Connecticut’s mileage tax, formally the Highway Use Fee, charges commercial trucks a per-mile tax for driving on state highways at rates from 2.5 cents to 17.5 cents depending on gross vehicle weight. It applies to any truck weighing 26,000 pounds or more, whether the carrier is based in Connecticut or just passing through, and it’s filed quarterly through the Department of Revenue Services. The fee is set by Connecticut General Statutes § 12-493a and funds road maintenance tied to the wear heavy vehicles put on infrastructure.
Which Trucks Owe the Fee
A vehicle owes the Highway Use Fee if it meets two conditions: a gross weight of 26,000 pounds or more, and a classification between Class 8 and Class 13 under the Federal Highway Administration’s vehicle classification system.1Justia. Connecticut Code 12-493a – Highway Use Tax Class 8 covers heavy single-unit trucks. Class 13 covers large multi-trailer combinations. Every mile that vehicle travels on a Connecticut highway counts toward the quarter’s tax.
The statute defines a “carrier” broadly as anyone who operates or causes to be operated an eligible vehicle on Connecticut highways. Fleet owners are liable even when they never personally drive. Owner-operators hauling their own freight are liable too.
Out-of-state carriers get no interstate exemption. Every mile inside Connecticut counts, and existing IFTA or Motor Carrier Road Tax registration with the Department of Revenue Services does not cover you for the Highway Use Fee. You need a separate HUF account through the myconneCT portal.2Connecticut State Department of Revenue Services. Highway Use Fee Information Carriers who skip that step are out of compliance even when every other Connecticut account is current.
Who’s Exempt
Two categories of vehicles fall outside the fee despite meeting the weight and class thresholds.1Justia. Connecticut Code 12-493a – Highway Use Tax
- Government vehicles operated by the state of Connecticut, any of its political subdivisions, or the federal government. The exemption covers vehicles owned and operated by a government entity, not private contractors doing government work.
- Motor vehicles carrying milk or dairy products to or from a dairy farm that holds a license to ship milk. The exemption is narrow and covers transport directly between a licensed dairy farm and a processing destination; hauling dairy between warehouses or retail locations does not qualify.
What You Pay Per Mile
The rate rises with weight on a sliding scale. The lowest bracket, 26,000 to 28,000 pounds, pays $0.025 per mile. Rates climb in roughly $0.003 increments through each 2,000-pound bracket. The top of the schedule jumps sharply: 78,001 to 80,000 pounds pays $0.10 per mile, and anything over 80,000 pounds pays $0.175 per mile.1Justia. Connecticut Code 12-493a – Highway Use Tax
Selected brackets:
- 26,000–28,000 lbs: $0.025 per mile
- 38,001–40,000 lbs: $0.0423 per mile
- 50,001–52,000 lbs: $0.0596 per mile
- 64,001–66,000 lbs: $0.0798 per mile
- 78,001–80,000 lbs: $0.10 per mile
- 80,001 lbs and over: $0.175 per mile
The applicable rate depends on the truck’s gross weight, which includes the combined weight when a trailer is attached. If a truck pulls different trailers during the quarter, the highest registered gross weight for that vehicle during the period typically determines the rate. A Class 8 tractor running at 40,000 pounds across 5,000 Connecticut miles in a quarter would owe about $211.50 (5,000 × $0.0423).
Registering for a HUF Permit
You need a Highway Use Fee permit from the Department of Revenue Services before you can report miles or pay.2Connecticut State Department of Revenue Services. Highway Use Fee Information Registration happens through the myconneCT portal. You’ll need:
- Your Connecticut Tax Registration Number and your Federal Employer Identification Number, or Social Security Number for sole proprietors.
- The Vehicle Identification Number for every truck in your fleet that meets the weight and class thresholds.
- The specific gross weight of each vehicle, which decides the rate bracket.
Getting the weight right at registration matters. A vehicle assigned to the wrong bracket will produce wrong tax on every quarterly return, leading to either an underpayment or an overpayment that has to be corrected later.
Filing Quarterly Returns
The Highway Use Fee return is filed quarterly. The schedule changed from monthly to quarterly starting with the quarter beginning October 1, 2023. Each return is due on or before the last day of the month following the end of the quarter.2Connecticut State Department of Revenue Services. Highway Use Fee Information For a quarter ending March 31, the return and payment are due April 30.
Filing and payment are electronic only, through myconneCT. The system accepts ACH debit transfers and credit card payments. Once a submission is finalized and payment authorized, the portal issues a confirmation number worth saving.
Penalties for Late Filing or Nonpayment
Interest runs at 1% per month, or any fraction of a month, on unpaid tax until the balance is paid in full. The penalty for an incomplete return or late filing is 10% of the unpaid tax or $50, whichever is greater. A carrier that knowingly violates the Highway Use Fee provisions also faces a fine of up to $1,000.2Connecticut State Department of Revenue Services. Highway Use Fee Information
Records You Must Keep
Carriers have to keep records, receipts, invoices, and any supporting paperwork for the information reported on each return. The statute also requires a monthly list of every eligible vehicle the carrier operates on Connecticut highways during that month. All of these records must be retained for at least four years after the date of each month and produced for the Department of Revenue Services on request.1Justia. Connecticut Code 12-493a – Highway Use Tax
In practice that means a system that tracks mileage by vehicle and by state. GPS-based fleet management platforms handle this automatically. An owner-operator relying on manual logs should at minimum record daily odometer readings at Connecticut border crossings and trip destinations.