This is a great question we get a lot, in many variations. Are your plans DOT approved? Are the plans Stamped? We think it’s great to know the level of plans you get when you buy, so asking about certified plans is a great place to start. However, this question means different things to different people.
Let’s look at the details. Hopefully, we’ll touch on your version of the question.
What Are Certified Plans?
Let’s start with the basics. “Certified” often references an application with something to review by an authority for adherence to specific rules or requirements. Examples are UL approvals or CE certification.
Most electric devises have a CE or UL mark signifying it meets certain levels of electrical safety. We assist with this for some customers at Synthesis. By submitting the product and documentation for review, they can test it for compliance. Certification comes after a review of the design AND a prototype of the product.
Something similar happens with Trailers. In most jurisdictions, certification comes after construction – by inspecting the trailer for road worthiness and adherence to local laws (axles, tires, lighting, wiring, chains, etc.). They inspect the actual trailer, and look at the material, the welds, the components, and all the details.
Some things matter for safety (like the frame, axles, lights), and some things don’t matter (like the paint you choose). The trailer is “Certified For Highway Use” by the inspector, and usually they don’t look at the plans.
So, to get Certified, or DOT approved, or DMV licensed, it’s the actual physical trailer that matters, not the plans.
Is The Process Silly?
Some say it’s a ridiculous process, because plans should be part of certification. After all, you should know what the trailer is designed for, right? While I agree, the truth is people make poor choices. You can put 5000 lbs on a 3000 lb trailer if you want. It might break, but there is nothing to stop you. Same for switching to weaker, cheaper material during the build. Certified plans don’t help these, and inspection won’t take that responsibility.
When you pull a trailer, it is your responsibility. Inspection just says the trailer meets minimal legal needs like lights, brakes, chains, etc.. While they do look at construction — presumably to help avoid harm or injury to others, they can’t inspect true strength, or weld integrity, or test the alloy, or certify stability.
So what good is certification? I’ve asked that too. Yet, it just is, so we jump through the hoops. All of this gives good reason to get trailer plans from an authoritative source, then build with integrity.
Fully Engineered Plans
In asking about Certified Plans or DOT Approved plans, some people are really asking about the engineering. Do the plans include engineering? Or are they just a pretty picture? Did someone actually do the analysis?
That is a fair question, because there are plans out there for sale from the guy in a shop that just learned CAD. I say that tongue-in-cheek, but it’s worth knowing the skill level of the person who made the plans. It does not mean their plans are bad, I don’t pretend to judge others. However, it might mean they did not do proper analysis. It might mean they built a trailer and it works for them, so they decided to sell the plans.
We have Fully Engineered Plans from our parent company Synthesis Engineering. Products made from these plans will perform as stated – when built as defined, with proper materials, skill, and care in construction. We do the full engineering. We do it in house where we have control of the design so we can tweak it and make sure it’s right before we show it to you. With our plans, if you build it well, it will perform as stated.
However, if you abuse or misuse the trailer – overload it, hit a tree, etc. – that’s different. Of course, our designs are robust to handle the inevitable minor oops. Performance assumes care and common sense. The Bottom Line: Because materials, component choices, options, customizing, and your building skill are outside of our control, advance certification is not possible.
So, Are Your Plans Engineered? Yes, complete.
This is ALSO true of all our plans, like Shop Tools Plans for Cranes, Presses . . . . Everything. That’s how we roll.
Do Your Plans Have An Engineering Stamp?
When considering Certified Plans, some people are really asking about a ‘stamp’ of some sort from an engineer. Yes, there are engineers that wield a stamp, but again if we look at the actual process, it is sort of meaningless because the real inspection happens after building the trailer.
One company claims they are the only one with engineered plans. It’s a little sad that they choose deceit in their advertising, but whatever. They also sell the same plans on several websites making it look like they are different companies. Beware. Yes, their plans include a stamp, from a long time ago. (The engineer who did them retired years ago.) I think he did a good job for the time, but if you’ve ever read his plans, they can be confusing, and they are not complete.
All our plans have full engineering as mentioned above. Our design process includes extensive engineering using tools like FEA that were not available years ago. With new technology comes better tools for a more thorough analysis. For us, even our original plans from years ago have improved with a revisit in newer engineering tools.
