Quick answer
A Stack interchange truck accident usually happens on the curved ramps and merges where I-10 meets I-17 just west of downtown Phoenix, or at the Mini Stack where I-10 meets SR-51 and Loop 202. Speed on curves, load shifts and unsafe lane changes are common issues. Get medical care, note which ramp you were on and act before the carrier's data is lost. Arizona generally allows 2 years to file a lawsuit (A.R.S. 12-542).
A Stack interchange truck accident can happen in seconds: a trailer leans on a tight ramp, a semi merges into a lane that is already full, or traffic stops suddenly where several freeways come together. This page covers the Stack (I-10 and I-17) and the nearby Mini Stack (I-10, SR-51 and Loop 202), why crashes there can be complex, what to do afterward and which Arizona deadlines may apply. Start with our Phoenix truck accident guide for the full claim process. This is general information, not legal advice for your case.
Why the Stack and Mini Stack matter
These two interchanges sit at the center of the Phoenix freeway system. Traffic from the West Valley, north Phoenix, the East Valley and downtown all passes through them.
The Stack: I-10 and I-17
The Stack is the interchange where I-10 meets I-17 just west of downtown Phoenix, near 19th Avenue and McDowell Road. ADOT describes it (opens in a new tab) as a four-level interchange, so its ramps rise and curve over one another.
From the Stack, I-17 runs north as the Black Canyon Freeway toward Anthem and Flagstaff, and south toward the Durango Curve and the I-10 "Split" near Sky Harbor Airport. Our guide to I-17 truck accidents covers the rest of that freeway, including the northern grades.
The Mini Stack: I-10, SR-51 and Loop 202
East of downtown, south of McDowell Road and east of 16th Street, the Mini Stack connects I-10 with SR-51 (the Piestewa Freeway) heading north and Loop 202 (the Red Mountain Freeway) heading east. ADOT also describes it as a four-level interchange.
Between the two interchanges, I-10 passes through the Deck Park Tunnel beneath downtown Phoenix.
Why hazmat trucks may pass through the Stack
ADOT restricts hazardous cargo (opens in a new tab) in the I-10 Deck Park Tunnel because of limits on emergency response inside the tunnel, and Arizona's entry in the FMCSA hazardous materials route registry (opens in a new tab) lists I-17 as the alternative route. As a result, trucks carrying hazardous cargo across central Phoenix may use the Stack and I-17 instead of the tunnel.
Crashes involving hazardous cargo can raise extra issues, including higher federal insurance minimums. Under 49 CFR 387.9 (opens in a new tab), carriers of oil, hazardous waste and certain hazardous materials must carry at least $1,000,000, and some higher-risk hazardous loads require $5,000,000. For-hire interstate carriers of general freight in vehicles of 10,001 pounds or more must carry at least $750,000. See our guide to truck insurance limits.
Common causes of ramp and interchange crashes
Each crash depends on its own facts. At the Stack and Mini Stack, truck crashes may involve:
Speed on curved ramps. A loaded trailer has a high center of gravity. Taking a curve too fast can cause it to tip.
Shifting or poorly secured cargo. A load that moves on a curve can push the trailer over. Federal cargo securement rules appear in 49 CFR Part 393 (opens in a new tab), Subpart I.
Late lane changes. Drivers who miss their exit may cut across lanes at the last moment, and a trucker may not see a car in the trailer's blind spot.
Short merges. Traffic entering from one freeway may have limited room to merge with another.
Sudden slowdowns. Heavy trucks need more distance to stop when traffic backs up at a ramp.
Jackknifes. Hard braking on a curve can cause the trailer to swing out. Read more about jackknife, rollover and tire blowout crashes.
Driver fatigue or distraction, including phone use. Federal hours-of-service limits appear in 49 CFR 395.3 (opens in a new tab).
Multi-vehicle crashes
Because traffic is dense, a single truck crash at an interchange can involve several vehicles. Sorting out who hit whom, and in what order, often depends on camera footage, vehicle data and careful reconstruction.
Who may be responsible
Depending on the facts, the following parties may share fault for an interchange crash:
the truck driver
the motor carrier that employed or contracted the driver
the shipper or loader, if cargo was loaded or secured poorly
the owner of the trailer
a maintenance shop, for brake or tire problems
other drivers who contributed to the crash
Arizona generally makes each defendant responsible only for its own share of fault, under A.R.S. 12-2506 (opens in a new tab), with exceptions such as when parties acted in concert or one was the other's agent or employee. Our guide on who is liable in a truck accident explains each of these parties.
Evidence to protect
Interchange crashes often turn on exactly where each vehicle was and how fast it was moving. Helpful evidence may include:
the truck's engine control module data (speed, braking, throttle)
electronic logging device (ELD) data and dispatch records
forward-facing and driver-facing camera video
bills of lading and loading records, in a load-shift or rollover case
dash camera footage from other drivers
the crash report and photos of the scene
Federal rules require carriers to keep records of duty status and supporting documents for at least 6 months, under 49 CFR 395.8(k) (opens in a new tab). Video and engine data may be lost much sooner.
