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.

Today’s Throwback Thursday entry goes back to 1971. Flip Wilson is on your TV, the price of peanut butter is 59 cents, and Sunset Point is looking mighty inviting.

Yes, here’s a look at Interstate 17’s favorite rest area one half century ago. We can spot a Volkswagen Bus, a pickup with a pretty impressive camper shell, and perhaps a Buick Skylark towing one of those fancy silver Airstream trailers.

Fifty years later, Sunset Point remains a popular pit stop for folks traveling up and down I-17. Except now there are a few more vending machines and a lot more parking. Those baby trees in the foreground are undoubtedly nearly grown now, too.

Not much beats the breathtaking views Sunset Point offers. Especially around dusk, when you can take in a little thing called…the sunset.

The highway will definitely look different in the next few years. Interstate 17 is about to embark on an ambitious widening project beginning in 2022, bringing one additional lane in each direction and two flex lanes to the stretch between Anthem and Sunset Point by late 2025.

Today’s Throwback Thursday photo comes to us from the era of shag carpeting and Led Zeppelin.

In the early 1970s, ADOT crews were blasting their way through the Virgin River Gorge to complete Interstate 15 in the northwestern corner of our state.

The photo in question implores those standing by to turn off their 2-way radios. And if you look closely in the background, you’ll see why.

That plume of smoke you notice wafting in the air is from one of many blasts made to the earth in order to properly build the highway.

Signals from 2-way radios can interfere with the signals from blasting devices, causing some unwanted mishaps. For the same reason, a sign like that today would also instruct nearby folk to turn off their cell phones.

Arizona’s portion of Interstate 15 was officially completed in 1973, and now ADOT is continuing work to improve the bridges that travel over the Virgin River.

Though CB radio is, alas, not as popular now as it was during the disco era, following all posted signs while going through a construction zone is still a big 10-4.

It seems like we can't get enough of talking about old US Route 66. Though it has been a defunct designation in Arizona for 35 years now, the legacy of the great Mother Road continues to inspire and inform us today.

Perhaps that can be seen nowhere clearer than in the towns left along its route. Which brings us to this photo. As you might be able to see, this is an undated photo of Ash Fork, which today sits at the junction of State Route 89 and Interstate 40. There's no date on it, but we figure that there are enough context clues – unpaved roads, vintage vehicles, buildings, old time gas pumps – to give someone enough information to track down a rough year. If that person is you, please give us your best guess! The only thing we can say for sure is that it was in a collection of photos that predate 1950. 

But, this was a good opportunity to look into the history of Ash Fork and where it came from. It's origins are actually tied to transportation, but predate the Main Street of America by decades. It's also been very fortunate to always sit at important junctions.

In his "Roadside History of Arizona" state historian Marshall Trimble says the town was founded in 1882, when Cooper Thomas Lewis built a small grocery store next to the local railroad tracks. Skip forward a few years and the community was also graced with a post office and Wells Fargo station. In 1893 the townsite moved to the southside of the rail line because all the buildings at the original townsite on the north side were destroyed by a fire.

The early 1890s also had plenty of good in store, as a rail line connected it with Prescott and eventually Phoenix. The aptly named Santa Fe, Prescott and Phoenix line may have been longer that the competing route going through Black Canyon, but as our Arizona Transportation History says, it was actually quicker and more comfortable. This established rail route, which also went through Wickenburg, may have also been a factor when the original Phoenix-to-Prescott road was built in the early 20th century.

Trimble also says that the connecting of Phoenix and Prescott via the railroad is where many historians date the closing of Arizona's frontier period.

In the 1920s, with arrival of the automobile age and the start of the famous US 66, Ash Fork became one of many towns served by the motorists now traveling between Los Angeles and Chicago. Ash Fork even boasted the Hotel Escalante, of the famouse pit stops/restaurants/hotels run by tourism magnate Fred Harvey.

The community was hit by a series of setbacks, such as the railroad line moving 10 miles to the north in the 1950s, and Interstate 40 deciding to bypass it in the 1970s. 

Though the highway doesn't run through town any more, Ash Fork still sits were State Route 89 meets I-40, meaning there is still a need for gas, snacks and a place to stop. As this photo and modern Ash Fork could tell you, location really is everything.

As you might have noticed by now, we do love our historical transportation photos. 

It's not really for their aesthetic value – though it's hard to mess up a shot of the inherently beautiful of Arizona's landscape - but rather what interesting tidbits we can glean from them.

