Why don't driver's scale their loads?

If you're going to CA then set it where it needs to be and scale it. If it doesn't scale right get the load reworked. If the tandems are not at legal length then it isn't all great.

 

I worked in the scale business for a few years and am still a licensed scalemaster in four states.
I can tell you that highway scales are notoriously out of calibration.
I have appeared as an expert witness countless times on behalf of (mostly drivers) plaintiffs that challenge the tickets.
In all states, the burden of proof is on the citing officer. Of prime importance is proving the scale is within calibration limits, and in highway scales, they must be 'legal for trade', meaning they are accurate within 1/10th of 1% of their rated capacity.
Most highway scales are 200,000 pound capacity, so that means they are accurate within 200#.
I have yet to see one that at recalibration, is within or even close to those standards. And keep in mind I was doing scales back in the 80's.
Now in this era of budget cuts, it's rare for scales to be calibrated every three months. You're lucky if they're calibrated within one year!
If you scale your load on a certified scale (CAT scales are such) and receive an overweight ticked, simply rescale your load at the next scale down the road. If you show your weights at TWO scales coincide, most states won't even challenge you and simply dismiss the ticket by mail.
So to protect yourself, scale all your loads.

 

^^^ Thank you Emulsified. It's great to have expertise in a wide range of backgrounds on this forum to educate us.

 

Is there a standard or law on how often they have to be calibrated

 

All scales that are used to enforce local/govt codes and all scales used to determine monetary payment (as in fines or simple purchases) must be calibrated and sealed annually by the governing state board. Most states board is called something like "Dept of Weights and Measures" and usually are connected to the Agriculture department.
You will see a seal on the meter or scale head from the governing agency that is placed so no one can open it and fool with the calibration without breaking the seal.
That being said, in all cases, the person employing the scale for commerce (in this case the state) must prove the scale is calibrated and operating properly when a citation is written or if a person files a written complaint challenging the scale.
In highway scales, they do this by showing the date of the most recent calibration and subsequent (if any) calibration. If both show the scale operating properly (within tolerances), then it is unlikely you'll beat the ticket. They're proving the scale is working and it's assumed it's accurate between the two calibrations (when the citation was issued).
You are allowed to request the calibration and service records of that scale, either by written request (showing you have an interest in the proper operation of the scale) or by subpoena.
In the days of money, states usually calibrated scales every 90 days. These days, it's barely annually and sometimes not even that.
If a scale is out of calibration, every citation issued beyond the calibration date, until it's recalibrated, will normally be dismissed on written request.
Good attorneys will search the records of a scale and if they find this, will get your citation dismissed easily.
Now the practical part.
If you scale your load on a calibrated platform such as CAT scale (there are many more) and then receive a citation, scale again on a different scale and use these to show if your load is legal.
For instance, suppose you scale a load, show your drives at 33,900 and your tandems at 33960, but the highway scale shows drives at 35,200 and tandems at 33,100, then scale after the citation at another scale that shows your drives at 33,840 and tandems at 33,920 you have apparent proof that the highway scale is off.
You should request a copy of the calibration certs for both scales you've used as backup.
CAT calibrates their scales every 30 days and upon challenge from a service provider (the truck stop). They will actually do all the legwork for you if you've scaled on their scale JUST ONCE (previous to the ticket).
You present this to the court via letter, and most states will request dismissal rather than persue your fine.
The reason being, they know their scale is out of calibration and the judge, if he sees this is gross negligence (in his opinion) can summarily dismiss EVERY ticket issues on that scale since it's last calibration. This can be a lot of money and the state doesn't want a presidence where a lawyer, doing due diligence can find this and start contacting every person cited and getting their citations dismissed and fines paid, refunded.
The simple thing is to weigh your load. Most often, if you present a scale ticket to the scale house showing you scaled your load, they will send you on your way.
An immediate exception (that I know of) is Missouri. They have amongst the worst maintained scales in the country and will cite almost anyone, knowing most will pay the fine and go on their way.
I know this for a fact because I recently appeared as an expert witness in a case from the scale at Joplin on I-44. We found the scale was last calibrated more than 14 months previous! (subsequent calibration records showed it to be more than 7% out of calibration).
The lawyer that paid my fee and expenses is now contacting every driver that was cited on that scale.

 

Thanks again, emulsified, for your knowledge. I knew that having a certified scale ticket in hand was a necessary step for challenging any tickets issued by a LEO scale, but your advise to rescale the load on a certified scale after getting a ticket to have further documentation of your weights is invaluable. Interesting that the states would be putting themselves in a predicament where they would be losing revenue due to scales out of certified calibration.

 

You are my new hero

 

Spokane gave me an over weight warning once. Showed the dot cop my CAT scale ticket and he basicaly told me "too bad". It wasn't a ticket/fine but he still did the paperwork on it.

wish I had this info back then!

 

They're counting on our ignorance. Thankfully we have a forum with a bunch of great members to help us stay on top of things. I have learned tons just from hanging out here. Even before joining I lurked a lot and learned heaps before jumping in.