Most roadside violations get read as checkbox items: a bad brake, a missing triangle, a log that does not match. A traffic control device violation looks simpler than it is. Code 392.2C is one of the entries I would not wave off, because it sits in the Unsafe Driving BASIC and stays on the carrier's record for a long time. The full record is on the 392.2C violation page.
What the code covers
49 CFR 392.2 requires every commercial motor vehicle to be operated in accordance with the laws, ordinances, and regulations of the jurisdiction where it is being driven. Code 392.2C is the specific entry inspectors use when the rule broken is a traffic control device: a stop sign, a signal, a lane-use sign, or a posted restriction at a ramp or bridge.
The violation is about the driver failing to obey the device. It is not about a sign being misplaced or a road being poorly marked. It also does not require a crash or an out-of-service order. A documented failure to obey the device is enough to write it.
Where it sits in the score
Here are the grounding numbers for this code:
- Description: failure to obey traffic control device
- BASIC: Unsafe Driving, violation group Dangerous Driving
- Severity weight: 5
- Used in SMS: yes
- Out-of-service indicator: no. The code does not take the vehicle out of service on its own.
- Recorded violations: 184,124, across 182,573 inspections
- Out-of-service instances: 18
That low out-of-service count is why people underrate this code. A 392.2C can end a roadside inspection with the driver back on the road, but the entry still feeds your SMS scoring at full severity.
How the weights work
The calculator constants explain why a single entry matters more than it looks.
- Time weight. An entry counts for 3 in its first 0 to 6 months, 2 from 6 to 12 months, 1 from 12 to 24 months, and 0 after 24 months. The influence drops in steps, not gradually.
- Severity cap. Severity contributions from one inspection to one BASIC are capped at 30. A bad stop with several violations cannot stack without limit inside that BASIC.
- Out-of-service bonus. The constant is 2, but Unsafe Driving is on the exempt list, so that bonus does not apply to this BASIC.
For a single 392.2C in its first six months, the raw contribution before any percentile normalization is severity 5 times time weight 3, which is 15 points. That number moves as the entry ages. The calculator shows how it shifts a BASIC once you add your other entries, which matters more than any one code in isolation.
What actually causes it
In my experience, these violations almost always come from approach and attention, not from a driver deciding to run a light. The common patterns:
- A late read of a signal. The driver sees the light change at the last moment and commits to the intersection instead of stopping.
- A rolling stop. The truck slows but does not come to a stop at a stop sign, often in rural areas where cross traffic seems absent.
- A missed lane-use sign. Construction zones and interchanges post sign sequences that a driver in the wrong lane cannot act on in time.
- A posted truck restriction. A weight, height, or route restriction at a bridge or ramp gets read after the turn has been committed.
Controls that work are mostly planning controls. Check posted truck restrictions during route planning, not at the ramp. Set up for signals early enough to stop without hard braking. Make a full stop at stop signs, check both directions, then proceed. Review any camera or GPS alerts for these events, because they tend to repeat on the same routes.
Key takeaways
- 392.2C is scored under Unsafe Driving at severity weight 5, even though it is not out-of-service on its own.
- Time weight drops in steps: 3, then 2, then 1, then 0 after 24 months.
- Severity contributions are capped at 30 per inspection per BASIC.
- Most entries trace back to approach planning and attention at intersections, stop signs, lane signs, and restricted routes.
If you want to see how a single entry like this moves your own numbers, start with the calculator. Terms such as BASIC and time weight are defined in the glossary.