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Fixed Scales

Public information area for scale-house and fixed-scale topics.

What Fixed Scales Check For

Fixed scales — the permanent weigh stations built into highway shoulders and ports of entry — are where state enforcement personnel verify that a commercial motor vehicle's gross and axle weights are within legal limits and, at many locations, review driver and vehicle credentials at the same stop. Some states pair fixed scales with size and weight enforcement only; others integrate a Level III or higher roadside inspection into the same stop. Weight limits themselves are a mix of federal ceilings and state-specific rules, so the exact number that applies to a given route can vary.

How Federal Weight Limits Work

Limit How It's Set
Gross vehicle weight Federal law sets a maximum gross weight for vehicles operating on the Interstate System under 23 CFR 658.17; states may set their own limits, including higher limits under grandfather provisions, for non-Interstate roads.
Axle weight Individual axle and axle-group weights are capped by the Federal Bridge Gross Weight Formula, which limits weight based on the number and spacing of axles to protect bridges and pavement.
Oversize/overweight loads Loads that exceed standard limits require state-issued permits; requirements and routing restrictions are set individually by each state's DOT or permitting office.

Because weight limits combine a federal floor with state-specific permitting and grandfather rules, carriers running multi-state lanes should confirm limits for each state on the route rather than assuming a single national number applies everywhere.

Bypass Programs: PrePass, Drivewyze, and Weigh-in-Motion

Many fixed scales are equipped with weigh-in-motion (WIM) sensors embedded in the roadway that weigh a truck as it drives over them at highway speed, without requiring it to stop. Enrolled carriers running a transponder or app-based system such as PrePass or Drivewyze get screened against WIM data, safety history, and credential status in real time; trucks that clear the screening are signaled to bypass the scale, while trucks that don't clear — or aren't enrolled — are directed in for a full stop. Bypass enrollment doesn't exempt a carrier from weight or safety rules; it simply lets compliant trucks skip a physical stop when the system has enough data to clear them electronically.

Documentation Drivers Should Have at the Scale

A clean scale stop depends on paperwork being current and on hand, including a valid CDL, medical certificate, registration and IRP (apportioned registration) credentials, IFTA decal/license where required, any oversize/overweight or trip/fuel permits needed for the load and route, and — for loads near the limit — a recent, accurate scale ticket or weight documentation the driver can reference if a citation is contested.

Frequently Asked

Do I have to stop at every open weigh station?
In most states, yes — commercial vehicles are generally required to stop at open, marked weigh stations unless they're cleared through a bypass system like PrePass or Drivewyze, or a specific exemption posted at that location applies.
Does enrolling in a bypass program mean I'll never get pulled in for inspection?
No. Bypass systems screen based on weight, credentials, and safety data, but enforcement staff can still direct any vehicle — enrolled or not — into the scale for a closer look at their discretion.
What happens if a truck is found overweight?
Consequences vary by state and by how far over the limit the vehicle is — typically a citation and fine, and in some cases the load must be adjusted, transferred, or the vehicle held until it's brought into compliance before continuing.

Related Topics

Roadside Inspections Vehicle Maintenance DOT & MC Numbers Hours of Service

FHWA Truck Size & Weight program (ops.fhwa.dot.gov)

This page is general information, not legal advice. Weight limits, permitting requirements, and bypass program rules vary by state and route — confirm current requirements with the relevant state DOT or permitting office, and with FHWA's truck size and weight program, before planning a load.

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