Arizona Gas Tax: Rates, Refunds, and IFTA Rules

The Arizona gas tax is 18 cents per gallon on gasoline and either 18 or 26 cents per gallon on diesel, depending on the size of the vehicle burning it. Add the federal excise tax and you’re paying at least 36.4 cents per gallon on regular gasoline before you factor in any county transportation levy. Heavy-truck diesel runs at least 50.4 cents per gallon in combined state and federal tax. Every dollar of the state share goes into a dedicated transportation fund that can only be spent on roads and highways.

State Rates by Fuel and Vehicle Type

Arizona Revised Statutes § 28-5606 sets the rate for all motor fuel consumed in the state. Regular gasoline is taxed at 18 cents per gallon everywhere in Arizona.¹ Diesel and other “use fuels” are taxed at the same 18-cent rate when they power a light-class vehicle like a pickup truck.

The rate jumps to 26 cents per gallon for “use class” vehicles, which Arizona defines as trucks, tractors, or passenger vehicles with a declared gross weight above 26,000 pounds or more than two axles.² The higher rate reflects the heavier wear big rigs put on pavement. Certain vehicles under § 28-5432, such as qualifying school buses and government-owned vehicles, stay at 18 cents even when they’d otherwise fall into the use class.¹

Alternative fuels are fully exempt from the use fuel tax. If your vehicle runs on electricity, natural gas, propane, or hydrogen, the use fuel tax does not apply.¹

Legally the fuel tax is a tax on the consumer, but the state collects it from suppliers and distributors upstream. Distributors add it to the wholesale price, so by the time you’re pumping gas the tax is already built into the posted price.³

Federal Tax Stacked on Top

The price at the pump also includes the federal excise tax under 26 U.S.C. § 4081. The federal rate is 18.3 cents per gallon on gasoline plus a 0.1-cent Leaking Underground Storage Tank surcharge, for a total of 18.4 cents. Diesel carries a federal rate of 24.3 cents plus the same 0.1-cent surcharge, totaling 24.4 cents.⁴ These federal rates have not changed since 1993.

Add it up and an Arizona driver filling a passenger car with regular gasoline pays at least 36.4 cents per gallon in taxes. A heavy-vehicle operator buying diesel pays at least 50.4 cents per gallon.

County Transportation Taxes

Several counties layer additional voter-approved transportation taxes on top of the state rate. Under A.R.S. § 42-6106, a regional transportation authority can levy a county transportation excise tax if a majority of voters approve it at a countywide election.⁵ A.R.S. § 42-6107 provides a similar mechanism specifically for county road funding.⁶

Maricopa and Pima counties both have active transportation excise taxes of this type. They’re structured as sales taxes rather than per-gallon fuel taxes, but they still push up the total cost of a fill-up. Rates depend on voter-approved ballot measures and change when those measures expire or are renewed, so the amount varies by county and over time. Drivers in metro Phoenix and Tucson consistently pay more per gallon than drivers in rural counties without these levies.

Where the Money Goes

All state fuel tax revenue flows into the Arizona Highway User Revenue Fund (HURF) after exemptions and refunds are subtracted.⁷ The state treasurer then distributes those dollars under a formula in A.R.S. § 28-6538:

State highway fund: 50.5 percent
Cities and towns: 27.5 percent
Counties: 19 percent
Cities with populations over 300,000: an additional 3 percent⁸

Within the state highway fund’s share, a portion is earmarked for controlled-access highways in Maricopa and Pima counties, split 75/25 between the two.⁸

The Arizona Constitution restricts HURF money to transportation purposes. If the state auditor general finds that a city or county spent HURF dollars on something else, the state treasurer withholds future distributions until the jurisdiction proves it replenished the diverted amount from its own general revenue.⁷ Counties and cities are also barred from spending HURF money on traffic law enforcement or traffic safety programs.