Take today's example as two clearly older vehicles make their way down a twisty rural route that is marked as "U.S. Highway 66, Oatman to Kingman, Arizona."

The thing that caught our attention (and which might have caught yours as well) is that the road between those two communities today is not a US nor a state route. Instead, the Oatman Highway is a county road. But the photo clearly identifies this as part of the famous "Mother Road," US 66. So... what happened? 

To root out this puzzle we turned, like we so often do, to our exhaustive history of transportation in Arizona. Here we learn many of the basics of US 66's story: How the Arizona portion developed out of the National Old Trails Highway in the 1910s and the Santa Fe Highway in the 1920s, how many followed it west in the 1930s in the mold of "Grapes of Wrath," and how following World War II it became a main route to carry vacationers and job-seekers alike between Chicago and Los Angeles, and how it was finally decommissioned in Arizona in 1985. 

Finally, after much digging, we found what we were looking for. In the early 1950s an improvement project rebuilt 170 miles of US 66 in the state to help undo the damage from the hordes of vehicles that now used it. As part of these improvements, US 66 was routed away from Oatman in 1952. The new alignment was meant to eliminate a twisty, hazardous section of highway and replace it with something safer. It would turn out to be one of the earliest of many realignments away from communities in coming years as the interstate system came into being.

That's just one bit of highway history that we could glean from this photo. As you might have noticed from our Throwback Thursday series, there's a lot more to be found in our archives. If you are also interested in learning more about Arizona's roads, feel free to take a deep dive through our albums of historical photos on Flickr! 

Over the years, we have delved into our archives to bring you photographs from a lot of times and and places. From grading a road with mules to the Highway Hawk's appearances at events to a bewitching shot of the "Devil's Highway," we've shared a lot about how things used to be. 

However, all the photos we have shown you up to this point have had something in common. Whether we were talking about child safety seat standards (or lack thereof!) in the 1970s, a hard-working pickup truck from the Grand Canyon Airport in the 1950s, or a town hall meeting in Globe nearly 50 years ago, we had some information to go off of. Sometimes they are maddening vague (such as this photo, where we only learned her name by accident), but we still had something to go off of.

But not today. 

That's because, as we went through our archives looking for something good to pull, we stumbled across this shot of some lonesome highway work that is simply titled "Unknown 2" (to distinguish it, of course, from another, unrelated photo in the same collection named "Unknown 1"). 

And now you have all the information that we do. Or at least as much information as the communications team has without going to everyone of a certain age at ADOT to see if they know where or when this might have been taken. 

It's obviously depicting some sort of roadwork on a downhill slope and it's in a collection that's all from 1970 or later, but beyond that we can't hazard a guess. So we decided to pass it along to you all to see if any of our readers out there wanted to try their luck.

Ultimately it doesn't matter where this is or when the photo was taken. We build roads to get people where they need to go without having to worry about how they got there. That means this highway could stand in for just about any state highway – silently serving Arizona drivers without any fanfare.

However, that being said, we would love to be able to solve this puzzle. So if you have any ideas about where/when this was, we would love to hear them! Reach out to use on Twitter, Facebook or Instagram to let us know your thoughts!

We have quite the talented group of shutterbugs here at ADOT, as evidenced by the quantity and quality of the highway construction photos you can easily find on our Flickr page.

If you have paid any attention to our Throwback Thursday blogs, you know that we also have a rich archive to draw on to see what construction was happening decades ago. Between both, there are thousands of photos that are each capturing a moment in time, showing us the people, places and equipment that came together to build the transportation infrastructure we enjoy today.

That's why we like this photo so much. As the caption says, this was taken during paving operations on February 26, 1934 on an unnamed stretch of Thomas Road. You can immediately spot the plethora of differences that has taken place in the last nearly 90 years. There's the equipment, the old cars in the background and the wooden telephone poles running the length of the street. Can you imagine visiting a construction site in a three-piece suit and fedora?

Also, how about that street? In 2020, Thomas Road is a major route that runs – with some gaps – between 144th Avenue in Goodyear to Power Road in east Mesa, cutting through much of the heart of the Phoenix metro area. It's come a long way from the dirt-packed, house-lined path that we see here.

This photo is interesting to us because today ADOT oversees state highways and freeways. But apparently, at this time, the then-named State Highway Department was interested in the paving happening along this city street. 

There's a lot to unpack in this photo, but it does raise an interesting question: What will future ADOT bloggers say about the photos we're taking now for the construction on I-10 at Ruthrauff or I-17 and Happy Valley? 

