In the coming weeks, ADOT anticipates construction will begin on the ambitious Broadway Curve Improvement Project, the first major urban freeway reconstruction project in Maricopa County.  

The four-year project will bring improvements, additions and extra lanes to 11 miles on and around I-10, from the Loop 202 (Santan/South Mountain Freeway) to Interstate 17 near Phoenix Sky Harbor International Airport. 

If you’ve driven the route recently you may be wondering what’s with all the large drilling equipment and weekend activity if construction on the project hasn’t started yet?  

The work you’re seeing is pre-construction geotechnical work. Crews are boring and drilling to test the soil conditions deep below the surface, a necessary first step prior to any freeway construction project. 

Crews began this preliminary work in mid-April, assessing the condition of soil, rock and depth of groundwater along the Broadway Curve Improvement Project alignment. This type of testing is essential to test the conditions of the earth underneath planned or existing structures, such as bridges, walls and freeway lanes.  

The 40-foot-tall vehicles you’re seeing are truck-mounted Becker Hammer drill rigs, which bore deep into the soil and bring up a sample. The rigs can drill down as deep as 175 feet below the surface.  

For this project, these drills will generally sample from 80 to 125 feet deep if the boring is for bridge construction, and generally from 20 to 60 feet deep to test underneath future freeway walls. Once samples are collected they go to the lab, where the contents are tested and evaluated. 

In turn, the results of the tests and evaluations help determine how to design and build the highway and its many structures. 

“If the underlying soils are soft or loose, the foundation will need to be larger and deeper,” said Ramon Padilla, P.E., geotechnical project manager for Broadway Curve Constructors. “We are exploring what’s beneath the ground to evaluate the engineering properties of the subsurface (below ground) soil conditions, and design the foundations that will support the planned structures.” 

Padilla said this geotech work will last at least a few more months and could overlap with the start of construction.  

The Broadway Curve Improvement Project is on 11 miles of I-10 between the Loop 202 (Santan/South Mountain Freeway) and I-17 near Phoenix Sky Harbor International Airport. Additional work will occur on approximately 1 mile of east- and westbound US 60 (Superstition Freeway) between I-10 and Hardy Drive, and on approximately 1 mile of north- and southbound State Route 143 between I-10 and the southern end of the SR 143 bridge over the Salt River.

In October 1989, the Oakland Athletics swept the San Francisco Giants to win the World Series after the third game was delayed more than a week because of the Loma Prieta earthquake; Larry King got married for the sixth time; and Phoenix was only ten months away from officially connecting Interstate 10 from coast to coast.

Today’s Throwback Thursday photograph comes to us from deep inside the still-under-construction Deck Park Tunnel. The crews here are working hard to make sure all aspects of the structure’s integrity are being assembled just in time for its August 1990 debut.

And now, 31 years later, almost a quarter million motorists travel through downtown Phoenix’s favorite underpass on a daily basis.

Of course, as we revel in reminding our dear readers, the Deck Park Tunnel isn’t really a tunnel at all! In fact, it’s a series of 19 connected bridges. Of course, “traffic is flowing fine through the 19 connected bridges” rolls off the tongue just as nicely as “Can you can a can as a canner can can a can?” or “The horse raced past the barn fell.”

But Valley drivers are keen to take it one step further by just calling it “The Tunnel.” And we’re okay with that.

With thousands of followers on social media, we receive all kinds of questions. We try to answer everyone's questions or refer them to the person who can help. For the more frequently asked questions, we've started a new blog series called "Ask ADOT." Today's blog is the first in our series. 

A couple of weeks ago, one of our Twitter followers going by the handle @wsox05bears85 reached out to ask if we were planning to make repairs to a damaged portion of Interstate 10 in the West Valley.

As the messenger observed, some sections of asphalt are worn away between 43rd Avenue and Interstate 17. 

The answer is "yes." The Arizona Department of Transportation is aware of the damaged asphalt and plans to do "mill and fill" work on that stretch of freeway this summer. A "mill and fill"  project involves removing the existing layer of asphalt and replacing it with a fresh, new layer. The old asphalt is taken to a facility where it is recycled and used again. 