Exemptions and Refunds

Arizona exempts fuel that isn’t used to propel a vehicle on public highways. Under A.R.S. § 28-5610, common exempt categories include fuel burned in farm tractors and agricultural implements, construction equipment like graders and pavers that only touch a highway incidentally, and dyed diesel sold for off-road use.⁹

In most cases you still pay the tax at the pump and claim a refund afterward. The exemption statute itself says a person claiming an exemption “shall perfect the exemption by claiming a refund” under § 28-5612. The main exception is dyed diesel, which is sold tax-free at the point of sale because the red dye signals the fuel is restricted to off-road use.¹⁰

How to Claim a Refund

The refund process runs under A.R.S. § 28-5612. File an application with ADOT within six months of the purchase date. ADOT uses different forms depending on fuel type: Form 96-0466 covers motor vehicle and aviation fuel refunds, and Form 96-0168 covers use fuel purchased for off-highway purposes.¹¹

Every application must include copies of purchase invoices showing the date, seller’s name and address, gallons, fuel type, and price per gallon. For off-highway refunds you also submit an equipment list on Form 96-0161, and you must keep the original invoices for at least three years.¹² ADOT won’t process a claim for less than $10 in aggregate taxes within a six-month period.

One quirk worth knowing: if you claim a use fuel refund, ADOT first checks whether you owe any transaction privilege (use) tax on the same fuel under Title 42. If you do, the department offsets your refund by the amount owed and sends you only the difference.

Dyed Diesel and Other Penalties

Red-dyed diesel exists so off-road users like farmers, miners, and construction crews can buy diesel without paying the highway fuel tax. The dye is added at the supplier level and serves as an instant visual marker that the fuel isn’t legal for highway use.¹⁰

Running dyed diesel in a highway vehicle carries steep penalties. Under A.R.S. § 28-5647, the civil penalty for a first offense is $1,000 or $10 per gallon of dyed diesel involved, whichever is greater. Repeat violations multiply that amount by the number of occurrences.¹³ Both the business entity and any officer, employee, or agent who knowingly participated are jointly liable. Criminal charges can be added on top.

ADOT’s Fuel Tax Evasion Unit also investigates broader offenses: fuel tax evasion, obstructing enforcement, attempting to alter or remove dye from fuel, and filing false refund claims. If any part of a tax deficiency is due to fraud, the civil penalty is 50 percent of the tax assessed, on top of the taxes and interest already owed.² Willful violations can lead to criminal prosecution and imprisonment.

Interstate Carriers and IFTA

Commercial operators running across state lines file under the International Fuel Tax Agreement instead of paying at each state’s pump rate. IFTA lets you file one quarterly return with your base jurisdiction covering every state you drove through. Arizona-based carriers get an IFTA license through ADOT’s Motor Carrier Services division, and eligibility requires a USDOT number, active operating authority, Corporation Commission registration for business entities, proof of an established Arizona business location (virtual offices don’t qualify), and a surety or cash bond on file with ADOT.¹⁴

Quarterly IFTA returns are due April 30, July 31, October 31, and January 31. Late filings or underpayments trigger a penalty of $50 or 10 percent of the delinquent taxes, whichever is greater, and interest accrues on top of that.¹⁵

Fuel Purchased on Tribal Lands

Tribal sovereignty puts fuel purchases on reservation land under a separate set of rules. A.R.S. § 28-401 authorizes ADOT to enter into intergovernmental agreements with tribes establishing how taxes paid on exempt motor fuel purchases within tribal lands are refunded.¹⁶ The specifics vary by tribe, so the effective tax treatment of a fill-up on a reservation depends on the particular compact between that tribe and the state.

1
Arizona Legislature. Arizona Code 28-5606 – Imposition of Motor Fuel Taxes
2
Arizona Department of Transportation. Fuel Tax Evasion Unit
3
Joint Legislative Budget Committee. Motor Vehicle Fuel Tax
4
GovInfo. 26 USC 4081 – Imposition of Tax
5
Arizona Legislature. Arizona Code 42-6106 – County Transportation Excise Tax
6
Arizona Legislature. Arizona Code 42-6107 – County Transportation Excise Tax for Roads
7
Arizona Legislature. Arizona Code 28-6533 – Arizona Highway User Revenue Fund
8
Joint Legislative Budget Committee. FY 2026 Baseline – Arizona Department of Transportation
9
Arizona Legislature. Arizona Code 28-5610 – Exemptions
10
Arizona Department of Transportation. Red-Dyed Diesel Fuel in Arizona
11
Arizona Department of Transportation. Fuel Tax Information – Refunds
12
Arizona Department of Transportation. Use Fuel Off Highway Refund Application
13
Arizona Legislature. Arizona Revised Statutes 28-5647 – Dyed Diesel Prohibited
14
Arizona Department of Transportation. Motor Carrier Services
15
Arizona Department of Transportation. IFTA Tax Filing Online Service
16
Arizona Legislature. Arizona Code 28-401 – Intergovernmental Agreements