Right turns, unramped

[lepidopteran]

Ever notice how a right-hand turn, usually from a freeway off-ramp, is sometimes "downgraded" from a merge-type ramp to an ordinary right-angle right turn?

Reasons for doing so may vary.  Sometimes, the ramp was underpowered to begin with, you had to yield anyway, and it can be harder to turn your neck to look 135° than 90°.  Or maybe the ramp was sufficient to merge, but increased traffic counts and stop-and-go conditions over time have made merging impractical.

One example was when redid the ramps from the I-495 Capital Beltway "Outer Loop" to University Blvd. near Silver Spring, MD.  The looping off-ramp was removed, and traffic going either way on University Blvd. was now directed to a traffic signal.  But the right turn "ramp" to University was replaced with double right-turn lanes at the signal.  This made sense, since it was difficult to see traffic coming across the bridge over the Beltway when looking at a sharp angle.

[kurumi]

Sometimes this is done to aid pedestrians: http://www.contracostatimes.com/news/ci_24705268/road-planners-want-slow-down-your-turn-and

[vtk]

This was just done for the entrance ramp from Livingston Ave to I-70 WB. I'm pretty sure this was done to improve safety crossing Livingston Ave, as a bikeway now crosses there.

I think in some cases the traffic hasn't changed, but engineers just aren't as enthusiastic about channelized right turns as they once were, so when the intersection is rebuilt, they decide it never needed to be channelized in the first place.

[hotdogPi]

Graveyard on MA 128 northbound (not I-95 at this point) between exits 25 and 24. It doesn't have an exit number.

[vdeane]

The ramps from Hylan Dr to I-390 north are like this.  Normally when you have separate ramps for each direction and no stopping, you don't have 90 degree turns, but that's how NYSDOT constructed them.  Although there were rumors of a street that would have gone straight into one of the ramps, and the other used to serve both directions.

[Mr. Matté]

While I was making a KML file for the PA 115 Wiki article, I noticed that between 2010 and 2012, PennDOT removed the channelized ramp from northbound 115-->I-80 east and southbound 115-->I-80 west and replaced with right turns.

https://maps.google.com/?ll=41.076512,-75.576679&spn=0.006769,0.013937&t=k&z=17 (old ramps ROWs still visible)

Was it due to some requirement that people who get off at the exit have the option to immediately get back on? It's certainly not because of merging traffic on the ramps or ped/bike facilities.

[vtk]

While I was making a KML file for the PA 115 Wiki article, I noticed that between 2010 and 2012, PennDOT removed the channelized ramp from northbound 115-->I-80 east and southbound 115-->I-80 west and replaced with right turns.

https://maps.google.com/?ll=41.076512,-75.576679&spn=0.006769,0.013937&t=k&z=17 (old ramps ROWs still visible)

Was it due to some requirement that people who get off at the exit have the option to immediately get back on? It's certainly not because of merging traffic on the ramps or ped/bike facilities.

This oone might have been intended to allow those movements to achieve greater speed before meeting the freeway mainline.

[PHLBOS]

Graveyard on MA 128 northbound (not I-95 at this point) between exits 25 and 24. It doesn't have an exit number.

What's even weirder about that stretch of 128 (at the Peabody/Danvers line) is that there appears to be traces of an asphalt sidewalk along that northbound stretch.  One has to wonder when this stretch of highway was first built (late 40s/early 50s) did it indeed include a sidewalk for most of the way?  Note: any traces of such sidewalks at the 114 interchange (Exit 25A-B) were likely taken out when it was modified to its current configuration in the late 50s/early 60s (the same time the North Shore Shopping Center (now North Shore Mall) was built).

[hotdogPi]

There is another place where this happens on MA 128, just the slightest bit away from Exit 21.

[NE2]

fulbos and 1 both fail.

[cpzilliacus]

One example was when redid the ramps from the I-495 Capital Beltway "Outer Loop" to University Blvd. near Silver Spring, MD.  The looping off-ramp was removed, and traffic going either way on University Blvd. was now directed to a traffic signal.  But the right turn "ramp" to University was replaced with double right-turn lanes at the signal.  This made sense, since it was difficult to see traffic coming across the bridge over the Beltway when looking at a sharp angle.

The structure that carries Md. 193 (University Boulevard East) over I-495 in Silver Spring (ZIP Code 20901) may be the oldest structure that is nearly unchanged from before the opening of the full Beltway (though not for long, as it will be redecked in the very near future). 

