What 393.201(e) means in plain language
This regulation prohibits drilling holes into the flange of your truck's frame rail. The frame rail is a critical structural component that runs along the length of your vehicle, and the flange is the horizontal lip or edge that provides strength and rigidity. Drilling holes into this area weakens the structural integrity of the frame and compromises the vehicle's ability to safely handle loads and impacts.
Inspectors cite this violation when they discover holes that have been intentionally drilled into the frame rail flange—typically from aftermarket modifications, custom welding work, or attachment points added without proper engineering. Even if the holes seem small or harmless, any drilling into the flange itself is a violation. The regulation exists because frame integrity is fundamental to braking performance, load stability, and crash safety.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.201(e) is one of the least-cited vehicle maintenance violations. Our database shows only 20 citations for prohibited holes in frame rail flanges all-time, with zero citations in both the last 12 months and the last 90 days. This code ranks #1938 of 3,036 FMCSR codes by citation volume—meaning it's extremely rare in roadside enforcement.
When cited, this violation results in an out-of-service order only 5.0% of the time (1 out of 20 inspections). That's significantly lower than the all-FMCSR average OOS rate of 31.4%, indicating that inspectors view most frame rail flange holes as correctable defects rather than immediate safety hazards that require the vehicle to be pulled from service on the spot.
The fact that you've received this citation means you're in a very small group. The rarity of enforcement on this code does not mean it's ignored—it means most drivers maintain frame integrity and avoid custom modifications that compromise it.
Who gets cited most
Our inspection records do not include state-level breakdowns in the data available for this code, so we cannot name specific states where citations cluster. However, our data does show that Loras Trucking Inc and Super Logistics LLC each received 2 citations for this violation, while several other carriers had single citations. This reflects that frame rail flange issues are scattered across the industry rather than concentrated in particular fleet operations or regions.
The vehicle makes cited most often for this violation were Freightliner (3 citations), Fontaine trailers (3 citations), and Wabash trailers (3 citations), followed by MCI (2 citations). This spread across different manufacturers suggests the violation is not tied to any particular truck or trailer model but rather to how individual vehicles have been modified.
How severe is this compared to similar codes
To understand where 393.201(e) sits in the enforcement landscape, compare it to other vehicle maintenance codes in the same category. Inoperable required lamps (393.9(a)) has been cited 660,737 times with a 15.4% OOS rate—meaning lamps are cited thousands of times more often but are removed from service less frequently than the all-FMCSR average. General inspection/repair/maintenance violations (396.3(a)(1)) total 236,919 citations with a 45.3% OOS rate—cited much more often and causing out-of-service orders far more frequently.
Internally defective slack adjusters (393.47E) and windshield condition defects (393.78) are also more commonly cited (180,363 and 157,894 citations respectively) but carry lower or comparable OOS rates. The key difference is citation volume: frame rail flange holes are detected so infrequently that they don't represent a systemic enforcement priority, even though the underlying safety concern—frame structural integrity—is genuine.
How to avoid it
The simplest way to avoid a 393.201(e) citation is to never drill into your frame rail flange yourself and to review any custom work performed on your truck before accepting it back:
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Inspect your frame rails during every pre-trip inspection. Look along both sides of the frame for any holes, particularly near the flange (the horizontal lip on top of the main rail). If you find holes that weren't there before, report them to your fleet maintenance team immediately.
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Do not authorize custom attachment points without consulting your fleet's engineering or maintenance department. Many drivers request modifications to mount equipment (toolboxes, auxiliary fuel tanks, or third-party devices) without realizing the installation requires drilling. Always route these requests through proper channels.
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If your truck has been in an accident or major repair, inspect the frame rails carefully when you get it back. Welding or fabrication work can sometimes include holes that violate this regulation. Verify that any structural repairs meet DOT specifications.
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Beware of aftermarket parts suppliers who drill attachment holes directly into the flange. If you're adding equipment, specify that mounting points must not compromise the frame rail itself. Use approved auxiliary frame components or welded mounts designed for that purpose.
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If you drive an older truck or recently acquired one, walk the frame during a full visual inspection. Previous owners or fleet operators may have made modifications you're unaware of. Identifying and removing illegal holes before roadside inspection protects you and your carrier from citations.
Frame rail integrity is foundational to vehicle safety. Keeping holes out of your frame flanges is straightforward—avoid unauthorized drilling and inspect what's there before it becomes a roadside surprise.