James Durlin, ADOT's Highway Operations Supervisor, said the work will occur over several weekends on more than just the stretch of highway between 43rd and I-17 (the stretch you see to your right is just west of 35th Avenue). The freeway between  Avondale Boulevard and 75th Avenue will also be resurfaced. 

As for the portion in between, from about 43rd to 75th, that asphalt was recently replaced as part of the work involving the new Loop 202 South Mountain Freeway. Watch for futher announcements about this work as it gets closer on az511.gov, our social media and our website. For more information, you can also call the ADOT Bilingual Project Information Line at 855.712.8530 or go to azdot.gov/contact and select Projects from the drop-down menu. 

This is part of a series of blogs called "Ask ADOT." If you have a burning question about transportation infrastructure, history, or you see something on our highways that piques your interest, send us a tweet or message us on Facebook and we'll try to find more information on it for you.

If you look at our AZ511 map as often as we do (and we hope you do!), you’ll notice a huge swath of green-marked land in the southwestern portion of our state. If you zoom in on that area just a little bit, you’ll notice the name: Kofa National Wildlife Refuge.

Running parallel to 43 miles of US Route 95 north of Yuma and 25 miles of Interstate 10 east of Quartzite, the refuge is home to a plethora of flora and fauna. Plants include native palm trees, a rare species of barberry that only grows in the region, and a great many cactus like prickly pear, cholla, pincushion, and some rather imposing saguaros. Animals include familiar desert dwellers like mountain lions, coyotes, foxes, jackrabbits, rattlesnakes, lizards, desert tortoises, Gambel’s quail, cactus wrens and several kinds of bats.

But there is one inhabitant that proved to be the impetus for the refuge’s creation.

Encompassing nearly 1,040 square miles and a more impressive-sounding 665,400 acres, Kofa National Wildlife refuge was established in 1939, originally as a sanctuary for the endangered desert bighorn sheep.

In fact, it was conservationist and British Army major (but born in Minnesota!) Frederick R. Burnham who first recognized the need to save the oversized ovis. He figured what better group to amplify his message than the Boy Scouts of America. Burnham contacted the Boy Scout's Theodore Roosevelt Council, located in Phoenix, and the scouts took the issue head on. In 1936, they embarked on a two year campaign holding radio interviews and school assemblies about the importance of protecting the sheep. They even mounted a “Save the Bighorn” poster contest, and Major Burnham furnished the winners’ prizes.

The scouts succeeded in their mission and The Kofa Bighorn Sheep Range, as it was known at the time, opened on April 2, 1939 as a joint venture of the U.S. Fish and Wildlife Service and the Bureau of Land Management. Fish and Wildlife gained complete control of the land in 1976 and rechristened it Kofa National Wildlife Refuge.

This effort so defined the early days of Arizona's Boy Scouts that the desert bighorn sheep became the group’s official mascot for some time.

The Kofa refuge, and the Kofa Mountain range located within, is named after the long-defunct King of Arizona Mine. The mine was established in the winter of 1896 and officially closed down in the summer of 1910, though ore was mined periodically up until 1937.

Within King of Arizona, miners found plenty of quartz embedded with gold.  Estimates at the time claimed that nearly $3.5 million worth of gold was excavated from the mine. Additionally, workers found wulfenite, a striking crystalized mineral with a beautiful orange glow, and two different strains of opal.

Property belonging to the mine was often stamped as “K of A,” thus leading to the portmanteau we use today.

We’ll leave you with one last fun fact: In the early 1940s, General George Patton trained soldiers on the refuge’s rugged terrain. Known as the Laguna Maneuver Area, armored divisions and infantry battalions went through countless exercises and had extensive weapons training using projectiles, mines, and bombs before they were deployed to the deserts of North Africa during World War II. To this day, military munitions can be found throughout the Kofa Wildlife Refuge. Hikers are encouraged to follow the Three Rs: Recognize, Retreat, Report.