The segment of I-495 between Md. 193 and Md. 97 (Georgia Avenue) was opened to traffic several years before the full road was completed in 1964, and the ramp from westbound 193 to the Outer Loop was open to traffic back then, so the bridge had to have been there from the start for that movement (but not the Inner Loop, as all traffic was forced to exit onto 193 eastbound) before the bridge.

Maryland SHA has been removing cloverleaf-style loop ramps when their presence create weaving traffic patterns (there are two left on Maryland's part of the Capital Beltway, both in Prince George's County, at "secret" Md. 295 (Baltimore-Washington Parkway) and Md. 4 Pennsylvania Avenue.  Both of those interchanges need to be reconstructed, though they will cost a lot of money, and the one at the Parkway must involve the National Park Service.

[PHLBOS]

There is another place where this happens on MA 128, just the slightest bit away from Exit 21.

Here's a better view of the Wayside Drive intersection w/128. 

GSV close-up of the two ramps

Given its close proximity to Trask Lane (Exit 21 just east of the intersection); I'm surprised that the state still hasn't blocked off this entrance.  MA 128 is supposed to be a limited-access highway in this area.

[froggie]

Maryland SHA has been removing cloverleaf-style loop ramps when their presence create weaving traffic patterns (there are two left on Maryland's part of the Capital Beltway, both in Prince George's County, at "secret" Md. 295 (Baltimore-Washington Parkway) and Md. 4 Pennsylvania Avenue.

Beltway still has loop weaves at both Branch Ave (Outer Loop) and St. Barnabas Rd (both directions).  Even with at-grade intersections on St. Barnabas proper, that interchange is still functionally a full cloverleaf as far as the Beltway is concerned.

[cpzilliacus]

Beltway still has loop weaves at both Branch Ave (Outer Loop) and St. Barnabas Rd (both directions).  Even with at-grade intersections on St. Barnabas proper, that interchange is still functionally a full cloverleaf as far as the Beltway is concerned.

SHA got rid of the one that was causing severe P.M. peak period problems, from Inner Loop (I-95 S) to southbound Md. 5 (though the flyover that replaced it has not worked especially well).

You are correct about Md. 414 (Exit 4), though I did not include that interchange because it is not part of the "original" Beltway.  When the Beltway was complete in 1964, the interchange was signed as Exit 37A, and there was one exit ramp from the Outer Loop to Md. 414, and one entrance ramp from Md. 414 to the Inner Loop (perhaps so residents of Virginia would have easy access to the harness racing track at Rosecroft?).

When the road opened in 1964, this was a partial interchange only

[PHLBOS]

The US 422/PA 23 interchange near Valley Forge within the last few years lost one of its cloverleaf ramps (from US 422 West to PA 23 West) in favor of a single exit ramp to both directions of PA 23.

Current US 422/PA 23 interchange

How the interchange used to look circa 2008

Note: the current 422 eastbound exit ramp to PA 23 will be reconfigured in the future.  The reconfigured exit ramp will flyover US 422 and connect PA 23 where the eliminated cloverleaf ramp once stood.

Back to MA:

Both the MA 62 & MA 35 interchanges w/MA 128 (Exits 22 & 23) are now diamonds vs. a tight partial and full cloverleafs respectively.

Current MA 128 interchanges w/MA 35 & 62

Same interchages circa 2005

[PurdueBill]

The end of the I-77 SB to OH 18 WB ramp was changed from a yield/merge to a stop sign/right turn a few years ago due to its closeness to the Crystal Lake Rd. right-turn lane and congestion/sideswipes/other problems.   One trace of striping from the old way is still visible.  Is that the idea of thing the OP was getting at?

[briantroutman]

I suppose this isn't exactly the same thing but related. I noticed this interchange on US 322 in Milroy which is otherwise a classic trumpet except that the two non-looping ramps meet the intersecting road at 90° like a diamond rather than gently curving to a merge point. That allows you to make an easier U-turn by exiting and making a left (or change your mind and re-enter if you didn't mean to exit), but beyond that, I don't see the point. And I've seen other interchanges like this elsewhere.

Is there any good reason (particularly in a situation like this–low-volume interchange and no pedestrians) not to curve and bank the ramps toward their ultimate destination?

https://maps.google.com/?ll=41.076512,-75.576679&spn=0.006769,0.013937&t=k&z=17 (old ramps ROWs still visible)

Was it due to some requirement that people who get off at the exit have the option to immediately get back on? It's certainly not because of merging traffic on the ramps or ped/bike facilities.

