Salt Lake Transit News Thread - Page 164

Sight-Seer · #**3261** Posted **Jul 22, 2011, 1:38 PM**

Another interesting development is the DDI (diverging diamond interchange) at 21st South and Bangerter. These are rare, but might become more common. This would be the third one in Utah that I know of. The rebuilt I-15 in Utah county has two: American Fork Main Street and American Fork 5th East.

wrendog · #**3262** Posted **Jul 22, 2011, 3:32 PM**

Quote:

Originally Posted by Sight-Seer

Another interesting development is the DDI (diverging diamond interchange) at 21st South and Bangerter. These are rare, but might become more common. This would be the third one in Utah that I know of. The rebuilt I-15 in Utah county has two: American Fork Main Street and American Fork 5th East.

I use the AF DDI every day. It's really effective. I like it.

s.p.hansen · #**3263** Posted **Jul 23, 2011, 12:15 AM**

Great Viaduct update SLCdude!

It's becoming more and more real. I can't wait!

CountyLemonade · #**3264** Posted **Jul 25, 2011, 4:57 AM**

Quote:

Originally Posted by Sight-Seer

Another interesting development is the DDI (diverging diamond interchange) at 21st South and Bangerter. These are rare, but might become more common. This would be the third one in Utah that I know of. The rebuilt I-15 in Utah county has two: American Fork Main Street and American Fork 5th East.

And the thing about this DDI is that it's using the existing bridge over SR-201, which is a first for Utah. It'll be interesting to see how UDOT ends up adapting the old bridge, which hails back to 1986.

gemery · #**3265** Posted **Jul 25, 2011, 10:36 PM**

What is a DDI, exactly. I looked it up, but I still don't get it.

arkhitektor · #**3266** Posted **Jul 25, 2011, 11:04 PM**

Quote:

Originally Posted by gemery

What is a DDI, exactly. I looked it up, but I still don't get it.

wrendog · #**3267** Posted **Jul 26, 2011, 1:03 AM**

Quote:

Originally Posted by gemery

What is a DDI, exactly. I looked it up, but I still don't get it.

Watch it in action here:

http://www.youtube.com/watch?v=xWHEi8baCPE

SL Dekster · #**3268** Posted **Jul 26, 2011, 4:26 AM**

Quote:

Originally Posted by Sight-Seer

Another interesting development is the DDI (diverging diamond interchange) at 21st South and Bangerter. These are rare, but might become more common. This would be the third one in Utah that I know of. The rebuilt I-15 in Utah county has two: American Fork Main Street and American Fork 5th East.

A fourth DDI is currently under construction at the SR-92/I-15 interchange, expected to be complete this fall. A really dumbed down simulation video explaining a DDI and all of the improvements along SR-92 (Timpanogos Hwy) is available at:

http://www.udot.utah.gov/sr92/

SL Dekster · #**3269** Posted **Jul 26, 2011, 4:34 AM**

Has anyone heard about the upgrade to a Thru-Turn Intersection (TTI) that is supposed to be happening soon at 12300 S & Minuteman Drive?

http://www.udot.utah.gov/thruturn/

This is the first I've ever heard of this type of intersection. It seems like a complete pain in the neck, but if the cited statistics are correct, that only 20% of the intersection volume is left turns, then it makes complete sense.

Also, props on the impressive simulation-- its easily the best quality UDOT video I've ever seen.

CountyLemonade · #**3270** Posted **Jul 26, 2011, 5:56 AM**

Supposedly, that "Thru Turn" (or Michigan left to the rest of the country) has worked in other parts of the country. We'll see; most people have poo pooed the concept, but I'm giving it a chance. I'm not sure what was wrong with the set-up before 2003, when there was a direct connection between I-15 and State Street. Ah well.

As for UDOT animations, look at this one. Pretty good, eh?

• Video Link

But anyway, once I-15 through Utah County's finished, it'll rival the current state of I-15 through Salt Lake. Hurrah for public infrastructure investment!

StevenF · #**3271** Posted **Jul 26, 2011, 6:02 AM**

link doesn't work.

i-215 · #**3272** Posted **Jul 26, 2011, 6:09 AM**

I absolutely LOVE DDI. And I was a huge skeptic when I first learned of it.

http://www.udot.utah.gov/sr92/interchanges.php

• Video Link

gemery · #**3273** Posted **Jul 26, 2011, 1:52 PM**

Interesting design. It seems to flow smoothly, but that might be because it's a simulation. Liked it, though. From the video that wrendog posted (also, you can see this in the others, but his was the best for the following), there was some great landscaping. I hope that landscaping really ends up there. As far as efficiency goes, I'll have to try it to see how it feels.

SL Dekster · #**3274** Posted **Jul 26, 2011, 6:04 PM**

Gemery the main thing to remember with a DDI is that the two signal controlled intersections alternate with each other. If one is green, the other is red. They also have very short queue times-- like 30 seconds.

So if you're entering on the secondary road and making a left onto the freeway you have roughly a 50% chance of hitting 1 very short red.

Worst case scenario, which is statistically far less common, is that you're going straight through from secondary to secondary. You'll pass through both intersections, but only one of them will be red. Which means you have a 100% chance of hitting 1 very short red.

John Martin · #**3275** Posted **Jul 26, 2011, 11:50 PM**

So the new TRAX lines are opening on August 7th, but you can ride on August 3rd if you bring a can of food to donate.

http://www.rideuta.com/mc/?page=UTA-...RAX-augustTRAX

Not sure which stations are hosting festivities. I guess there will be more details soon.

wrendog · #**3276** Posted **Jul 27, 2011, 12:02 AM**

Quote:

Originally Posted by gemery

Interesting design. It seems to flow smoothly, but that might be because it's a simulation. Liked it, though. From the video that wrendog posted (also, you can see this in the others, but his was the best for the following), there was some great landscaping. I hope that landscaping really ends up there. As far as efficiency goes, I'll have to try it to see how it feels.

I was really skeptical when I first saw that video run through. Now that I have used the thing hundreds of times, it is awesome. It flows so very well and very minimal wait time at lights. I love it.

John Martin · #**3277** Posted **Jul 27, 2011, 3:20 AM**

Quote:

Originally Posted by John Martin

So the new TRAX lines are opening on August 7th, but you can ride on August 3rd if you bring a can of food to donate.

http://www.rideuta.com/mc/?page=UTA-...RAX-augustTRAX

Not sure which stations are hosting festivities. I guess there will be more details soon.

"River Trail, 1070 W. 2320 South; Redwood Junction, 2770 S. Redwood Road; Decker Lake, 3100 S. Decker Lake Drive; and West Valley Central Station, 2750 W. 3590 South. Trains run every 15 minutes beginning at 9 a.m."

http://www.sltrib.com/sltrib/news/52...south.html.csp

shakman · #**3278** Posted **Jul 27, 2011, 4:18 PM**

I wonder if DDI would work in the DC area... Seems like nothing does...

Any - hows... Southwest will be making a route change... SLC - BOI service will be been cancelled starting January 7, 2012. At the moment, there are no plans to re-instate this service in the future.
http://airlineroute.net/2011/07/26/wn-jan12/

RC14 · #**3279** Posted **Jul 27, 2011, 8:54 PM**

Do we have any idea when we could expect construction to start on the sugarhouse street car line phase 1?

SLCdude · #**3280** Posted **Jul 28, 2011, 7:11 AM**

Quote:

Originally Posted by RC14

Do we have any idea when we could expect construction to start on the sugarhouse street car line phase 1?

I've been wondering about that myself. I'll try to make the public meeting tomorrow for some insight