You must be at least a little curious by now. So take a day off! Get out of the house and explore over half a million acres of Arizona wilderness, here thanks to due diligence of Arizona's Boy Scouts over 80 years ago. The refuge can be accessed off of Interstate 10 and Vicksburg Road. You can visit az511.gov or download the AZ 511 app for directions. 

We all know what to expect when the monsoon whips up dust storms that race across the desert between Tucson and Phoenix: strong winds, limited visibility and hazardous driving conditions.

But drivers on that stretch of Interstate 10 should expect something very different this summer when storms hit: reduced speed limits, speed feedback signs and new overhead boards that display urgent safety messages.

These features are now working together as part of ADOT’s dust detection and warning system, which became operational just in time for the 2020 monsoon season that officially began June 15. This video shows you how this first-of-its-kind system works on a 10-mile segment of I-10 between Eloy and Picacho Peak, along with what drivers will see when dust storms automatically activate the system.

This system was developed by ADOT to improve safety during dust storms. But it only works if drivers heed the warnings. So make sure to pay extra attention to the safety messages on overhead signs and to obey the reduced speed limits, which are enforceable. Speed limits can drop to as low as 35 miles per hour, depending on real-time conditions in the area.

You can read more about the dust detection and warning system on our website.

Please remember that this technology is no substitute for common sense. Wherever you are traveling, be sure you've reviewed our dust storm safety tips at PullAsideStayAlive.org. 

We’re building a safer and more efficient interchange at Interstate 10 and Ruthrauff Road, but that can’t happen until we demolish all the old stuff.

To show you what’s involved, we’re sharing this ADOT video of the recent work to dismantle the eastbound I-10 bridge over Ruthrauff Road/El Camino del Cerro. Watch as Dan Casmer, ADOT’s senior resident engineer on the project, explains why we’re lowering I-10 so a new bridge can carry Ruthrauff Road over the highway and the Union Pacific Railroad tracks.

The video also shows how crews are doing what seems like a ton of work, so to speak. But if you’re counting how much material crews are removing, they’re really doing 1,215 tons of work.

Here’s a quick look at much concrete and steel crews ripped apart while demolishing the bridge:

• 1,090 tons of concrete
• 85 tons of steel girders
• 40 tons of steel rebar

One thing you won’t see in the video or if you drive through the area: Everything being trucked away.

Only the steel will leave the site, hauled off to be recycled. Most of the concrete will remain within the mile-long project area. It will be crushed and used as fill material.

The $129 million I-10/Ruthrauff Road project began in January and is scheduled for completion in late 2021.

With state highways essential to delivering goods and services, ADOT, its employees and its contractor partners are dedicated to delivering transportation improvement projects during the current public health situation. To learn more please visit azdot.gov/covid-19-resource-center.  

Since an eastbound Interstate 10 bridge started carrying traffic over Ruthrauff Road in 1965, the number of vehicles that have traveled this northwestern Tucson locale is impossible to calculate.

But once crews began demolishing the structure this week, we can count exactly how much time it took to reduce the bridge’s surface into concrete rubble and twisted rebar: two days.

This Flickr album of the demolition work shows the rapid progress we’re making to rebuild I-10/Ruthrauff Road interchange only two months after starting the $129 million project.

As for the remaining parts of the bridge, they’ll also be history by the end of the week.

If you’re wondering how I-10 traffic can keep flowing with one of two bridges now gone at Ruthrauff Road, here’s the solution ADOT’s project team has in place: Westbound I-10 traffic is now getting through the work zone on the westbound frontage road, while eastbound I-10 traffic has been shifted to the old westbound lanes.

Some temporary sections of pavement allow three lanes of traffic to flow in each direction. And we’re maintaining access to all businesses with other temporary changes to the frontage roads.

The demolition work is just one of many dramatic changes drivers will see until the I-10/Ruthrauff Road project is completed in late 2021. Stay tuned for more photos and other updates.