When it comes to driving through the Interstate 10 Deck Park Tunnel north of downtown Phoenix, it’s important that you’re not left in the dark.

It has taken a few visits to the idea factory to explore possible ADOT projects to upgrade, and actually replace, the original lighting system dating back to when the famous tunnel opened in 1990 as part of the “Final Mile” of I-10 constructed across the entire U.S.

Fortunately, the waiting has paid off with an innovative project being installed by ADOT crews that has now reached a milestone with work to add new LED lighting in the westbound side of the tunnel finished.

That means more than 1,500 of the LED lights are now lighting the way for westbound I-10 drivers using the tunnel. ADOT crews are slated to complete the eastbound installation this summer as more light fixtures are provided by a manufacturer.

While previous project ideas were considered more expensive, ADOT found a company that could provide LED lighting fixtures that work in the same locations as the original high pressure sodium lights. The result is a $1.4 million safety enhancement project that includes the “in-house” installation work by an ADOT team.

An initial review of the new westbound lighting is already showing a more than 60 percent reduction in energy consumption. We’re estimating annual energy savings of more than $175,000, which by my limited math skills would mean the project will pay for itself in less than 10 years.

The new LED lights in the Deck Park Tunnel are providing a noticeably improved, brighter and whiter level of light compared to the yellow tone of the old, outdated high pressure sodium lights. The new bulbs certainly will last longer, no doubt having a positive effect on maintenance work and costs. 

As with the old lighting system, the improved LED tunnel lights will be set at appropriate transitioning levels during daylight and nighttime hours to allow a driver’s vision to adapt given outside lighting levels. For example, the system will run fewer lights at night because of lower nighttime light levels outside the tunnel.

So ADOT has reached the halfway point with the I-10 tunnel lighting upgrades. We’ll keep you posted on when the next installation work on the eastbound side will require an overnight closure so crews can do even more work. As always, please focus on safe driving, especially as we head into the summer travel season.  

As transportation departments and other safety organizations across the country wrap up this year’s National Work Zone Awareness Week (NWZAW), we truly hope that the emphasis on this life-and-death issue stays with you at all times when you’re behind the wheel.

The national event, held April 26-30, provided ADOT with an opportunity to place a spotlight on dangers associated with traffic traveling through work zones – not just on our state highways but also local streets in communities across Arizona.

We want to thank media outlets who provided coverage of NWZAW, including live reports from an I-17 work zone where the freeway bridge over Central Avenue in Phoenix is being reconstructed. It was great to see TV traffic reporters here in the Valley taking part in “Wear Orange Day” on Wednesday as part of the week’s events.

Nearly a thousand fatalities occurred in 2019 in work zone-related crashes across the U.S., according to statistics provided by the Federal Highway Administration. The majority of those deaths involved drivers or passengers in vehicles.

Here in Arizona, law enforcement crash reports showed there were 15 work zone-related fatalities across the state in 2019. That number was 17 deaths in 2018. Last year ADOT lost one of its own, Frank Dorizio, who was struck and killed by a vehicle while he was setting up a sign along Interstate 10 in the Casa Grande area. 

These are the top reasons we ask you to take this issue to heart. You indeed could be a life saver by slowing down and staying alert when approaching any work zone.

If you were out on one of our Arizona freeways or highways during National Work Zone Awareness Week, you may have seen one of our safety messages, including “Give ‘Em A Brake, Stay Alert in Work Zones.” 

We’re looking out for the men and women who work dangerous jobs in order to make things better as we move about the Grand Canyon State. But we’re also looking out for you, and any passengers traveling with you. In turn, we depend on you to remember the importance of being careful well beyond this one week. 

Does merging on the highway pose a dilemma for you?

For a lot of us, a “Merge Left (or Right)” sign triggers an inner debate: Should we politely do what the sign says and merge now, or should we wait to merge later – and gain more ground – but feel guilty for cutting?

The zipper merge system ends the debate and encourages drivers to wait until the last minute to merge – without guilt!

What is the zipper merge, you ask, and what does it have to do with ADOT?

Glad you asked! No, it’s not a new line dance or a carnival ride, but a traffic system that organizes how motorists merge when a lane closes.

ADOT has been using the zipper merge on various projects since 2016. Currently, it is being used on the Meteor Crater and Two Guns bridge deck replacement and rehabilitation project on Interstate 40 east of Flagstaff.

Okay, but how does it work?

Here’s how, according to AAA. The zipper merge is like a zipper on a pair of jeans. Just as the teeth of your jean’s zipper come together, the zipper merge keep traffic coming together, smoothly closing the lane.

Motorists stay in their respective lanes until the final merge point, which is efficient because it’s not leaving one lane empty. It uses all available lane space.

At the merge point, vehicles take turns merging: The car in one lane merges, and then a car in the other lane merges, then the car in the next lane merges, and so on. Like a zipper!

Additionally, ADOT is testing a “smart work zone” in the westbound direction of the I-40 project. It uses a dynamic merge system with electronic signs and sensors and can be controlled remotely. When traffic is light, the signs ask motorists to merge well ahead of the closure. When traffic is heavier, the zipper merge system kicks in and signs ask drivers to merge later. You can read more about it here.

Dilemma resolved!

For more information about the zipper merge, check out this classic ADOT blog.

