery-Muirfield Dr. But then I have to wonder why not have, say, a single or double white line right up to the exit for that outer ramp instead of 1400 feet of exit-only dashes. I guess it allows traffic to switch into the right-most exit lane, but then they could easily change lanes after the exit...IDK.

[webny99]

I know it's a different situation, but when I read the thread title I thought of this ramp, connecting I-390 NB to NY 15:

I've seen a couple like that where I don't understand why it was done (here for example), but at least there it makes sense. With the river and loop ramp and all.

And most importantly, to align with East River Rd which continues west from that intersection. My guess would be that there's similar reasoning in the WA example you posted, except in reverse: traffic on Maplewood can get on I-5 with zero turns instead of a right and quick left (which can be gnarly if there's heavy volumes).

[wanderer2575]

In Toledo, the southbound I-75 "exit" to Stickney Avenue/Lagrange Street splits off from the ramp to southbound I-280, merges with the ramp from northbound I-280, and merges back onto I-75.  This puts Stickney/Lagrange traffic in the right lane for the actual exit 1/4 mile farther along, instead of that exiting traffic having to weave through the traffic entering from I-280.

https://goo.gl/maps/rrbASfSsKnAczyGK8

[mrsman]

I think the I-395 ramps in VA over Turkeycock Run are similar:

https://www.google.com/maps/place/Turkeycock+Run/@38.8101747,-77.1530926,17z/data=!4m5!3m4!1s0x89b7b306793e18d3:0xc89f71b2e05f6b5a!8m2!3d38.8160163!4d-77.1510326

It allows freeway traffic to exit onto the right to enter the express lane and in the SB direction it allows express lane traffic to enter the freeway from the right, in order to reach upcoming exits like Edsall and the Beltway.  In the days before the Beltway HOT lanes, it allowed for certain express buses from the Beltway to take I-395 regular lanes to then reach the express lanes before Pentagon and Downtown DC.

The express lane was once bus only, then it became HOV, then it became express lanes.  For a long time, (as discussed in the Mid-Atlantic forum*), the Arlington section of the express lanes were free but HOV only while the southern section of the express lanes allowed HOV or toll but all required transponders.  These ramps provided for connection between the express lanes and the regular lanes and provided specific access for folks who met the express lane conditions on one section of the express lanes, but not the other.

* In brief, this silliness was the result of certain lawsuits by Arlington to maintain HOV restriction over their portion of the road.  The main portion of the express lanes were converted from HOV to HOT in order to allow for more users, but Arlington questioned whether congestion mitigation measures would be impacted by allowing Transurban to operate a private concession on the highway.  Fortunately, it was eventually overturned with the I-395 express lane project allowing for any vehicle with a toll transponder to ride on the road.

https://www.thetruthaboutcars.com/2009/08/arlington-sues-virginia-over-hot-lanes/

[CardInLex]

In Downtown Louisville on I-65 leading to the Abraham Lincoln Bridge and coming from the John F. Kennedy Bridge there are ramps that take traffic from/to the far right side of the roadway to/from the far right side of the bridges while mainline continues in the center. So, from left to right you have: thru lane, thru lane, exit/entrance lane, exit/entrance lane, exit/entrance lane, thru lane. Designed that way traffic on 65 can access the exit without having to cross over the joining traffic (southbound) and traffic entering 65 can access mainline without having to cross over exiting traffic (northbound).

https://goo.gl/maps/mzDJ1BSY1B3k2sZq6


Just to the east, on I-64, the ramp from Story Ave has a ramp that takes you from the far right side to of I-64 and drops you into the far right side of I-65. Without it a vehicle would theoretically have to merge across two lanes to access I-65. But, this isn't exactly the same situation.

https://goo.gl/maps/miN5Geq2eFgPK9Ry8

[jakeroot]

In Toledo, the southbound I-75 "exit" to Stickney Avenue/Lagrange Street splits off from the ramp to southbound I-280, merges with the ramp from northbound I-280, and merges back onto I-75.  This puts Stickney/Lagrange traffic in the right lane for the actual exit 1/4 mile farther along, instead of that exiting traffic having to weave through the traffic entering from I-280.

https://goo.gl/maps/rrbASfSsKnAczyGK8

That's very cool! Like a couple other examples, basically a C/D road, but without the actual separate roadway (well, at least for the last 1100 feet).

[jakeroot]

I think the I-395 ramps in VA over Turkeycock Run are similar:

https://www.google.com/maps/place/Turkeycock+Run/@38.8101747,-77.1530926,17z/data=!4m5!3m4!1s0x89b7b306793e18d3:0xc89f71b2e05f6b5a!8m2!3d38.8160163!4d-77.1510326

It allows freeway traffic to exit onto the right to enter the express lane and in the SB direction it allows express lane traffic to enter the freeway from the right, in order to reach upcoming exits like Edsall and the Beltway.  In the days before the Beltway HOT lanes, it allowed for certain express buses from the Beltway to take I-395 regular lanes to then reach the express lanes before Pentagon and Downtown DC.

The express lane was once bus only, then it became HOV, then it became express lanes.  For a long time, (as discussed in the Mid-Atlantic forum*), the Arlington section of the express lanes were free but HOV only while the southern section of the express lanes allowed HOV or toll but all required transponders.  These ramps provided for connection between the express lanes and the regular lanes and provided specific access for folks who met the express lane conditions on one section of the express lanes, but not the other.

* In brief, this silliness was the result of certain lawsuits by Arlington to maintain HOV restriction over their portion of the road.  The main portion of the express lanes were converted from HOV to HOT in order to allow for more users, but Arlington questioned whether congestion mitigation measures would be impacted by allowing Transurban to operate a private concession on the highway.  Fortunately, it was eventually overturned with the I-395 express lane project allowing for any vehicle with a toll transponder to ride on the road.

https://www.thetruthaboutcars.com/2009/08/arlington-sues-virginia-over-hot-lanes/

Great example! This is virtually identical to my original post, although identical to the original setup of I-90, where there was a separate reversible roadway (again, just like your example).

