The Secret Life of Cat Scales. How Truckers Weigh Their Loads at the Truck Stop


A CAT scale is a specialized heavy-duty scale designed specifically to weigh semi trucks and trailers. CAT stands for “Certified Automotive Transport.” CAT scales are located at truck stops, travel centers, and freight facilities and are necessary to ensure trucks are not overweight and in compliance with federal and state weight laws. Using a CAT scale is a crucial part of a truck driver’s job.

The purpose of using a CAT scale is to obtain accurate axle weight and gross vehicle weight measurements to make sure the truck is within legal weight limits before proceeding. The process involves carefully positioning the truck on the scale platform, reading the digital weight readings from inside the truck once the weights stabilize, and getting a printed weight ticket. The weigh ticket will show individual axle weights and the total gross vehicle weight.

This section will provide an overview of the full process for truck drivers to properly weigh their truck and trailer on a CAT scale. Key steps covered include locating scales, preparing for weighing, going through the weighing process, reading and analyzing the weigh ticket, understanding legal weight limits, procedures for reweighing, paying for the weight ticket, and CAT scale maintenance.

Locating a CAT Scale

CAT scales can be found at many truck stops across the United States. Major chains like Love’s, Pilot, and TA offer CAT scales on-site at certain locations. You can often easily spot the scale area while driving through the truck stop. Additionally, there are over 1,500 independently-owned CAT scale locations. These independent sites only offer the weighing service and are not attached to a larger truck stop.

The easiest way to find CAT scales along your route is to use trucker apps like Trucker Path or Big Rig Travels. These apps show weigh station locations and can also pinpoint CAT scales at truck stops or standalone sites. You can plan where to weigh your rig based on upcoming weigh stations, DOT inspection sites, or weigh-sensitive delivery locations. Planning your weighing stops rather than randomly looking for a scale will save time and fuel. Some drivers also use Google Maps and filtering for keywords like “CAT scale” or “truck scale.” However, trucker apps provide the most targeted and up-to-date information.

Preparing for Weighing

Before pulling onto the scale, take some time to prepare so the weighing process goes smoothly. Make sure you have the necessary items and properly line up your truck and trailer.

Materials Needed:

  • Scale ticket – You’ll receive a printed weigh ticket.
  • Driver’s license/ID – Some scales require ID to match the driver to the truck.
  • Payment – Most CAT scales accept credit cards and cash. Some have RFID cards for easy weighing and payment.

Parking: recommends lining up so your front steer axle is on the first platform. Pull forward slowly and make sure your entire truck and trailer are fully on the scale. Park and put your vehicle in neutral.

Weighing Process

The actual process of weighing your truck at a CAT scale is straightforward. Here are the main steps:

First, drive your truck slowly onto the scale platform. Make sure your entire truck is fully on the scale pad. It’s important that no wheels are hanging off the edge of the scale. Position your truck straight on the platform and come to a complete stop once you are fully on the scale (source).

Next, wait patiently in your truck while the scale calculates the weight. The process is automated and usually takes just a few seconds. Don’t move the truck during this time as it can impact the accuracy of the reading.

Finally, when the weighing is complete, you’ll get a printed weigh ticket ejected from the machine near the scale. Take the weigh ticket, making sure to get all pages if it’s a multi-page printout. The weigh ticket will show the individual and total weights for your truck including the steer axle, drive axles, trailer axles, and gross vehicle weight (source).

Reading the Weigh Ticket

Understanding the various weight readings on your weigh ticket is crucial for remaining legally loaded as well as maximizing your payload. The three key weights are:

Gross Weight

This is the total weight of the truck and trailer including cargo. The gross weight must stay under the legal limit determined by things like number of axles and local regulations.

Net Weight

The net weight is the weight of just the cargo being hauled, excluding the weight of the empty truck and trailer. Knowing the net weight helps determine your payload and profitability.

Tare Weight

The tare weight is the weight of the empty truck and trailer without any cargo loaded. Subtracting the tare weight from the gross weight gives you the net weight of the cargo.

Carefully reviewing these weight figures on your weigh ticket can help you maximize your legal load while avoiding overweight fines and other issues.

