Section 107.145 is the rule for people inside moving vehicles. A small unmanned aircraft may operate over a human being in a moving vehicle only when the operation already qualifies as Category 1, 2, 3, or 4, and then only on the extra terms in that section. For Category 1, 2, or 3, the aircraft must, throughout the operation, remain within or over a closed or restricted-access site where every person in a moving vehicle on that site is on notice that a small unmanned aircraft may fly over them, or the aircraft must not maintain sustained flight over moving vehicles.
The rule
Read §107.145(a) first. The flight still has to be a real category operation: §107.110, §107.115, §107.125, or §107.140. Flying over a car does not create a category. The category pages, starting with operations over people, are where weight, injury standards, declarations, and airworthiness live. This page is the moving-vehicle overlay.
Section 107.145(b) is an or. For Category 1, 2, or 3, either the operation stays inside or over the closed or restricted-access site with notice to the vehicle occupants, or the aircraft does not maintain sustained flight over the moving vehicles. Speed limits, a 400-foot bubble around the cars, and a LAANC authorization are not the test in that paragraph. Category 4 is paragraph (c): a Part 21 airworthiness certificate, and operation inside Flight Manual limitations that do not prohibit flight over people located inside moving vehicles.
Section 107.25 is a different sentence. It restricts operating the small unmanned aircraft system from a moving aircraft, and from a moving land or water vehicle unless the aircraft is flown over a sparsely populated area and is not transporting another person's property for compensation or hire. The pilot can be standing on the sidewalk while §107.145 still applies to the occupants of the cars below. The pilot can be in a moving boat while §107.25 applies to the launch and §107.39 plus Subpart D still apply to people. Keep the pair separate on the operating from a moving vehicle page.
How to apply it
Decide which branch of §107.145(b) you are using before you frame the shot. A closed or restricted-access site, with occupants on notice, can support sustained flight over vehicles that stay on that site. A public highway, an open parking lot used by the public, and a parade route are not that site. On those roads the second branch is the one you have: do not maintain sustained flight over the moving vehicles.
Sustained flight over the vehicles is hovering above them, flying back and forth over them, circling over them, or pacing one vehicle and holding position overhead. A single brief crossing during a point-to-point flight, including one perpendicular pass over a public road, can fit the second branch when you do not hover, circle, or come back over the traffic. The aircraft still has to be eligible for its category for the whole operation, which for Category 2 means the declaration, the label, and the operating instructions described on the Category 2 page.
A highway tracking shot
You are on foot beside an open public highway with a Category 2 aircraft, and the client wants traffic footage. No waiver is on file. The highway is not a closed or restricted-access site, so notice to drivers does not open the first branch. One perpendicular crossing, made while the aircraft is traveling from the job on the east side to the job on the west side, without pacing or hovering, matches the profile §107.145 allows.
The two-minute tracking shot does not. Matching a truck's speed and holding directly above it maintains sustained flight over that moving vehicle. Hovering over the centerline while cars pass underneath does the same thing. Both fail on a site that is not closed or restricted, even if the aircraft is otherwise a legal Category 2 machine and even if you never leave the ground.
The trap
The exam item writes three tempting substitutes for the or in §107.145(b): Remote ID plus staying within 400 feet of the vehicles, a speed under 25 miles per hour, and an altitude above 100 feet. None of those is the regulation. The regulation is the closed or restricted-access site with occupants on notice, or no sustained flight over the moving vehicles.
The scenario item then offers the illegal profiles as if they were short. Hovering the centerline and pacing a truck for two minutes are sustained flight. The legal profile on that open corridor is the single perpendicular crossing during a point-to-point flight.
The third item misfiles the problem under §107.25 because the remote pilot is standing still. Standing still means you are not operating from a moving vehicle. The cars are still moving, and the people in them are still the subject of §107.145. Category 2 is not banned from every moving vehicle. A one-time transit that does not maintain sustained flight is the case the section allows. Practice the distinction on the free practice test. The course keeps §107.25 and §107.145 in separate lessons so the section numbers stay attached to the right facts.