Our truck accident evidence guide explains how preservation letters work.
What to do after a crash at the Stack or Mini Stack
Stay safe and call 911. Interchange shoulders can be narrow. If you can move your vehicle out of traffic safely, do so; if not, stay buckled in and wait for help.
Get medical care. Some injuries do not show symptoms right away.
Note the ramp and direction. Write down which freeways you were moving between.
Photograph the truck if it is safe to do so: the company name, USDOT number, trailer number and plates.
Get the report number. Crashes on interstates and state highways are generally investigated by Arizona Department of Public Safety troopers, and DPS explains how to request a copy of a report (opens in a new tab).
Collect witness names and numbers, including drivers who may have dash cameras.
Avoid recorded statements to the trucking company's insurer. You do not have to give one.
Talk to a lawyer early. You can request a free case review.
If the truck did not stop
In a sideswipe or a merge crash, a truck driver may not realize a collision happened and may keep going. If that happens, write down everything you remember: the trailer color, any company name or logo, the direction of travel and the time.
ADOT has said it does not record its freeway camera feeds (opens in a new tab), so video usually has to come from business cameras or other drivers' dash cameras, and that footage may not be kept for long. If the truck cannot be identified, uninsured motorist coverage on your own auto policy may apply, if you bought it and depending on its terms. Arizona's UM statute, A.R.S. 20-259.01 (opens in a new tab), addresses claims involving an unidentified vehicle and may require corroboration when there was no physical contact.
What a claim may include
No lawyer can tell you in advance what a claim is worth. Value depends on the injuries, the evidence, the insurance available and how fault is divided. In Arizona, an injury claim may seek money for losses such as:
past and future medical bills
lost wages and reduced earning ability
pain, suffering and loss of enjoyment of life
vehicle and property damage
Keeping your medical appointments and saving bills, pay stubs and notes about daily limits can help document these losses.
Arizona law and deadlines
Time to file. Arizona generally allows 2 years from the date of injury to file a personal injury lawsuit, under A.R.S. 12-542 (opens in a new tab). Some exceptions can change that timing.
Public entities. If a public entity may share fault, for example through a work zone, a notice of claim is generally due within 180 days under A.R.S. 12-821.01 (opens in a new tab), and a lawsuit within 1 year under A.R.S. 12-821 (opens in a new tab).
Shared fault. Under A.R.S. 12-2505 (opens in a new tab), your damages may generally be reduced by your share of fault rather than barred.
Fatal crashes. A surviving spouse, child or parent, or the personal representative, may bring a wrongful death claim on behalf of the close family members listed in A.R.S. 12-612 (opens in a new tab). Arizona's constitution bars laws that cap damages for injury or death, under Article 2, Section 31 (opens in a new tab).
How we can help
We help people hurt in truck crashes at the Stack, the Mini Stack and across the Phoenix freeway system. Our Phoenix truck accident lawyer page explains our overall approach. We work on a contingency fee, so you pay no attorney fee unless money is recovered. The fee percentage and how case costs are handled depend on the case, and if there is no recovery you may still owe case costs. Attorney Gil Hacohen speaks English, Hebrew and Spanish.
Talk to a Phoenix truck accident lawyer for free
Tell us what happened. We'll review your situation and explain your options. There's no fee unless you recover money.
Frequently asked questions
Where exactly are the Stack and the Mini Stack?
According to ADOT, the Stack is the four-level interchange where I-10 meets I-17 just west of downtown Phoenix, near 19th Avenue and McDowell Road. The Mini Stack is east of downtown, south of McDowell Road and east of 16th Street, where I-10 meets SR-51 and the Loop 202 Red Mountain Freeway.
Why do trucks tip over on interchange ramps?
A tractor-trailer has a high center of gravity. Taking a curved ramp too fast, or carrying a load that shifts, can cause a rollover. Speed, load securement and the driver's training may all be examined.
Do hazardous materials trucks use the Stack?
Hazardous materials traffic is restricted in the I-10 Deck Park Tunnel, and Arizona's entry in the FMCSA hazardous materials route registry lists I-17 as the alternative route. That means hazmat trucks crossing central Phoenix may travel through the Stack.
The truck merged into me and kept going. What can I do?
Call 911, write down anything you saw, such as the company name, trailer color or USDOT number, and look for witnesses. ADOT says it does not record its freeway camera feeds, so business cameras and other drivers' dash cameras are often the better source of video. Your own policy's uninsured motorist coverage may also apply if you bought it, depending on its terms (A.R.S. 20-259.01).
Can more than one driver be at fault in a ramp crash?
Yes. Arizona uses comparative fault, and each defendant generally pays only its own share. Your damages may be reduced by any share of fault assigned to you, but generally not barred (A.R.S. 12-2505 and 12-2506).
How long do I have to bring a claim?
Arizona generally allows 2 years from the date of injury under A.R.S. 12-542. If a public entity may share fault, a notice of claim is generally due within 180 days (A.R.S. 12-821.01) and a lawsuit within 1 year (A.R.S. 12-821).