The yin-yang interchange?

[tradephoric]

This interchange is near Myrtle Beach and has a unique design:

[Brandon]

Looks like the old Telegraph Road (US-24) and I-94 interchange.

[tradephoric]

Looks like the old Telegraph Road (US-24) and I-94 interchange.

Thanks Brandon!  The old interchange at US-24 & I-94 was completely free-flowing and required no traffic signals along the arterial while the new 'supposedly' innovative SPUI interchange requires a 3-phase traffic signal that stops all directions of traffic.  Looking at the arterial what interchange would you rather drive? 

I believe they were rehabilitating one of the off-ramp in the SPUI arterial (which partly explains the long queue extending towards the freeway for WB 94) but it doesn't change the simple fact that traffic signals inherently STOP traffic.

Old 'yin-yang' interchange at US-24 & I-94:


New SPUI design (built around 2005) at US-24 & I-94:

[InterstateNG]

The old interchange at Telegraph was awful.  Underpowered for the traffic it serves and the radii on those curves were lousy.  I'd rather drive the SPUI.  Is far from the impediment you make it out to be.

[hbelkins]

Plus those left exits and entrances...

[vdeane]

The old interchange at Telegraph was awful.  Underpowered for the traffic it serves and the radii on those curves were lousy.  I'd rather drive the SPUI.  Is far from the impediment you make it out to be.

I'll take a tight radius curve over a traffic light any day of the week.

[InterstateNG]

Plus those left exits and entrances...

Uphill and blind.

[tradephoric]

Rob Morosi - "The SPUI design is much safer, because of longer exit ramps with increased storage that eliminate the backup on the freeway. And when you exit I-94 to Telegraph, with the SPUI design, the decision of which direction you want is made on the ramp, at a slower speed. Before, that decision was made on mainline I-94 itself."



Way to prevent backups onto the freeway...

[NE2]

Looks like a backup on the exit lanes. Less than ideal, but not horrible.

[SSOWorld]

Looks like a backup on the exit lanes. Less than ideal, but not horrible.

Doesn't look to be impacting mainline traffic as the back-up is in dedicated exit lanes.

[catch22]

Plus those left exits and entrances...

Uphill and blind.

And with relatively short acceleration lanes.  I use this interchange a few times a week, and am glad to be rid of the left entrance/exit ramps.

[tradephoric]

The old interchange at Telegraph was awful.  Underpowered for the traffic it serves and the radii on those curves were lousy.  I'd rather drive the SPUI.  Is far from the impediment you make it out to be.

For any individual traffic signal, you can argue that's it's not that big of an impediment for a driver to come to stop.  However, multiply that thinking by 30-40 traffic signals along a 10 mile coordinated stretch and you're driving along an arterial with poorly placed traffic signals getting stopped at every other red light. 

I agree that the left entrance/exit ramps are less than ideal in this design.  Likely, this alone will prevent this type of interchange from gaining popularity. 

[kphoger]

My brain is shorting out right now.  What are the practical differences between the yin-yang interchange and the double spread trumpet interchange?

[InterstateNG]

The old interchange at Telegraph was awful.  Underpowered for the traffic it serves and the radii on those curves were lousy.  I'd rather drive the SPUI.  Is far from the impediment you make it out to be.

For any individual traffic signal, you can argue that's it's not that big of an impediment for a driver to come to stop.  However, multiply that thinking by 30-40 traffic signals along a 10 mile coordinated stretch and you're driving along an arterial with poorly placed traffic signals getting stopped at every other red light.

Hypothetically, sure.  Specifically on Telegraph?  Not so much.  Anyone who has driven from Eureka to Square Lake knows the 3-4 places you're likely to catch a red.

[NE2]

My brain is shorting out right now.  What are the practical differences between the yin-yang interchange and the double spread trumpet interchange?

The former has a single thread here to define it and the latter doesn't even have that?

[tradephoric]

Telegraph Road is the poster child for innovative intersection designs.  That's what makes the SPUI at I-94 & Telegraph seem so out of place since the SPUI naturally leads to poor 2-way signal progression (leads to the "half mile"  signals that are so hard to coordinate).  If MDOT is willing to construct a SPUI along one of the most innovative arterials in America then there's little hope for the rest of the country.  Phoenix's widespread use of SPUI's or Toronto's widespread use of Parclo A4 interchanges are just some examples of how freeway interchange designs are leading to poor traffic signal progression throughout our cities. 

[InterstateNG]

(At the risk of straying too far off topic)

Except you always got stopped at Van Born before the SPUI was constructed.  MDOT deliberately mistimes a few signals on Telegraph to slow traffic down.  The light at 15 Mile comes to mind.  Whether MDOT should be doing that is a different matter.