To see photos of the I-40 bridge deck and rehabilitation project, visit the ADOT Flickr album.

It’s definitely a case of “out with the old and in with the new” when it comes to the lighting system inside the Interstate 10 Deck Park Tunnel north of downtown Phoenix.

The Arizona Department of Transportation has been pursuing a project to replace the original tunnel lighting system for several years now. After all, the Deck Park Tunnel opened to traffic in August 1990 and the old style high-pressure sodium lighting system has been in use for all the 30-plus years since. An upgrade has been much needed.

Following consideration of various project ideas over time, enough funding was identified for a $1.4 million project that is now underway. New LED lighting fixtures are being installed, over the course of the next few months, to replace the old fixtures that held the sodium lights.

A test installation was done with a small section of lights last year and more of the new lights were put in during January above the westbound I-10 right lane within the tunnel. In fact, you might have noticed the “whiter” LED lights that are in versus the “yellow/amber” glow of the old lights.

The project team anticipates needing several Friday night closures of I-10, in either direction, over the next few months in order to change out the more than 3,200 fixtures that help light the way when you’re traveling through the tunnel.

The new LED lights are energy efficient and can be expected to last well over twice as long as their sodium predecessors. The anticipated annual energy savings are more than $175,000. Those savings will over time help pay for the cost of installing the new system.

So be prepared for ADOT to let you know which Friday nights will be used for closures so the lighting improvement work can advance this spring. Our Weekend Travel Advisory is a good thing to subscribe to via azdot.gov/Subscribe.

At age 30, the Deck Park Tunnel is getting a new look and you’ll notice a difference. As some experienced models might tell you – it’s all about the lighting.  

Arizona’s mountainous terrain is as beautiful to look at as it is to drive through, but keeping dirt from those slopes off roadways can pose a technical challenge.  

That’s one reason the Arizona Department of Transportation has deployed highly sophisticated measuring equipment on embankments across the state.

On a recent trip to State Route 87 between mileposts 224 and 225 south of Payson, ADOT Geologist James Lemmon and Engineer-in-Training Ivan Bystov inspected two examples of this technology. The hill they're working on is part of a decade-old landslide known as the Sunflower Landslide.  

Lemmon and Bystov hiked along a ridge on the east side of the highway toward what looked like a yellow chimney sticking out of the hillside. In fact, the yellow riser is a steel casing to protect the inclinometer pipe and the piezometer equipment inside the well.  

The inclinometer enables scientists like Lemmon and Bystrov to measure the rate of slope movement over time.

“We are trying to see if there is a change or any instability,” said Lemmon, an ADOT Geotechnical Design Section-Bridge Group member.

The information is used to take preventive action if the hill is moving down a slope toward the roadway.  

“We know we must do something to buttress it to keep it from moving,” Lemmon said.

Lemmon said there are about 130 individual inclinometer wells installed at 30 embankment sites around the state. Sunflower Landslide has over 20 active inclinometers that are read on a regular basis. Some are on the roadway surface, many are on the near slopes and several are near the very top of the steep road cutouts and mountain slopes.

The piezometer measures moisture and saturation levels.

"When designing and constructing bridge foundations, we need to know the depth of where the saturated water level is under the surface so construction equipment doesn't sink and disappear into the saturated earth, Lemmon said. "And we design the foundation for a saturated groundwater situation. Those depths to water are measured by the piezometers."

The piezometer Lemmon and Bystrov displayed goes down about 60 feet deep, but Lemmon said there locations on the Sunflower Landslide where they go down nearly 400 feet deep.

Motorists traveling to Payson from the Valley along State Route 87 may be familiar with the road and scenery, but are probably unaware of the feats of science and engineering designed to keep them safe as they pass along the way.

“On State Route 87 we rebuilt things so we don’t have steep grades and windy roads and much of it is safer,” said ADOT Geologist James Lemmon. “We don’t want streams flooding and rocks falling onto the road.”

One such project is the soil cement and hydro-seeded mulch mixture that covers grouted riprap along the banks of Slate Creek on SR 87 northbound, at milepost 227. This is about 7 miles before SR 87 intersects with State Route 188. 

The hydro-seeded mulch mixture was created by E. LeRoy Brady, manager/chief landscape architect for the ADOT Roadside Development Section-Roadway Engineering.

Here are some of the components: hydraulically applied compost containing, among other elements, seeds of about 30 plants chosen specifically to suit the environment. These plants include desert senna, incienso brittlebush, desert marigold, arroyo lupine and more.  

The hydro-seeded mulch mixture feels spongy and light to walk on, almost like paper-mache. It stretches along the sides of the highway and parallels the guardrails. It follows the creek bank and hugs the sides of the culvert that carries the creek under SR 87.

Under the surface, on the banks of Slate Creek, are large quantities of massive stones and soil, known as riprap. The riprap is secured with grouted cement, allowed to cure, and then covered with the hydro-seeded mulch. Together, this prevents the earth from eroding and washing the road away. It also keeps Slate Creek’s water where is should be – in the creek, according to Lemmon, who works as a member of ADOT's Geotechnical Design Section-Bridge Group.

We know that most drivers won't even think about these bits of engineering the next time they escape to the cooler weather of the high country, but that's okay. If it's doing its job, you don't have to.