What 390.21T(e) means in plain language
390.21T(e) is a marking or identification requirement tied to your truck or trailer. While this specific code has been cited only 1,898 times across our 13 million inspection records, it addresses vehicle communication standards that roadside inspectors check during compliance reviews.
The regulation focuses on how your vehicle displays required information or markings. Think of it as the inspector verifying that your truck or trailer carries the proper identification in the places where regulations say it must appear. This is an administrative citation—it's not a mechanical safety defect, and it's not about how you drive.
Because this is a "General/Admin" category violation, it carries a very low enforcement severity. Across our database, only 1 of 1,898 citations resulted in an out-of-service placement, reflecting the lower-risk nature of the code.
What our enforcement data actually shows
Our inspection records show that 390.21T(e) has been cited 1,898 times since we began tracking. In the last 12 months, we recorded zero citations for this code, and zero in the last 90 days. This suggests the violation is either becoming rare or is being detected less frequently at roadside.
The out-of-service rate for 390.21T(e) stands at 0.1%—meaning almost every driver cited gets to continue operating. Compare that to the all-FMCSR average OOS rate of 31.4%: this code ranks as one of the least likely to result in a vehicle being pulled from service. Nationally, 390.21T(e) ranks #544 out of 3,036 FMCSR codes by citation volume.
The rarity of recent citations suggests that either enforcement focus has shifted to higher-priority codes, or the industry has largely corrected this issue.
Who gets cited most
Across our 13 million inspections, the top carriers cited for 390.21T(e) include United Parcel Service Inc (USDOT 21800) with 8 citations, and Ryder Transportation Solutions LLC (USDOT 299073) with 7 citations. Our data shows fleets such as these with repeated citations, though the absolute numbers remain small relative to their fleet sizes and annual inspection exposure.
The top vehicle makes cited for this violation are Freightliner (155 citations), Freightliner variants (130 citations), and International trucks (90 citations). This pattern likely reflects that these makes represent a large share of the commercial truck population, rather than indicating inherent susceptibility to the violation.
How severe is this compared to similar codes
390.21T(e) sits in the General/Admin category alongside several peer codes. By comparison:
- 390.21TB2-DOT has been cited 74,663 times with a 0.0% OOS rate
- 390.21T(b) has 61,097 citations, also 0.0% OOS rate
- 390.21TB1-MC shows 59,189 citations with 0.0% OOS rate
Even among its low-risk peers, 390.21T(e) is substantially rarer. The sister codes in the 390.21T family and related marking requirements are cited far more often, yet all cluster around 0.0% to 0.1% OOS rates. This consistency suggests that marking and identification violations, as a category, are treated as correctable administrative deficiencies rather than safety emergencies.
How to avoid it
Since 390.21T(e) concerns vehicle marking or identification display, your prevention steps are straightforward:
- Before every trip, walk around your truck and trailer and verify that all required markings are visible, legible, and in the correct locations. Check for faded, missing, or obscured lettering or placards.
- Know what markings your carrier requires on your specific vehicle. Ask your dispatcher or safety manager if you are unsure; different carrier fleets may have different marking standards beyond the federal minimum.
- Check for weather or road damage that may have degraded markings. Mud, salt spray, or impact damage can obscure required information.
- If any marking is damaged or illegible, report it to maintenance before you operate the vehicle. Do not assume it will pass inspection as-is.
- Keep your USDOT number, MC number, and any hazmat placards clean and properly positioned. These are the most commonly inspected marking elements.
Because citation frequency for this code has dropped to zero in the last 12 months, the violation may be increasingly rare. Staying attentive to vehicle appearance and marking integrity during your pre-trip will keep you compliant.