Telegraph is hardly unique:  Mound from 18 1/2 down to 8 Mile is similar

[johndoe]

I feel like I should add a disclaimer that I know nothing about this location     But what an expensive project!  Move both directions of the interstate and add a gigantic bridge and walls for a SPUI?!  In fairness, I think I see a lane is closed in that google earth picture, maybe that's not a fair representation of traffic haha!  At least it looks really cool:  http://goo.gl/maps/1Ao9j


Maybe they realigned mainline for a good reason?  Here's a goofy idea I mocked up in a very technical program known as Paint =)  I'm sure you can decipher the colors.

It would keep you from realigning mainline, provide all right entrances/exits, and prevent any signalization.  And I'd be willing to bet it'd STILL be less bridge than a SPUI!   

[Alps]

24/94 was my favorite interchange growing up. I got an old Detroit map in 92 or 94 and immediately found that one. We drove right by it, I don't think we took it, in 1996 or 7, and I was thrilled.

[InterstateNG]

Yeah, those older maps of the different parts of the Detroit metro were really cool.  Especially the one with the detailed view of all the wacky interchanges on 94 and 75 on the back.

[tradephoric]

I feel like I should add a disclaimer that I know nothing about this location     But what an expensive project!  Move both directions of the interstate and add a gigantic bridge and walls for a SPUI?!  In fairness, I think I see a lane is closed in that google earth picture, maybe that's not a fair representation of traffic haha!  At least it looks really cool:  http://goo.gl/maps/1Ao9j


Maybe they realigned mainline for a good reason?  Here's a goofy idea I mocked up in a very technical program known as Paint =)  I'm sure you can decipher the colors.

It would keep you from realigning mainline, provide all right entrances/exits, and prevent any signalization.  And I'd be willing to bet it'd STILL be less bridge than a SPUI!   

They spent a lot of money on the "Superbowl bridge"  (I guess those big blue arches were suppose to resemble football lacings, makes you wonder why the bridge is painted blue).  Had they gone with a less costly bridge design, possibly a full-blown freeway-to-freeway interchange could have been constructed for the same amount of money (something similar to this design, but with the freeway bridges realigned closer together since I believe those bridges needed to be replaced anyways).   I'd rather see the 3-4 million extra spent on flyover ramps than making a bridge look like a football.

[InterstateNG]

Painted blue because the Lions wear blue.  Closest they'll get to the Super Bowl.

Had they gone with a less costly bridge design, possibly a full-blown freeway-to-freeway interchange could have been constructed for the same amount of money (something similar to this design, but with the freeway bridges realigned closer together since I believe those bridges needed to be replaced anyways).   I'd rather see the 3-4 million extra spent on flyover ramps than making a bridge look like a football.

You'll pardon my presumption, but I quetion how familiar you are with the area surrounding the interchange.  The plan you suggest, with a new overpass required at Van Born and plenty of property acquisition, including a cemetery in the NW quadrant would cost more than 3-4 million.  The upgraded interchange works as constructed.

[tradephoric]

You'll pardon my presumption, but I quetion how familiar you are with the area surrounding the interchange.

You'll agree with me that a SPUI was a bad design for this interchange.

[Anthony_JK]

You'll pardon my presumption, but I quetion how familiar you are with the area surrounding the interchange.

You'll agree with me that a SPUI was a bad design for this interchange.

Sorry, but I don't.

Considering the main goal of narrowing the I-94 ROW to normal freeway grade and that we are dealing with an arterial, not a freeway...the SPUI design works perfectly for me. How do you know the backup isn't due to an accident on the cross street???  Plus, temporarily lengthing the left turn traffic cycle for the oncoming exit ramp traffic (or, simply the use of a traffic cop) resolves that  backup easily.

[Brandon]

You'll pardon my presumption, but I quetion how familiar you are with the area surrounding the interchange.

You'll agree with me that a SPUI was a bad design for this interchange.

Sorry, but I don't.

Considering the main goal of narrowing the I-94 ROW to normal freeway grade and that we are dealing with an arterial, not a freeway...the SPUI design works perfectly for me. How do you know the backup isn't due to an accident on the cross street???  Plus, temporarily lengthing the left turn traffic cycle for the oncoming exit ramp traffic (or, simply the use of a traffic cop) resolves that  backup easily.

If you look at the photograph, there's no traffic south of I-94 on southbound Telegraph.  I sincerely doubt it is due to an accident at a cross street, or on Telegraph for that matter.  I'll also disagree withe the SPUI being the best idea there.  However, it's about as dysfunctional as the previous interchange, but in a different way.  It could have been better thought out, IMHO.  However, if that SPUI is among the worst things MDOT has come up with for an interchange, then they're still light years ahead of IDOT (which seems to believe traffic should come to a full and complete stop as often as possible).