Phoenix Area Highways

[Sonic99]

Take a look at the fifth picture in the link below to see how I-10 would have split off west at the Durango Curve.  The photo shows one of the original overpasses that would have carried I-10 westbound traffic under the I-17 southbound to I-10 eastbound lanes:

https://www.azcentral.com/picture-gallery/travel/arizona/road-trips/2017/04/18/phoenix-area-freeway-history/100619786/

The aerial, dated 1963, shows the 17 where it made a significant turn at the Durango Curve.  The Broadway Curve, is on 10, and is sort of the opposite corner of the downtown freeway complex.  The aerials in the AZ Republic article clearly show the shortage of Freeways during the early growth decades of Phoenix.

I'm not sure what you are attempting to clarify here, as the Broadway curve wasn't mentioned in the post you quoted. The original intent was for the E-W portion of what is now I-17 was supposed to simply be I-10, with I-17 starting at the Durango curve and extending to the north. The original interchange built at what is now the "Split" by Sky Harbor originally had the through-lanes continue west, not turn north as they do now. The plan was for what is now the 51 to start there. When everything got shuffled around in the 70's and they moved the I-10 alignment to the current layout, they filled in the bridges at the Durango curve, and ultimately in the 80's tore down and reconfigured the Split to the configuration it has today.

[The Ghostbuster]

If the original Interstate 10 alignment in the Phoenix area had been constructed as proposed, would it have taken as long to construct as the realignment? After all, existing Interstate 10 in Phoenix wasn't completed until August 10, 1990.

[brad2971]

If the original Interstate 10 alignment in the Phoenix area had been constructed as proposed, would it have taken as long to construct as the realignment? After all, existing Interstate 10 in Phoenix wasn't completed until August 10, 1990.

The eventual alignment of I-10, and the controversy over "helicoil" interchanges, can be interpreted simply as the Arizona DOT and metro Phoenix taking its time to get I-10 right. End result is the 8-10 lane (not including auxiliary lanes) work of fine engineering you see today, with up to 16 lanes (6+2 HOV in each direction) through the Broadway curve starting next year.

They COULD have built it on the initial alignment, and very likely would have built it sooner. At the same time, the whole of I-10 from Buckeye to downtown Phoenix would have looked today like what we see on I-17 from the Durango Curve to I-10, and that would have been...inadequate to say the least.

[Sonic99]

Worth noting that during construction on the Broadway Curve project, some WB I-10 traffic is shifted over to the future "C/D" lanes from Broadway Rd over to just short of 40th St. They've got a "lane split" both directions so they can build the supports for the future SR143 flyovers in the center. Also quite a few of the sign gantries have gone up. Most still without signage, but you're starting to get an idea of what the finished product will look like next year.

[ztonyg]

Once the Broadway Curve project is complete, something needs to be done about the "mini stack" between I-10 / AZ 51 / Loop 202.

The "mini stack" seems to be the biggest choke point in that general area and is becoming a choke point during off peak hours.

The highest trafficked movement on the "mini stack" seems to be from W/B Loop 202 to W/B I-10 and the current 2 lane offramp configuration (with the lanes ending rather quickly requiring a merge once onto I-10) is absolutely inadequate for the traffic that flows through there.

[kernals12]

Once the Broadway Curve project is complete, something needs to be done about the "mini stack" between I-10 / AZ 51 / Loop 202.

The "mini stack" seems to be the biggest choke point in that general area and is becoming a choke point during off peak hours.

The highest trafficked movement on the "mini stack" seems to be from W/B Loop 202 to W/B I-10 and the current 2 lane offramp configuration (with the lanes ending rather quickly requiring a merge once onto I-10) is absolutely inadequate for the traffic that flows through there.

The Maricopa Association of Governments is way ahead of you.

[Sonic99]

Once the Broadway Curve project is complete, something needs to be done about the "mini stack" between I-10 / AZ 51 / Loop 202.

The "mini stack" seems to be the biggest choke point in that general area and is becoming a choke point during off peak hours.

The highest trafficked movement on the "mini stack" seems to be from W/B Loop 202 to W/B I-10 and the current 2 lane offramp configuration (with the lanes ending rather quickly requiring a merge once onto I-10) is absolutely inadequate for the traffic that flows through there.