This oone might have been intended to allow those movements to achieve greater speed before meeting the freeway mainline.

That doesn't make sense to me because I'd think you would be able to achieve greater speed if you didn't have to slow down for a sharp 90° elbow. I can't see any advantage other than being able to re-enter the opposing on-ramp easily.

In fact, if they're going to have those ramps meet at a right angle like that, they might as well delete the two loop ramps, reduce PA 115 to one lane in each direction (it is on either side of the interchange area anyway), and install channelized left turns for the two on-ramps.

[Beeper1]

MA-2 has a few of these in the Leominster/Fichburg area. Abbott Ave, Mt. Elam Road, and I think one more each intersect at right angles. 

[Alps]

There is another place where this happens on MA 128, just the slightest bit away from Exit 21.

Here's a better view of the Wayside Drive intersection w/128. 

GSV close-up of the two ramps

Given its close proximity to Trask Lane (Exit 21 just east of the intersection); I'm surprised that the state still hasn't blocked off this entrance.  MA 128 is supposed to be a limited-access highway in this area.

Except this topic isn't about right turns from freeways, it's about removal of formerly channelized right turns.

[hotdogPi]

Except this topic isn't about right turns from freeways, it's about removal of formerly channelized right turns.

What happened is that I remembered a thread that what I was trying to talk about, searched, thought this was the thread, and posted in it. I'm not sure which one it was supposed to be posted in though. If you find it (it should be from around the new year), you can move all discussion relating to right turns from freeways to that thread.

[Bitmapped]

This happened to the ramps from US 35 WB to SR 7 at Gallipolis, OH.  This was a partial folded diamond and the inside ramps had channelized turns that were barricaded off in the past couple years.  I presume ODOT was trying to eliminate a weaving-type situation on SR 7.

Here's a Google Map: http://goo.gl/maps/htFjV The original ramps are still in place, just blocked by Jersey barriers.

[vtk]

https://maps.google.com/?ll=41.076512,-75.576679&spn=0.006769,0.013937&t=k&z=17 (old ramps ROWs still visible)

Was it due to some requirement that people who get off at the exit have the option to immediately get back on? It's certainly not because of merging traffic on the ramps or ped/bike facilities.

This oone might have been intended to allow those movements to achieve greater speed before meeting the freeway mainline.

That doesn't make sense to me because I'd think you would be able to achieve greater speed if you didn't have to slow down for a sharp 90° elbow. I can't see any advantage other than being able to re-enter the opposing on-ramp easily.

Aside from that initial 90 degree turn, the ramps now have less curvature.  My theory on this situation is, by lessening the curvature in the middle of the ramps, drivers are no longer limited to a lower speed for a significant length of the ramp as they were before.

[froggie]

Is there any good reason (particularly in a situation like this–low-volume interchange and no pedestrians) not to curve and bank the ramps toward their ultimate destination?

I can think of a few reasons why a trumpet might be designed like this:

- Limited right-of-way.
- Intersection spacing to the "downwind" intersection on the side road.
- Provision for a future extension of the side road.

Not sure if any of these apply in your Pennsylvania example, but they'd be possible reasons.

[jakeroot]

Interesting topic to me, so I'm gonna bump it.

A few examples in the Seattle metro area:

This one is I-90 at Lakemont Blvd. The slip lane from I-90 E was shortened down to a right-angle two-lane stop. Lakemont used to end at Newport but when it was extended circa 2001, they decided turning traffic would increase at the Newport/Lakemont intersection, so they trimmed down the slip lane so it didn't interfere with the new slip lane. I know that sounds sort of confusing, but when you look at the imagery, it will make sense:

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Another interesting change in geometry is at 48th & SR-18. It was a sort of Parclo interchange thing before it was changed in 2006-2007. The slip ramps toward 48th originally were much more curved then they used to be, especially the slip ramp from SR-18 westbound towards 48th eastbound.

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[andrewkbrown]

I-75 southbound ramp to Galbraith Road in Cincinnati, which used to wye at the intersection. The right turn lane used to run on a ramp alongside the guard rail, left turn lane was separate, with an island in the middle until around 2008 when they changed it to this current configuration.

https://maps.google.com/maps?ll=39.211919,-84.462641&spn=0.000844,0.001321&gl=us&t=h&layer=c&cbll=39.211915,-84.462968&panoid=vwikG0V6lWXnAKhEI11VSA&cbp=12,47.24,,0,6.06&z=20