At first glance this photo might seem a little ordinary. A couple vehicles driving down a road next to some powerlines and buildings.

For those who enjoy visiting Lake Powell or, like us, are road buffs, you'll recognize this as the US 89 bridge that crosses the Colorado River just south of the Glen Canyon Dam near Page. Though, truth be told, that doesn't make this photo seem less pedestrian (pun intended).

But when we found this undated photo in our archive, we started thinking about that bridge and the US highway that runs over it. What could this ordinary scene tell us about Arizona's transportation history?

As we've told you about before, US 89 is actually the first designated north-south highway in the state and was part of the first batch of highways to actually be given a number in the mid-1920s. Our 2012 Transportation History report has a whole section just on this one highway, which adds that at one point US 89 stretched between Canada and Mexico, and was planned to be part of a projected intercontinental road that would have ended in Buenos Aires.

For the first few decades of its existence, US 89 actually stretched between Nogales in the south and Fredonia in the north, connecting Tucson, Florence, Mesa, Phoenix, Wickenburg, Prescott, Ash Fork and Flagstaff. As part of its traversing of the state, it crossed two important bridges, at Cameron over the Little Colorado River and then Marble Canyon over the Colorado River.

With the completion of the Glen Canyon Dam in 1963 and the bridge in this photo the following year, US 89's route was changed to swing through Page and then down to Flagstaff, making the Fredonia to Bitter Springs section the alternative, or US 89A. And, like most of the early highways, US 89 was heavily impacted by the interstates, which took away much of its raison d'être as a major north-south connector. By 1992, all but the northermost stretch had been decomissioned as a US highway. 

Once you consider all that, we guess it makes this photo look a lot less ordinary. What additional fascinating bits of highway history might be sitting under other well-traveled routes?

Going uphill is a fact of driving some Arizona highways, especially as you go from the Sonoran desert in the south up to the mountains or onto the Colorado Plateau. From the earliest days of transportation, that has always been the case. 

Which brings us to this excellent photo from 1932 we found in our archives. As the caption tells us, this shot of rocks beside – and on – the road is Yarnell Hill along the Phoenix-to-Prescott Highway. 

Anyone who has driven from Congress to Yarnell, or vice versa, is familiar with this particular portion of what is now State Route 89. If you take it today, you ascend roughly 1,000 feet in a little under 4 miles. And that's the modern road with today's vehicles. Imagine doing it on a graded dirt road in the car you see in the background. We also don't envy the crews that had to remove those hefty boulders from the road without the benefits of a frontloader. 

And how about that Phoenix-to-Prescott Highway? We told you about this highway in another blog post, where it was one of the original north-south roads envisioned by Arizona's territorial government in 1909. That route originally was planned to run directly south from Prescott to Phoenix, which includes some notoriously steep terrain. By 1917, the route between Prescott and Wickenburg, and then on to Phoenix, became the better option. That's the route US 89 would take in the 1920s as it climbed from Nogales to the Utah state line, and it's still the way State Route 89 will get you to Prescott. 

Times may have changed, but rock removal along state highways remains a concern for ADOT. In March 2020, crews were busy clearing boulders from along State Route 89A near Jerome and – you guessed it – on State Route 89 near Yarnell. 

We didn't have to search too far back to find this interesting shot of a bridge in the process of being built.

Drivers who travel between the Phoenix area and Payson may have no difficulty recognizing this as the State Route 87, known as the Beeline Highway. The photo comes from 1998 in the middle of a project to upgrade SR 87 to four-lane divided highway. The bridge that would eventually support the highway is being built using segemented construction. Basically, the bridge is built bit by bit with cast-in-place concrete segments that are added on using a specialized casting machine. That's the big white rigging you see there.

You'll notice, however, that there is a second machine in background on the other side of the bridge being built. The same work is happening on that end in what is known as cantilevering. Basically, segements are being added out from the supporting pier on both sides either simultaneously or in alternating turns to keep the entire structure in balance. Eventually all segements are connected and you have one, long bridge to drive across. In this case, the photo appears to be of the Screwtail Bridge, just south of Sunflower, which wound up being an impressive 1,080 feet, spanning a 105-foot-deep canyon. 

This innovative method was needed because the terrain between Phoenix and Payson is pretty rugged, as reflected in some of the curves and grades of the road's original alignment. By building bridges this way, ADOT was able to straighten and flatten the roadway a bit while also widening it and making sure to steer clear of sensitive riparian areas and wildlife corridors.