The Maricopa Association of Governments is way ahead of you.

Saw that last week. I do wonder what the options would be. The lanes cutting down on WB-10 just past the 202 merge can't really easily be addressed without a widening of the Deck Park Tunnel. Which is, to put it mildly, not realistic.

[Plutonic Panda]

In Arizona, I'd say it's realistic. Most states couldn't even propose something like the South Mountain Freeway, an eight lane freeway for almost 30 miles with no tolls. ADOT built it in a couple years. I'd say they could widen the tunnel easier than they could widen I-17 in Phoenix.

[kernals12]

Once the Broadway Curve project is complete, something needs to be done about the "mini stack" between I-10 / AZ 51 / Loop 202.

The "mini stack" seems to be the biggest choke point in that general area and is becoming a choke point during off peak hours.

The highest trafficked movement on the "mini stack" seems to be from W/B Loop 202 to W/B I-10 and the current 2 lane offramp configuration (with the lanes ending rather quickly requiring a merge once onto I-10) is absolutely inadequate for the traffic that flows through there.

The Maricopa Association of Governments is way ahead of you.

Saw that last week. I do wonder what the options would be. The lanes cutting down on WB-10 just past the 202 merge can't really easily be addressed without a widening of the Deck Park Tunnel. Which is, to put it mildly, not realistic.

The answer is the Tres Rios freeway. Motorists who use that freeway will be encouraged to take the I-17 route past downtown rather than using the Deck Park Tunnel.

[Sonic99]

In Arizona, I'd say it's realistic. Most states couldn't even propose something like the South Mountain Freeway, an eight lane freeway for almost 30 miles with no tolls. ADOT built it in a couple years. I'd say they could widen the tunnel easier than they could widen I-17 in Phoenix.

Based on how the Deck Park Tunnel is constructed, there is no way to widen it in place. You would have to completely close it, demolish it, and build it wider. Getting the Tres Rios going ASAP with the connection to I-17 at the Durango Curve would be the better overall solution to relieve the traffic going through downtown and the tunnel.

[kernals12]

The deck park tunnel sees over a quarter of a million vehicles a day. I-17 at Central avenue sees just 117,000.

And, unlike the tunnel, I-17 has space for more lanes.

[ztonyg]

The deck park tunnel sees over a quarter of a million vehicles a day. I-17 at Central avenue sees just 117,000.

And, unlike the tunnel, I-17 has space for more lanes.

Why is mainline I-10 routed through the tunnel then as opposed to over I-17 until the "stack" interchange with a 90 degree westward turn at that location instead of the "mini-stack"?

[jgb191]

I don't know if the answer to my question has already been mentioned on this thread, but if so, feel free to provide the quote.

Is there a reason why Phoenix can't complete a continuous-circuit beltway or loop all around the city?  I'm seeing Highways 101, 202, and 303 on the map, but none of them enclose the circuit fully?  Are there any plans or propositions to complete any of the loops anytime in the foreseeable future?

[Bobby5280]

Is there a reason why Phoenix can't complete a continuous-circuit beltway or loop all around the city?

There are two big reasons: mountain ranges and tribal land.

The super-highway system in Phoenix is pretty decent, even if there isn't a neatly circular loop surrounding the metro. There are plans to build more super highways in the area.

[Max Rockatansky]

Is it really that hard to circle the metro areas with what is already there?  It certainly can be done mostly just stringing Loop 202 and Loop 101 together. 

[ztonyg]

I don't know if the answer to my question has already been mentioned on this thread, but if so, feel free to provide the quote.

Is there a reason why Phoenix can't complete a continuous-circuit beltway or loop all around the city?  I'm seeing Highways 101, 202, and 303 on the map, but none of them enclose the circuit fully?  Are there any plans or propositions to complete any of the loops anytime in the foreseeable future?

One of the proposals for the Loop 202 South Mountain Freeway was to have it connect to I-10 where the western terminus of Loop 101 is. That plan would've obliterated the downtown area of Tolleson so it was decided that it was a non-starter. The current loop system works fairly well without a full 360 loop.

