Every commercial vehicle in the U.S. is subject to roadside weight enforcement and safety inspection. The two primary mechanisms are permanent weigh stations on interstate highways and roving DOT inspections conducted by certified state and federal inspectors.
Permanent weigh stations
Most major U.S. highways have weigh stations near state borders (and sometimes mid-state). Stations have a "Stations Open" / "Stations Closed" status displayed on highway signs and on apps like Drivewyze and PrePass. When open, all commercial vehicles meeting the threshold (typically 10,000 lb GVW or higher) must enter and submit to weighing. Failure to enter an open station is a federal violation.
What gets checked at the station
Vehicle weight (gross, axle, group); registration validity; IFTA/IRP cab card; current DOT inspection sticker; driver CDL and medical card; current Hours of Service status. If any item is questionable, the driver is directed to a secondary inspection area for a more thorough Level I, II, or III inspection.
Bypass services — PrePass and Drivewyze
Carriers can subscribe to PrePass or Drivewyze (typically $15 to $25/truck/month) to qualify for "bypass" privileges at participating weigh stations. Trucks with good safety scores are pre-screened electronically and given a "green light" to proceed without entering the scale. Bypass rates of 60% to 90% are common for well-rated carriers, saving each driver 20 to 60 minutes per week of weigh-station time.
Roving DOT inspections
Certified inspectors (state troopers, dedicated DOT enforcement officers) can conduct full inspections at any time on any commercial vehicle. The five inspection levels: Level I (full driver + vehicle, ~30 to 60 minutes); Level II (driver + walk-around vehicle, ~20 to 30 minutes); Level III (driver only, ~10 to 15 minutes); Level IV (special-purpose, e.g., cargo seal); Level V (vehicle only, no driver, 30 to 60 minutes); Level VI (radioactive shipments).
Out-of-service violations
An OOS violation immediately stops you from operating until the issue is corrected. Common driver OOS triggers: HOS violation (over 11 driving / 14 duty / 30-minute break), no current medical card, no current CDL, intoxication. Common vehicle OOS triggers: defective brakes, missing or defective lights, unsafe tires, leaking fluids, defective steering. OOS violations are reported to the FMCSA Pre-Employment Screening Program (PSP).
How to handle a routine inspection
Be polite and professional. Hand over requested documents promptly. Don't volunteer information beyond what's asked. Don't argue with the inspector — note any disputed findings and address them through your carrier's safety department afterward. Most inspections result in either no violations or minor paperwork corrections; clean inspections build your PSP score, which improves your future hireability.