Legal Weight Limits

Federal regulations set by the Federal Highway Administration and most states establish maximum allowable weight limits for commercial motor vehicles traveling on public highways. The most commonly applied limits are:

  • Single axle: The maximum load on one axle must not exceed 20,000 lbs.
  • Tandem axle group: The maximum load on a tandem (2 consecutive axles spaced 40 inches or less apart) must not exceed 34,000 lbs.
  • Gross vehicle weight: The maximum operating weight, including the truck, trailer, and cargo load, must not exceed 80,000 lbs.
  • Bridge formula: This calculates maximum axle weights based on axle spacing.

To avoid costly citations for overweight vehicles, truck drivers must carefully comply with all legal limits. CAT scales provide certified weigh tickets to document compliance.

Re-Weighing Procedure

Sometimes when a driver weighs their truck, they may find their weight is over the legal limit. If a driver is overweight, they will need to re-weigh their vehicle after adjusting their load to bring it into compliance. There are a few things to keep in mind about the re-weighing procedure:

When re-weighing is needed:

  • Re-weighing is required if a truck is overloaded according to the weigh ticket from the initial weighing.
  • Drivers should adjust their load by removing cargo until they are within legal weight limits. This may require shifting cargo or offloading it.
  • CAT scale operators will allow one free re-weigh within a reasonable timeframe after the original weigh to verify the vehicle is now legal.

Getting a new weigh ticket:

  • After adjusting the load, the driver simply pulls back onto the scale for another weighing.
  • The operator will produce a new weigh ticket, which should show the vehicle is within prescribed weight limits.
  • It’s recommended drivers get the new weigh ticket time stamped to demonstrate compliance if questioned.

Understanding the procedures for re-weighing overloads is important for both CAT scale operators and truck drivers to ensure safety and compliance with weight regulations.

Paying for the weighing service is an important part of the overall CAT scale process. There are several options truck drivers have for paying the weighing fee.

Paying for Weighing

The typical fee for using a CAT scale is around $10-15 for the first weigh and $3-5 for additional weighs (Weigh My Truck – CAT Scale). Drivers have a few options for paying this fee:

Cash – Most CAT scales accept cash payments. The scale will provide change as needed after the weigh.

Credit Card – Many CAT scales now allow payment by major credit cards. This provides a convenient option for drivers who don’t have sufficient cash on hand.

Fleet Cards – For drivers of commercial fleets, many CAT scales accept payment using fleet fuel or payment cards. This allows easy billing directly to the fleet company.

Weigh My Truck App – The Weigh My Truck app by CAT Scale allows drivers to pay for weighing through the app using credit card, ACH payment or fleet billing options (ACH Payment Option Added to Weigh My TruckTM App). This speeds up the weighing process.

Having flexible payment options allows truck drivers to easily take care of the weighing fee and focus on meeting federal weight guidelines and staying safe on the road.

CAT Scale Maintenance

Proper maintenance and calibration are crucial to ensure CAT scales provide accurate weight readings. According to Michelli, scales should be calibrated every 6-12 months depending on usage volume and weather conditions ( The calibration process involves a technician using test weights to check the scale’s accuracy and make any necessary adjustments.

Regular maintenance also helps identify potential issues before they cause inaccurate readings. This can include inspecting foundations, load cells, and wiring connections. Buildup of debris, damage from weather or chemical exposure, and loose hardware can all impact accuracy if not addressed. Preventative maintenance checks and recalibration ensures that CAT scales continue to provide truckers with reliable weights.


Properly weighing your truck is an important process that all truck drivers should follow closely in order to remain legal and safe on the roads. Using a certified CAT scale properly ensures your truck is within the legal weight limits for the states you’ll be travelling through. Taking the time to weigh and re-weigh as needed protects you, other drivers, and the roads from the risks of overweight trucks. While it adds some time to your route, legal and accurate weights are essential for every haul.

The weighing process may seem simple on the surface, but following the proper procedures at the right times is key. Locating CAT scales along your route, carefully driving up onto the scale, reviewing your weigh ticket, and re-weighing if necessary are all critical steps. While paying to weigh your truck is an added expense, the fines and risks of overweight loads make it well worth the small investment. Remember to treat CAT scale equipment and personnel with professionalism.

By learning the ins and outs of utilizing truck scales, truck drivers can help promote safety and compliance across the industry. The process improves your own skills as well. Mastering CAT scale weighing demonstrates you are a responsible, safety-minded operator who follows best practices on every haul.

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