[The Ghostbuster]

I think the mountains surrounding the Phoenix Metropolitain Area are what prevented a full 360-degree beltway from being constructed. If it were possible, I'd suggest extending Loop 303 eastward and then southward to have it connect it with Loop 101 around Exit 33 (N. 64th St.).

[Max Rockatansky]

I think the mountains surrounding the Phoenix Metropolitain Area are what prevented a full 360-degree beltway from being constructed. If it were possible, I'd suggest extending Loop 303 eastward and then southward to have it connect it with Loop 101 around Exit 33 (N. 64th St.).

A lot of wealthy home and land owners would shoot that idea down fast.  Carefree and Cave Creek have lots of people with money/political influence.

[kernals12]

If it wasn't for the Salt River Indian Reservation, ADOT long ago probably would've built a freeway connecting Loop 101 in Scottsdale to 202 in Mesa.

They did consider having the South Mountain Freeway directly connect to Loop 101, but concluded it wasn't worth the extra cost.

But despite all of that, I have yet to find a city of Phoenix's size that has fewer traffic problems, especially in the east valley.

[kernals12]

Here's a map of the freeway plan drafted by Wilbur Smith and Associates published in the Arizona Republic on February 28, 1960. The route of today's future Tres Rios Freeway was the originally planned route of I-10. Also, the Superstition Freeway would have extended through South Mountain Village before looping back to Loop 101.




In this edition from February 13, 1985, we can see they were considering an "East Loop": SR 143 would've been extended North to link up with the cancelled Paradise Freeway.

[kernals12]

The deck park tunnel sees over a quarter of a million vehicles a day. I-17 at Central avenue sees just 117,000.

And, unlike the tunnel, I-17 has space for more lanes.

Why is mainline I-10 routed through the tunnel then as opposed to over I-17 until the "stack" interchange with a 90 degree westward turn at that location instead of the "mini-stack"?

Because the tunnel provides easy access to midtown while I-17 runs past a bunch of non-descript warehouses and car dealerships.

[pderocco]

They could have made a loop out of 101 by renumbering the part of 202 west of Chandler to 101, and closing the gap by multiplexing 101 with I-10. Then, they could have multiplexed 202 with I-10 near downtown to make a loop out of that too. Then they'd have two intersecting loops. (Venn diagram?)

But why bother?

[Sonic99]

The deck park tunnel sees over a quarter of a million vehicles a day. I-17 at Central avenue sees just 117,000.

And, unlike the tunnel, I-17 has space for more lanes.

Why is mainline I-10 routed through the tunnel then as opposed to over I-17 until the "stack" interchange with a 90 degree westward turn at that location instead of the "mini-stack"?

In the early days of planning the Phoenix freeway system, I-10 was supposed to come in from the west at the Durango Curve, and overpasses were built into I-17 at that location to accommodate. That would have been the end of I-17 instead of the current configuration where there's that 4 mile east/west section. What runs along the current I-10 was supposed to be a different freeway. Ultimately it was decided to bring I-10 in from California along the current route instead, so the bridges at the Durango Curve were either removed or filled in and the I-10/I-17 split was reconfigured to what we see today. This picture from the abandoned Arizona Roads website shows it well.

[kernals12]

The deck park tunnel sees over a quarter of a million vehicles a day. I-17 at Central avenue sees just 117,000.

And, unlike the tunnel, I-17 has space for more lanes.

Why is mainline I-10 routed through the tunnel then as opposed to over I-17 until the "stack" interchange with a 90 degree westward turn at that location instead of the "mini-stack"?

In the early days of planning the Phoenix freeway system, I-10 was supposed to come in from the west at the Durango Curve, and overpasses were built into I-17 at that location to accommodate. That would have been the end of I-17 instead of the current configuration where there's that 4 mile east/west section. What runs along the current I-10 was supposed to be a different freeway. Ultimately it was decided to bring I-10 in from California along the current route instead, so the bridges at the Durango Curve were either removed or filled in and the I-10/I-17 split was reconfigured to what we see today. This picture from the abandoned Arizona Roads website shows it well.

How many other cities wound up building more freeways than were planned in the 1960s?

[Max Rockatansky]

The idea of having two freeways converging north of downtown Scottsdale is worth a laugh through modern lenses.  My house would have been in the ROW for the East Belt Expressway as it was right on the south bank of the Arizona Canal.