Licensing roadside units: what to file, where, and for how many sites
A roadside unit transmits under an FCC license (47 CFR Part 90 subpart M). The on-board units in vehicles need none: Part 95 subpart L licenses them by rule. One license per operating entity covers its whole area. Every RSU is then registered under that license before it transmits. This page tells you which filing fits a single intersection, a corridor, a county fleet or a trailer, and the planner below turns your numbers into a checklist and a site worksheet.
ITS Roads prepares and files these for agencies. This page is a planning aid, not legal advice. Rule text was checked against the eCFR in October 2026; the FCC can change forms, fees and procedures, so read the current public notice before you file.
What you get and who issues it
The license
A non-exclusive geographic area license (47 CFR 90.389(a)). Issued by the FCC Wireless Telecommunications Bureau, applied for on FCC Form 601 in the Universal Licensing System (ULS). Radio service code IQ for public safety eligible entities, QQ for everyone else, per the FCC guide and DA 26-1074. A government applicant gets its legal jurisdiction as the area; other applicants pick county, state or nationwide.
The RSU registrations
One row per RSU site, filed as Form 601 Schedule M under the license with an attachment of type "C-V2X RSU Registration" (DA 25-125). A registration takes effect when the FCC posts it on ULS, and the RSU may not transmit before that (47 CFR 90.389(b)).
The FRN
An FCC Registration Number from CORES. Every filing and every fee payment hangs off it. The FRN must belong to the entity that will hold the license, not to the contractor filing on its behalf.
Equipment certification
The RSU must be FCC certified under Part 2 and Part 90. You do not file for this; the vendor did. Ask for the FCC ID and check that the grant covers 5895 to 5925 MHz at the power you plan to run.
NTIA coordination
Federal radiolocation sites listed in 47 CFR 90.387(b) have coordination zones around them (30 locations in the current table, with radii from 2 to 195 km). An RSU inside a zone needs NTIA approval before it operates, and it gets no protection from federal radiolocation that was there first.
Which filing for which deployment
The answer is the same shape every time. One license per operating entity, reused for every site it will ever build. One Schedule M row per RSU site. All sites can go in one application. What changes is the count, the timing and a few special notes.
| Deployment | License needed | What to register | Batch or one at a time | Timing | Fees | Special notes |
|---|---|---|---|---|---|---|
| A single intersection | One IQ or QQ geographic license for the entity. If the agency already holds one, reuse it. | One Schedule M row: coordinates, antenna height, gain, EIRP, channel. | License and registration are separate steps; the registration is one row. | File the license first. The registration takes effect when posted on ULS; no transmitting before that. Build within 12 months of the effective date or the registration cancels (90.155(i)). | Government and nonprofit public safety applicants: exempt (1.1116(b)). Others: the site-based fees in the FCC guide. | The smallest filing there is. Most of the work is getting the antenna height and EIRP right. |
| A corridor of N intersections | Still one license. The corridor sits inside the entity's licensed area. | N Schedule M rows, one per RSU site. | All N rows can go in one Form 601 application or modification. Later sites are added by modification. Nothing in the rules limits the count. | Same as above. Each registration has its own effective date and its own 12 month clock. | Same as above. | Survey every site before filing: coordinates in NAD83, antenna radiation center above the roadway surface. A corridor filed in one batch gets one grant date for all the clocks. |
| A county or statewide fleet | One license. A state DOT's area is the state; a county's is the county. | One row per RSU site, however many there are. | Batch them. File the sites that are surveyed now and add the rest by modification as they are ready. | Do not register sites that will not be built within 12 months; they cancel and have to be refiled. | Same as above. | Keep one master worksheet (the CSV below) under version control. Delete rows for RSUs taken out of service; the rules put that on the licensee (90.389(b)). |