I think I recall the HOV/express lane confusion early on when my mother first moved to NoVA in late 2017. I remember using the center span of the George Mason Bridge to more easily access Route 1, as it allowed for direct access to the left side of 395 where traffic could then easily exit onto Route 1. But there were no restrictions on that center span for single-occupancy vehicles, so it was a kind of shortcut. Judging from GSV, this may still be the case.

At any rate, I absolutely remember all of the construction along Route 1 when I first started heading that way, but not having a vehicle out there (WMATA for the win), I haven't been able to see the finished product for myself.

[jakeroot]

In Downtown Louisville on I-65 leading to the Abraham Lincoln Bridge and coming from the John F. Kennedy Bridge there are ramps that take traffic from/to the far right side of the roadway to/from the far right side of the bridges while mainline continues in the center. So, from left to right you have: thru lane, thru lane, exit/entrance lane, exit/entrance lane, exit/entrance lane, thru lane. Designed that way traffic on 65 can access the exit without having to cross over the joining traffic (southbound) and traffic entering 65 can access mainline without having to cross over exiting traffic (northbound).

https://goo.gl/maps/mzDJ1BSY1B3k2sZq6


Just to the east, on I-64, the ramp from Story Ave has a ramp that takes you from the far right side to of I-64 and drops you into the far right side of I-65. Without it a vehicle would theoretically have to merge across two lanes to access I-65. But, this isn't exactly the same situation.

https://goo.gl/maps/miN5Geq2eFgPK9Ry8

First example definitely looks like a collector/distributor roadway, but a really good one. In fact, pretty much everything I'm looking at seems brand new, was this all just rebuilt?

Second example is pretty cool, not quite the same thing technically, but still neat.

[wriddle082]

In Columbia, SC, in the current configuration of Malfunction Junction, at the I-126 western terminus, there is a ramp marked with the I-26 exit number 107 for I-20.  Whether you follow that ramp in the right lane or stay in the left or center lanes to proceed on I-26 west, you'll still be on I-26 west.  The ramp to the right goes around the flyover landing for the I-26 westbound through traffic, while the left and center lanes go under the flyover, thus allowing the I-26 westbound lanes to merge into the center of a brief five-lane carriageway (that far right lane ultimately becomes exit only for I-20 east).  Without this setup, traffic from 126 wishing to access 20 would potentially have to cross two or three lanes of I-26 westbound traffic in less than a half mile to access the I-20 exits.

They have officially broken ground on a rebuild of this entire interchange and portions of the highways leading to it, so I'd say this setup will be mostly going away in favor of separate local and express carriageways for I-26, in addition to a turbine interchange for 20/26 to replace the horrible cloverleaf w/o C/D roads.  Whole thing will take >10 years.

[Occidental Tourist]

I think the exit ramps from the 163 to the I-15 Express Lanes and from the I-15 Express Lanes to the 163 qualify.

[ErmineNotyours]

Another "somewhat similar but not the same" example: the trumpet interchange of I-90 and I-82.  Usually trumpet interchanges are economical because you only have to build one grade separation, but here traffic which had to go around the loop (from the east) then has to go over another bridge to go over traffic from the west.  It deposits this traffic on the right lane instead of the left, and maybe traffic studies said this was important enough to warrant the expense of an additional bridge.

[Occidental Tourist]

Another "somewhat similar but not the same" example: the trumpet interchange of I-90 and I-82.  Usually trumpet interchanges are economical because you only have to build one grade separation, but here traffic which had to go around the loop (from the east) then has to go over another bridge to go over traffic from the west.  It deposits this traffic on the right lane instead of the left, and maybe traffic studies said this was important enough to warrant the expense of an additional bridge.

That's really interesting.  It looks like the interchange was built sometime after 1971, but I can't tell if the additional bridge was part of the original design.  It appears the additional bridge had been built by no later than 1981 if it wasn't part of the original construction.

[ErmineNotyours]

Another "somewhat similar but not the same" example: the trumpet interchange of I-90 and I-82.  Usually trumpet interchanges are economical because you only have to build one grade separation, but here traffic which had to go around the loop (from the east) then has to go over another bridge to go over traffic from the west.  It deposits this traffic on the right lane instead of the left, and maybe traffic studies said this was important enough to warrant the expense of an additional bridge.

That's really interesting.  It looks like the interchange was built sometime after 1971, but I can't tell if the additional bridge was part of the original design.  It appears the additional bridge had been built by no later than 1981 if it wasn't part of the original construction.

Looks like early 70s construction on the additional bridge.  By the mid-70s they were building the railings as Jersey barriers.  The state stamps the date into the bridges, but then they slap guard rails over them so we can't read them. 

The reason for dumping traffic on the right instead of the left is that traffic from the west forms two lanes, forming an early passing lane.

[Bruce]

Another "somewhat similar but not the same" example: the trumpet interchange of I-90 and I-82.  Usually trumpet interchanges are economical because you only have to build one grade separation, but here traffic which had to go around the loop (from the east) then has to go over another bridge to go over traffic from the west.  It deposits this traffic on the right lane instead of the left, and maybe traffic studies said this was important enough to warrant the expense of an additional bridge.

That's really interesting.  It looks like the interchange was built sometime after 1971, but I can't tell if the additional bridge was part of the original design.  It appears the additional bridge had been built by no later than 1981 if it wasn't part of the original construction.

That section of I-82 opened in 1971 and definitely included the extra crossing in the original design. This was in the 1973 Washington highway map: