The first few trips through a weigh station can feel intimidating. Preparation means knowing your load, keeping credentials and logs current, and following the instructions given to your truck.
What weigh stations do
Commercial-vehicle facilities check more than total weight. They can screen vehicle credentials and identify trucks needing further inspection. ADOT's screening guidance describes checks for weight, registration, permits, and out-of-service orders at Arizona ports of entry.
When to enter and when to bypass
Follow roadside signs, officer directions, and authorized bypass instructions applicable to your vehicle. Arizona uses electronic screening that can direct a truck to enter a port or continue past it. An open facility does not mean every truck will stop on its static scale, and a bypass at one station does not authorize bypassing another.
If directed in, obey the posted approach speed and designated lane. Watch the scale's signs and signals for where to position the truck and whether to stop or keep moving. Do not assume every facility uses the same sequence.
Under 80,000 pounds does not automatically mean legal
FHWA's Interstate weight guidance gives these basic federal limits:
| Weight | Basic Interstate limit |
|---|---|
| Gross vehicle weight | 80,000 lb |
| Single axle | 20,000 lb |
| Tandem axle | 34,000 lb |
The Bridge Formula also limits weight on groups of axles according to their number and spacing. Exceptions, permits, and route restrictions can change what applies. A 78,000-pound combination can still have an overloaded axle group. Check the load's weight distribution and applicable route limits before reaching an enforcement scale.
Common inspection levels
Being weighed does not necessarily mean a full vehicle inspection. If selected, follow the inspector's instructions. CVSA defines the inspection levels, including:
- Level I: driver requirements and vehicle safety components, including brakes, steering, tires, lighting, coupling, and cargo securement where applicable.
- Level II: a driver and vehicle walk-around covering items that can be inspected without physically getting underneath the vehicle.
- Level III: driver, credential, and administrative requirements, without the Level I or II mechanical examination.
There is no appearance-based guarantee against inspection. Keep the truck compliant before each trip.
Have records and ELD information ready
Know where to find your CDL, registration, applicable permits, shipping documents, and other credentials required for your operation. If you use an ELD, know how to display and transfer the records requested by an inspector. Follow carrier procedures and the ELD's instructions.
Medical qualification needs particular attention. For Arizona non-excepted interstate CDL/CLP holders, medical results are transmitted electronically. Verify your status through AZ MVD Now and resolve discrepancies with the medical examiner and MVD. Arizona non-excepted intrastate holders still have paper-submission requirements; see the medical-certification section of the Arizona CDL manual.
The nationwide temporary paper-MEC transition relief ended October 11, 2026. From October 12, the renewed FMCSA exemption applies only to Alaska-issued CDL/CLP holders and their employers, for up to 60 days after certificate issuance. Arizona drivers cannot rely on that exemption to substitute a paper certificate for the required electronic medical status. Follow current requirements for your operation and any applicable medical variance documents.
If an inspector finds a violation
Remain professional, provide requested records, and notify your carrier of the inspection report. Ask for clarification if you do not understand an instruction.
Not every violation results in an out-of-service order. If the vehicle is declared out of service, federal rules prohibit operating it until the repairs required by the notice are completed. A driver can separately be prohibited from driving for an Hours-of-Service or qualification problem. Follow the order's specific requirements; a generic ten-hour rest is not a remedy for every violation.
Before the trip, address unsafe equipment, verify the load, check credentials, and keep duty records accurate. Compliance starts before the weigh-station sign.