| A portable work zone trailer | One license, the same one. | A row for every location where the unit will transmit. Subpart M has no mobile RSU authorization; each registration is a fixed site. | Known locations can be batched in advance. A new location is a modification. | Each location must be posted before the trailer transmits there. | Same as above. | Keep a log of where the trailer transmitted and under which registration. For short-lived or temporary locations ask the Wireless Telecommunications Bureau contact named in DA 26-1074 before you file; the rules do not describe a temporary RSU site. |
| A toll gantry | One license held by the toll authority (IQ per the FCC guide) or its operator (QQ). | One row per gantry RSU. | Batch the plaza or the whole facility. | Same as above. | Authority: exempt per the FCC guide. Private operator: site-based fees. | An antenna over the roadway: the height that counts is the radiation center above the roadway surface (90.391(c)), not above the ground beside it. Above 8 m the EIRP must come down; 15 m is the limit. |
| A university or vendor test site | One QQ license for the university or company (90.388(b), via 90.20, 90.33 or 90.35 eligibility); area is a county, state or nationwide. | One row per test RSU. | One application. | Same as above. | Site-based fees in the FCC guide unless the entity qualifies as a government or nonprofit public safety applicant. | Test sites are non-priority communications: a later-registered RSU must accommodate an earlier one if a dispute arises (90.390(c)). Register early. |
| A DSRC fleet converting before December 14, 2026 | The existing IQ or QQ license. No new license. | Modify each existing DSRC RSU registration to C-V2X with a Schedule M modification and the "C-V2X RSU Registration" attachment (DA 25-125, DA 26-1074). | All RSUs in one modification application. | DSRC transmitting must stop on December 14, 2026. After that date the FCC deletes DSRC RSUs from IQ and QQ licenses; a deleted RSU has to be registered again as new. | Same as above. | In ULS select the whole upper 30 MHz (the DSRC channel rows for 5895 to 5925 MHz) and clear the lower-band DSRC channels. Verify the radios on the new channel plan before the filing goes in. |
Turn your deployment into a filing checklist
Set the inputs. The checklist, the fee estimate, the power consequence of the antenna height, the timeline and the site worksheet update as you type. Nothing leaves your browser.
One row per Schedule M registration with the columns a row needs. Fill it from the survey, then transcribe into ULS. Coordinates in NAD83 decimal degrees; heights in meters; the roadway height is the one the EIRP rule uses.
The systems and the documents
Filing systems
- Universal Licensing System (ULS): Form 601 and Schedule M are filed online here. Sign in with the agency's FRN, then License Manager for an existing license or Online Filing for a new application.
- CORES: get or look up the FRN, and pay any fee after the application is submitted.
- No frequency coordinator step for this band: ITS applications and RSU registrations are exempt under 47 CFR 90.175(j)(16).
- NTIA coordination, when a site is inside a 90.387(b) zone, goes through the FCC as part of the registration; the RSU waits for NTIA approval.
Read before filing
- FCC DA 25-125 (February 2025): the transition public notice with the Schedule M filing instructions and the attachment type to use.
- FCC DA 26-1074 (October 5, 2026): the reminder that DSRC authority ends December 14, 2026, with the bureau contacts.
- FCC 24-123: the Second Report and Order that wrote the current rules.
- 5GAA 5.9 GHz FAQ, Appendix B: the click-by-click walkthrough of the ULS screens.
- The wiki article on this site: the rules in one page, with the technical limits table.
Common mistakes
- Transmitting before the registration posts. The grant email is not the effective date; the ULS posting is.
- Antenna above 15 m. There is no waiver path in the rule. Between 8 and 15 m the EIRP comes down by 20 log10(h/8) dB.
- Forgetting the trailer's new site. A portable RSU at an unregistered location is an unlicensed transmitter.
- Letting a registration cancel at 12 months. The cancellation is automatic (90.155(i)). Register when the pole is funded, not when the plan is drawn. Notify the FCC when the unit is placed in operation.
- Registering under a contractor's FRN instead of the agency's. The license then belongs to the contractor and has to be assigned later.
- Mixing up IQ and QQ. IQ is the public safety service; a private company that files IQ gets returned.
- Not deleting sites taken out of service. The licensee has to delete them; they otherwise hold priority against neighbors and clutter the next modification.