I-75 Mega Project to Include Diverging Diamond Interchanges at 14 Mile, Big Beaver

At the end of the 2020 construction season M-DOT will complete two new Diverging Diamond Interchanges [[DDIs). These interchanges are much like the interchange at I-75 and University, with the exception that I-75 is under the bridge at University, and these new DDI's will have I-75 going on the bridge. No more A's and B's at exit 65 and 69, they'll only have one exit with no letters!

DDI's are cited as being much safer and providing better traffic flow because they eliminate the number of turns and completely eliminate left-hand turns.

Here are the drawings for it:

14 Mile
Attachment 37729

Big Beaver [[16 Mile)
Attachment 37730

I'm not really looking forward to the chaos over the next few months.

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Originally Posted by O3H

I'm not really looking forward to the chaos over the next few months.

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Great news, they're finally "fixing our roads"!

It's going to cause chaos during construction and spending $2 billion on highways isn't my favorite, but diamond interchanges are a vast improvement over what is there in both locations now.

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Originally Posted by EGrant

It's going to cause chaos during construction and spending $2 billion on highways isn't my favorite, but diamond interchanges are a vast improvement over what is there in both locations now.

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Improvement or not, I see a lot of issues that should have taken precedence over this. The whole mall thing is on it's way out anyway.

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Originally Posted by EGrant

It's going to cause chaos during construction and spending $2 billion on highways isn't my favorite, but diamond interchanges are a vast improvement over what is there in both locations now.

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Keep in mind that this section of freeway needed to be rebuilt anyway. It's not like we're spending all the money just to add one lane in each direction. Adding lanes does add cost, but there would have been a significant cost even if we just rebuilt without adding lanes.

I do like that they're modernizing when possible. For example Square Lake Road interchange now has exit and entrances on the right side of the freeway instead of the left. These DDIs will further increase safety and reduce congestion. It also reduces the amount of land and pavement needed. At Big Beaver Road it even reduces the need for two bridges that were used as collector\distributors.

I've driven through the University Drive DDI, and I like them!

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Originally Posted by EGrant

It's going to cause chaos during construction and spending $2 billion on highways isn't my favorite, but diamond interchanges are a vast improvement over what is there in both locations now.

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Not to mention that this is one of the highest accident sites in Michigan.

The redo of the Square Lake/I-75 interchange leaves Gratiot/I-94 [[13 Mile) as one of the few left exits still around. I really don't want that one fixed... it flows so well the way it is. Not sure MDOT has plans to change it.

And then there is the I-94/US-10 [[Lodge Fwy) interchange with all the left exits. That will be interesting to see how they fix that in the "I-94 Lite" expansion of just going to 4 lanes without service drives.

Do self-driving cars really care about all these changes?:o

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Originally Posted by 401don

Do self-driving cars really care about all these changes?:o

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Ones that improve traffic flow, I'd say yes! But in theory the safety improvements won't matter in a world with self driving cars.

Accessing the highway for people in Sterling Heights and Warren
will become a summertime ordeal for many, many residents.
14 Mile is the borderline between the two Large cities.

Many accidents were caused by the """"Oh shit, is that the mall exit""""
cut across lanes to get off the highway - thoughtless, selfish drivers.

CrispyCreme might see an uptick in sales as drivers wait

Very good news indeed. The University Drive DDI is a world of difference over the old interchange. I had my doubts at first since I use that interchange a lot but I was won over quickly. This will only improve the 14 Mile and Big Beaver interchanges. Now how about improving the dreaded I-75/M-59 interchange?

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Originally Posted by yaktown

Now how about improving the dreaded I-75/M-59 interchange?

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This would be a very expensive undertaking. Everything today is at-grade. To modernize it, you'd have to build flyovers, bridges and ramps . A few years ago I looked at Google Maps, and it appears that there's enough land to do a modern interchange, but it likely boils down to funding. Hopefully if we get more funding allocated to transportation, this eventually makes the MDOT 5-year plan.

But yeah, I remember my dad bitc*ing about this in the 80's, and traffic was nothing back then compared to what it is today.

DDIs are fun. As much as I hate suburban sprawl, DDIs are good at easing traffic flow and for a minute I can pretend I'm in Britain. ;)

No doubt everyone will get lost trying to get to Field & Stream
750 W 14 Mile Rd, Troy, MI 48083


https://goo.gl/maps/3xRniGS6oUS2

Where are DDIs in service? I've never seen one. [[Albeit, most of my travels are by air, and then public transit into town.)

Update: A quick search online showed examples and videos. Most of them are not grade separated, it seems. Clearly grade separation is good, but its not strictly necessary.

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Originally Posted by Wesley Mouch

Where are DDIs in service? I've never seen one. [[Albeit, most of my travels are by air, and then public transit into town.)

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75 and University Dr. in Auburn Hills.

Thanks dt. Never knew that.

YAY Gov. Whitmer

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Originally Posted by Wesley Mouch

Where are DDIs in service?...

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M-59 at US-23 and I-96 at Wixom Rd. come to mind.

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Originally Posted by thomprod

M-59 at US-23 and I-96 at Wixom Rd. come to mind.

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Those are different and are not​ DDI's. Those are SPUIs - Single Point Urban Interchanges


DDI's are even better than SPUI's!

It will be SO much fun when they work on I-75
and 14 Mile Road --- at the exact same time !!!!!!!!!

https://www.macombgov.org/projects/1...re%20to%20Ryan

https://i.ytimg.com/vi/IKryyD3wvxE/maxresdefault.jpg

14 Mile is like the Moon, craters and all. FYI: stay in the inner lanes if you like your car...

Troy police said ramp and lane closures, as well as backed up traffic,
could be an issue when there are crashes on the freeway.
"That's the biggest nightmare for first responders,"
Lt.Josh Jones said. "How are we going to get our officers,
our medical personnel, tow trucks, all that equipment to the scene of the crash?"
Police said they are working with the Michigan Department of Transportation
to get gates put up on the closed ramps so first responders can access the freeway.

14 Mile & I-75 --- Bridge Demolition takes place this weekend.

https://www.clickondetroit.com/traff...s-this-weekend


Starting at 10 p.m. Friday, both directions of 14 Mile Road will be closed under I-75.

Posted detours use John R. Road, Stephenson Highway, Maple Road and Rochester Road