In addition, through Synthesis, we do engineering for trailers and plans sold by other companies — not just our own plans. Check out Johnson Trailer Parts. I mention this because fully engineered plans are available from more than just the one company. We know, because we did them, like this Dump Trailer.
So, Do Your Plans have an Engineering Stamp? No, it is not really pertinent.
Are Your Plans DOT Approved?
For certified plans, some people are really asking about a DOT Approval. There is not a DOT approval for DIY plans. While that would be nice, again, the real certification comes after building. Local laws differ, but usually the trailer inspection is by a local authority. Perhaps at a police station, or the DMV. Most places require an inspection, then they give you a VIN (Vehicle Identification Number) so you can license it. The DMV takes the inspection or VIN as the approval.
Rightfully so, the inspection looks at the actual trailer. How you build it, your skill, your welding, your choices of material, components, etc.. This is where the rubber meets the road, so to speak. We support inspections as there are people who lack common sense or concern for others — see our Rattle Traps on the Road Article.
In a good inspection, they will look at materials, welds, and verify component load ratings (axles, tires, coupler, chains, etc.). They will look for adherence to local laws (lighting, wiring, brakes, chains, etc.). An inspector may ask to see plans, but usually not. They inspect the trailer, not the plans. That said, feel free to show them the plans!
In my experience, most inspections are not super thorough. If the trailer looks nice, the welds look good, bolts are tight with lock nuts, and it appears well built, they may focus on the lights, brakes and other legal requirements. In all the trailers I’ve built, I’ve only had one thoroughly inspected — and it passed just fine.
So, Are the Plans DOT Approved? Actually, the right question: Will your work be DOT Approved? Do a good job building, then you’ll pass the inspection and get the approval.
Certified Plans Summary
In summary, our plans do not have a DOT Approval, DMV licensing guarantee, or other government certification, because your build quality, and your choices are all factors. The inspection, for most jurisdictions, is the point of certification. Build the trailer well, and you won’t have trouble with inspection.
In comparing our plans to others, certified or approved is not really the point. I don’t know of any plans out there that are fundamentally weak or anything like that. Not that I test them, but from what I see, the weakest trailers are from the big retailers. (See the article about a Bent Tongue on a Weak Trailer.) Yet, I believe the quality of our plans is superior because we provide more options, better detail, and good explanations in the instructions. They are fully engineered plans, because that matters, even if there is not a special reason for pre-certified plans.
For your trailer, I personally recommend starting with the trailer plans that suits your needs best, even if it is from a competitor. Build it to the best of your ability. We have many trailer plans, but not everything, so look around. When you’re ready to buy plans, if we have one you want, we’re confident our plans will give a great road map for building your awesome trailer.
DOT Approved — Inspection Advise
Getting the trailer Certified for use, (or DOT approved, or whatever you want to call it) can be a little nerve-racking. No one likes having an authority scrutinize their work. Anyway, here are some helpful tips to make the process go smoothly.
- Build it well. Not only for inspection, but for you, so the trailer will serve you a long time.
- Clean up your welds. If an inspector senses short-cuts, they will look much closer. Things that might not matter — like cleaning up the welds — can trigger the reaction. That’s just human nature.
- Test everything yourself prior to arriving for inspection. Check the lights, signals, brakes, etc.. Make sure it all works flawlessly. If you’re confident, then it will show.
- Anchor all the wires. If the wires are dangling, they will look at things much closer. Anchor them up nice and neat, so it shows that you know what you’re doing. Then, silliest one to me, paint before wiring. Like in #2 above, things that look like laziness (painting over the wires) will get bad attention.
- For tiny houses, we recommend doing the trailer inspection and licensing before you build the house on it.
- Take the plans with you in case the inspector wants to see them, but note the above about Certified Plans. They are fully engineered, and that’s what matters.
The point of all of this: It’s not really a game, but we have to treat it a little like that. You can’t control if the inspector spilled his coffee in the morning. Sometimes they are just in a bad mood, or on an ego trip, so don’t give them something to trigger a conflict. Your objective is to get in, pass inspection, then be on your way.
Good luck with your trailer build !! Good luck with your trailer inspection, and your DMV licensing.