IFTA Audit: What Triggers One and How to Survive It

An IFTA audit isn't something that happens only to carriers who are cheating. It happens to carriers with missing records, inconsistent mileage reporting, and math that doesn't add up — even when the underlying numbers are honest.

Understanding what triggers an audit and what auditors are actually looking for is the best way to make sure one never finds a problem.

What IFTA Auditors Are Checking

IFTA auditors — who work for your base jurisdiction, not the federal government — are verifying that the miles and fuel you reported on your quarterly returns match the records you actually kept during the period being audited. They're specifically looking at:

• Total miles traveled (from trip records, odometer logs, or ELD data)
• Miles by jurisdiction (the breakdown that determines your fuel tax allocation)
• Total gallons purchased (from fuel receipts or fuel card statements)
• Gallons purchased by state (which drives the credit/debit calculation)
• Calculated vs. reported figures — does your supporting documentation produce the same numbers you submitted?

Auditors will also check whether your records are legible, complete, and whether they cover every vehicle registered under your IFTA license.

What Triggers an IFTA Audit

Base jurisdictions select carriers for audit through a mix of automated screening and random selection. The most common audit triggers are:

1. Miles Per Gallon Inconsistency

Your MPG is calculated from your quarterly returns: total miles divided by total gallons. An unusually high or low MPG — say, 14 MPG for a loaded semi, or 3 MPG — will flag your return for review. Most jurisdictions are looking for MPG figures that fall outside a reasonable range for the vehicle type.

A single bad quarter from a fuel card error or a recording mistake can be enough to trigger a letter.

2. Large Variations Between Quarters

If your reported miles or fuel swing dramatically from one quarter to the next without explanation, auditors notice. A carrier that reports 35,000 miles in Q1 and 9,000 miles in Q2 without seasonal explanation (a documented shutdown, for example) looks like missing miles.

3. Zero Miles in a Jurisdiction You Likely Passed Through

If your routes regularly take you through Indiana but you're not reporting any Indiana miles, that's a red flag. Jurisdiction routing is one of the things auditors cross-check against general geography and your customers' locations.

4. Estimated Mileage

Using odometer-based estimates instead of actual trip records is permitted as a last resort — but it invites audit and leaves you without detailed supporting documentation if auditors want to drill down.

5. Random Selection

Some audits are simply random. There's no audit trigger other than your number coming up. These can happen even to carriers with clean, consistent returns.

6. Complaint or Referral

A complaint from another jurisdiction, or a discrepancy identified during a roadside inspection, can initiate an audit.

The IFTA Record Retention Rule

IFTA requires that you keep your supporting records for four years from the filing deadline for each quarterly return. This includes:

• Individual trip records or ELD reports showing miles by jurisdiction, date, vehicle, and driver
• Fuel receipts or fuel card statements showing gallons purchased, vendor, location (state), date, and vehicle
• Monthly fleet summaries or mileage schedules
• Copies of your filed quarterly returns

If you can't produce these for every quarter being audited, auditors are permitted to estimate your liability — and their estimates are not in your favor.

What a Trip Record Must Include

Trip records (also called driver trip logs or distance records) must document:

• Date of trip
• Origin and destination
• Routes traveled
• Odometer or hubometer readings at start and end
• Total miles and miles per jurisdiction
• Vehicle identification (plate number or unit number)
• Driver name

ELD data satisfies most of these requirements automatically. If your ELD is FMCSA-registered and your provider can export jurisdiction-level mileage, that's your best documentation. Automatic mileage tracking by jurisdiction eliminates the manual recording error that causes most IFTA problems.

What a Fuel Receipt Must Include

For a fuel purchase to be credited on your IFTA return, the receipt must show:

• Date of purchase
• Seller's name and address
• Number of gallons purchased
• Fuel type (diesel, gasoline, etc.)
• Price per gallon
• Vehicle unit number or plate number

Fuel card statements from major fleets (Love's, Pilot, TA, etc.) typically include all of this and serve as valid IFTA records. Personal credit card receipts from a pump — if they show the location and gallons — are also valid. A receipt that only shows a dollar total without gallons is not sufficient.

How to Prepare Before an Audit Letter Arrives

The best time to get audit-ready is every quarter, not when the letter arrives.

Quarterly reconciliation

Before you file each IFTA return, reconcile your trip records against your fuel records:

• Do your total miles match what your odometer moved?
• Does your jurisdiction breakdown add up to your total miles?
• Do your reported gallons match your fuel card statement total?

If the numbers don't reconcile before you file, they won't reconcile during an audit.

Track fuel by state as you purchase it

Don't rely on end-of-quarter reconstruction. Your fuel tracker should record the state of purchase at the time of the transaction. Fuel purchased in Illinois and fuel purchased in Ohio count differently in your IFTA tax calculation — one state may have a higher tax rate than the other, and the net result is either a payment or a refund for each jurisdiction.

Keep your records in one place

Paper receipts in a glove box get lost, faded, or destroyed. Digital records — fuel card statements downloaded monthly, ELD exports archived by quarter — are more durable. Expense tracking that stores fuel receipts digitally gives you a complete record that's searchable and exportable if you're ever asked to produce documentation.

What Happens During an Audit

An IFTA audit typically starts with a letter from your base jurisdiction requesting records for a specified period (often the last four quarters or longer). The audit may be conducted by mail/document submission, or it may involve an in-person visit to your office.

Step 1: Gather every record for the audit period. Trip records, fuel receipts, IFTA returns, and any ELD data.

Step 2: Reconcile your records against your filed returns before submitting anything. If you find a discrepancy, it's better to identify it now than have the auditor find it.

Step 3: Respond completely and on time. Missing the audit response deadline or submitting incomplete records makes everything worse.

Step 4: If there's a deficiency, you'll receive an audit report showing the additional tax owed, plus interest and possibly penalties. You have the right to appeal if you believe the findings are wrong.

Most audits that result in minimal or no additional tax are audits where the carrier had complete records and filed accurate returns. The records are the defense.

Audit Results and Penalties

If an audit finds that you under-reported miles or over-reported fuel (which would reduce your net tax), you'll owe the additional tax plus interest. Penalties vary by jurisdiction but commonly run around 10% of the deficiency. Fraud — deliberately falsifying records — carries much steeper penalties including possible license revocation.

Under-reported miles are the most common deficiency. It usually comes from trip records that don't capture all miles driven, or from estimated mileage that was too low.

Truck Command captures mileage by state automatically from your load records, tracks fuel by jurisdiction, and keeps your IFTA reporting accurate quarter by quarter. If an audit letter arrives, your records are already organized and exportable. Plans start at $20/month with a 14-day free trial — no credit card required.