You filed UCR in November with four trucks. In March you bought three more, or sold two, or leased on a couple of owner-operators. Do you owe an updated UCR? The short answer from the UCR Plan is no — and the longer answer explains what you should update instead, how the change shows up next year, and where the one real exception (a count that was wrong on the day you filed) sits. The counting rules themselves are in how to count your UCR fleet; this guide is about what happens after the count changes.
Does adding or removing trucks change this year’s UCR?
No. The UCR Plan’s FAQ asks the question almost word for word — will a carrier be required to file a supplemental report and fees if the size of its fleet increases or decreases during the year? — and answers: “No. UCR fees will be set through a graduated structure of rates according to the number of commercial motor vehicles operated by a motor carrier ... during the preceding year. Changes during the UCR Agreement registration year in the number of vehicles operated will not be reflected until the following year and the carrier will not need to report them currently.”
That follows from how the statute defines the count. Under 49 USC §14504a(f)(3), your bracket rests on one of two backward-looking numbers: the vehicles you indicated on your most recently filed MCS-150, or the total you owned or operated for the twelve months ending June 30 of the year before the registration year. Neither number can move because of a truck you bought in March. So the fee you paid for 2026 is the fee for 2026; there is no supplemental filing when the fleet grows, and — the other half people ask about — no refund or bracket drop when it shrinks. The Plan does not prorate or refund for downsizing, which the refunds and proration guide covers in detail.
What “updating your UCR” actually means
The phrase gets used for three different things, and only one of them touches your current UCR registration.
- Updating your MCS-150 with FMCSA.This is the update you should make when your fleet, address, or entity details change. It is a separate FMCSA filing, done in the Motus registration system, and it is what feeds next year’s UCR default. More on it below.
- Setting next year’s bracket. This happens automatically at renewal, when you choose which counting basis to use for the new registration year. Trucks added this year enter that count; trucks sold can leave it.
- Correcting a filing that was wrong when made. If you reported four vehicles for 2026but actually owned or operated eight during the counting period you elected, that is not a mid-year change — it is an error on the registration itself, and it should be corrected through your base state or the filer who submitted for you, with the bracket difference paid.
The line between two and three matters. Growth after you filed is not reportable this year. A count that was low on the day you filed is a bracket retreat, and bracket retreats are what participating states are required to audit — the UCR audits guide explains how the audit lists are built.
How fleet changes flow into next year’s bracket
| Fleet event during 2026 | This year’s UCR (2026) | Next year’s UCR (2027) |
|---|---|---|
| Bought or leased (30 days or longer) additional power units | No supplemental filing, no added fee. | Counted on the MCS-150 basis once you update it, and in the June-30 actual (July 1, 2025–June 30, 2026) if acquired before that June 30. |
| Sold or parked power units | No refund, no bracket drop. | Update the MCS-150 so the default count is right; or elect the June-30 actual if it is lower, keeping records for a UCR-2 vehicle list. |
| Some units now run exclusively intrastate | No change to the filed year. | May be excluded under §14504a(f)(3) if they never crossed a state line; your base state can request a UCR-1 list identifying them. |
| Acquired another carrier’s fleet | Their filing covers their USDOT number for the year; yours covers yours. | Inherited units count in your fleet from the date they came under your authority. |
| Filed the wrong count for the period you elected | Correct it through your base state or filer; pay the bracket difference. | File on the right basis; a corrected MCS-150 removes the mismatch auditors look for. |
The dollar stakes are the bracket boundaries. Two trucks to three moves you from $46 to $138; five to six is $138 to $276; twenty to twenty-one is $276 to $963. A fleet sitting on one of those lines has real money riding on which basis it elects next year, and on whether the MCS-150 that pre-fills the form is current.
The MCS-150 connection
The National Registration System does not ask you to count from scratch each fall. Missouri DOT’s UCR guidance describes what most carriers see: the vehicle count on your renewal form “is taken from the number of commercial motor vehicles listed on the last MCS-150 you submitted with the Federal Motor Carrier Safety Administration.” You can override it — elect the June-30 actual instead, or subtract exclusively-intrastate units — but the default is whatever FMCSA has on file. If that number is stale and high, you overpay by default; if it is stale and low, the bracket you accept does not match the fleet you run, and the mismatch is visible to any auditor comparing the two records.
So the update that matters is the MCS-150. FMCSA requires it at least every 24 months on a schedule tied to the last digit of your USDOT number (49 CFR 390.19T) and accepts an updated filing any time your information changes; since 2026 it is filed in FMCSA’s Motus registration system. Tennessee’s Department of Revenue tells carriers to update the MCS-150 beforefiling UCR for exactly this reason. Do it when the fleet changes, and again before the October renewal window, and next year’s UCR takes care of itself. If you would rather not track any of this, FastUCR (a private third-party filing service, not a government agency) checks your count against your MCS-150 before submitting — $80 for the smallest bracket, $70 a year on auto-renew.
Fleet changed since last year?
We validate your vehicle count against your MCS-150 and the June-30 actual before the filing goes in, so you land in the right bracket — not the default one. Federal fee and service fee itemized; same-business-day submission.
File UCR NowThe audit angle
Because mid-year growth is not reportable, nobody audits you for adding trucks. What gets audited is the count you certified. Participating states must audit registrants, and the pattern the Plan tells them to look for is a bracket lower than the carrier’s own MCS-150 implies. If you filed on the June-30 actual because it was lower, keep the proof that makes the lower number true — bills of sale, lease terminations, plate cancellations — and be ready to produce the UCR-2 vehicle list (make, model or GVWR, plate, VIN) your base state may request; the UCR-1 list does the same job for excluded intrastate-only units. Both forms are signed under penalty of perjury. Missouri’s guidance adds one more detail: equipment leased for 30 days or more counts, so an owner-operator leased on for the season is in your count next year, not just your own titled trucks. The tier-by-fleet-size guide walks the boundary cases.
Address, name, and entity changes
The other “update my UCR” question is a moved office or a new company name. Change it at the source: the UCR record is keyed to your USDOT number and carries company information from your FMCSA registration, so a name or address change made through the MCS-150 in Motus flows to your next UCR filing. Two cases need more than that. A brand-new legal entity — a sole proprietor forming an LLC, say — gets a new USDOT number, and UCR does not transfer between numbers; the new entity files its own registration for the current year. And a move that changes your principal place of business to another state changes your base state only at annual renewal, under the rules in the base state guide.
Bottom line:trucks added or sold after you file do not change this year’s UCR — no supplemental filing, no refund. They change next year’s count, which the system pre-fills from your last MCS-150. Keep the MCS-150 current in Motus, elect the cheaper legal basis at renewal with the records to prove it, and treat a count that was wrong on filing day as the one thing you do fix now.