Connecticut Mileage and Vehicle Tax Records (2026): Bonus and Section 179 Add-Backs, TNC Rules and the AV Pilot Repeal
General information, not tax or legal advice. Talk to your tax preparer or attorney about your situation.
Connecticut starts from federal adjusted gross income, so a self-employed driver's federal mileage deduction carries over. If you claim federal bonus depreciation, you add back 100% and subtract 25% in each of the next four years; 80% of Section 179 is added back the same way. Rideshare companies register with the Department of Transportation.
Connecticut follows federal adjusted gross income but spreads the big first-year vehicle write-offs over five years. This guide covers what the Department of Revenue Services, the General Statutes and the Office of Legislative Research say as of October 16, 2026.
The federal baseline every Connecticut driver starts from
Most vehicle deductions begin on your federal return. If you're self-employed, you can generally use the standard mileage rate or actual expenses for the business share of your car (IRS Topic 510). For 2026 the business rate is 72.5¢ per mile for January 1 to June 30 (IR-2025-128 / Notice 2026-10) and 76¢ per mile for July 1 to December 31 (IR-2026-29 / Announcement 2026-11) (IRS standard mileage rates). EVs use the same rates; see the 2026 EV mileage rate guide. Most employees can't deduct unreimbursed car expenses federally (Topic 510). IRS Publication 463 asks for each business trip's miles, date, destination and purpose, plus total miles. Commuting stays personal (commuting vs business miles).
How Connecticut treats vehicle deductions
The 2025 Form CT-1040 instructions start with federal adjusted gross income on line 1, so a Schedule C vehicle deduction figured with the standard mileage rate or actual costs is already reflected.
Depreciation: two add-backs, four-year subtractions
- Bonus depreciation. On Schedule 1, line 36, you add back 100% of the Section 168(k) bonus depreciation deducted federally for the year. On line 48a, you subtract 25% of the amount you added back in each of the four preceding years.
- Section 179. On line 36a, you add back 80% of the Section 179 amount deducted in figuring federal AGI. Item 10 of the instructions' other-subtractions list lets you subtract 25% of that add-back in each of the four following years.
If you buy a vehicle and use actual costs, the Connecticut schedule differs from federal for five years. See robotaxi fleet depreciation and Section 179.
Rideshare (TNC) rules in Connecticut
Chapter 244c of the General Statutes covers TNCs. Section 13b-117 requires a TNC to register annually with the Commissioner of Transportation; since a 2025 amendment (P.A. 25-65), the fee depends on the company's number of active drivers: $5,000 for fewer than 50, $10,000 for 50 to 199, and $30,000 for 200 or more. Section 13b-118 requires an electronic receipt showing the trip's origin, destination, total time and distance, and fare. It bars cash payments, requires ride records to be kept at least three years, and limits drivers to 14 consecutive hours or 16 hours in any 24. Section 13b-121 sets a 30-cent fee per ride, paid by the TNC. In 2026, the General Assembly passed Public Act 26-63, which adds TNC requirements, including new safety measures effective January 1, 2027, per the Office of Legislative Research's summary (2026-R-0089). Keep your own receipts and annual summaries. See which rideshare miles count.
Robotaxis and autonomous vehicles in Connecticut
Connecticut's fully autonomous vehicle pilot program, Section 13a-260, was repealed effective July 1, 2025 (P.A. 25-65, § 66), per the 2026 Supplement to chapter 241. If you're planning a driverless fleet in Connecticut, check the Department of Transportation's current guidance and talk to an attorney. For fleet records, see robotaxi fleet tax basics.
What to keep in your Connecticut records
- Each business trip's date, start, destination, purpose and miles, plus total miles for the year (Pub 463); a weekly log counts as timely kept.
- Separate Business, Commute and Personal totals for Form 4562 Part V.
- Keep records until the period of limitations runs out, generally 3 years federally (IRS); ask your preparer about the state period.
- If you depreciate a vehicle: track each year's line 36 and 36a add-backs and the 25% subtractions over the next four years.
- For rideshare: save electronic receipts and annual summaries; TNCs keep ride records at least three years.
For the full list of log fields, see what the IRS asks you to record.
Example: 1,000 hypothetical business miles driven in September 2026 × 76¢ (IR-2026-29) = $760 at the federal standard rate. Miles driven in March 2026 would use 72.5¢ (IR-2025-128) instead, so keep each trip's date. Estimates, not tax advice.
One log for both returns
A Connecticut return doesn't call for a second mileage log; your preparer works from the same business, commuting and personal miles. CyberDeduct builds a mileage log around IRS Pub 463 from your Tesla's own trip and odometer data (Model S, 3, X, Y and Cybertruck). You connect your Tesla account once through Tesla's standard account sign-in (OAuth); CyberDeduct never sees or stores your password. Home/work rules and route templates label most trips Business, Commute or Personal; you tap to change any label and confirm the purpose. The dashboard shows your business-use percentage and warns you on the 28th if you're under 50%. You export a PDF or CSV log plus a Form 4562 Part V worksheet for your preparer. See how the log is built or see plans.
Sources (checked October 16, 2026)
- Connecticut Department of Revenue Services, 2025 Form CT-1040 instructions
- Conn. Gen. Stat. chapter 244c (TNCs)
- Office of Legislative Research, 2026-R-0089 (PA 26-63 summary)
- Conn. Gen. Stat. chapter 241, 2026 Supplement
- IRS, Standard mileage rates; IRS Publication 463; IRS Topic 510
Frequently asked questions
Does Connecticut use my federal mileage deduction?
Generally yes for the self-employed. Form CT-1040 starts from federal adjusted gross income, which already reflects Schedule C vehicle expenses.
How does Connecticut handle bonus depreciation?
You add back 100% of federal bonus depreciation (Schedule 1, line 36) and subtract 25% of it in each of the next four years (line 48a).
How does Connecticut handle Section 179?
You add back 80% of the federal Section 179 deduction (line 36a) and subtract 25% of that add-back in each of the next four years.
How long do Connecticut TNCs keep ride records?
At least three years, under Conn. Gen. Stat. § 13b-118.
Does Connecticut still run an autonomous vehicle pilot?
No. Section 13a-260, the pilot program, was repealed effective July 1, 2025 (P.A. 25-65, § 66).
This article is general information, not tax or legal advice. Talk to your tax preparer or attorney about your situation. State laws and bill status change; check the linked sources for the current text.
CyberDeduct is an independent product of LIKE LLC and is not affiliated with or endorsed by Tesla, Inc. Tesla is a trademark of Tesla, Inc.