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Field notes

Twelve questions to ask before you sign

Every product in this category demonstrates well, because every demonstration is built on a load that works. These twelve questions are the ones that separate the products by what they do on the load that does not.

  • Twelve questions
  • A number behind each one
  • What a straight answer sounds like

How to use this

Ask them on your own load, not on theirs

The single most useful thing you can do in an evaluation is bring a load of your own that went wrong, and ask the product to explain it.

Take a real load from the last year that came back from the scale differently from how it was planned, or that got a citation, or that had to be rebuilt on the dock. Bring the equipment geometry, the freight list and the scale ticket. Ask every vendor to reproduce it.

A product that can reconstruct what happened, and name the group that bound and by how much, has told you more in ten minutes than a quarter of reference calls. A product that cannot has also told you something.

The twelve questions below each come with the arithmetic that makes them matter, so that when an answer sounds reasonable you have a number to check it against.

Bring a load of your own that went wrong, and ask the product to explain it. A vendor who cannot has also told you something.

One to four

The road and the run

Whether the truck can physically and legally get there, and whether the day it is planned into is a day a driver can lawfully work.

Question 01

Is the road planned around my actual combination, or a generic truck profile?

Why it matters

Truck navigation products differ enormously here. Some carry a full set of vehicle attributes — height, width, length, gross weight, axle count, hazmat class — and route around restrictions that apply to those attributes. Others carry a coarse vehicle class, which means a 13 ft 6 in trailer is planned the same way as an 11 ft box truck.

The number behind it

The arithmetic behind question 1.
Trailer height13 ft 6 in
Clearance on the shortest road12 ft 4 in
What a generic profile returnsa road the trailer does not fit under

What a straight answer sounds like

A straight answer names the attributes the network carries and shows you where they come from on your own equipment record. A vague answer talks about truck routing without saying which attributes it uses, which usually means height and weight but not much else.

Question 02

What happens when no fully compliant road exists?

Why it matters

Every routing service eventually meets a request it cannot satisfy: a combination too tall, too heavy or too long for anything in the area. What happens next is the most important behaviour in the product, and it is almost never in the brochure.

The number behind it

The arithmetic behind question 2.
Behaviour Areturns the best road found, silently
Behaviour Breturns the road and names the restriction it relaxed
Cost of behaviour Aa trailer meeting a low bridge at speed

What a straight answer sounds like

A straight answer describes the exact signal you get back and what it contains. Ask to see it on a deliberately impossible request during the demonstration, not described in a slide.

Question 03

Is the fourteen-hour duty window modelled as pausable?

Why it matters

The US duty window runs on the wall clock from the moment the driver comes on duty, and nothing stops it. Planning tools that treat it as a clock that pauses during breaks and detention produce plans that look fine and that a logging device will refuse.

The number behind it

The arithmetic behind question 3.
Driving allowed in a day11 h
Duty window14 h, running regardless
After three hours of detention10 h 30 min of driving is all that fits

What a straight answer sounds like

A straight answer states the three numbers back to you — 11 hours, 14 hours, 30 minutes after 8 — and can show a plan where detention reduces the achievable driving time. If the demonstration always shows a clean day, ask for a dirty one.

Question 04

Is compliance re-solved for every leg of a multi-stop run?

Why it matters

A milk run is a different load on every leg. Freight boards, freight comes off, and the axle weights change at every stop. A verdict computed once at the origin describes the leg with the least freight aboard, which is frequently the only leg that was never in danger.

The number behind it

The arithmetic behind question 4.
Leg one, 36,000 lb aboarddrive tandem 28,395 lb
8,000 lb boards at stop two, near the nosecentre of gravity moves forward
Leg two, same truckdrive tandem 34,175 lb, over the limit

What a straight answer sounds like

A straight answer shows you a verdict per leg, with the freight manifest for that leg beside it. Anything that gives one verdict for a five-stop run has not answered the question.

Every demonstration is built on a load that works. Ask to see one that does not.

Five to eight

The weight

Four questions that separate a tool which adds weights up from a tool which works out where the weight sits.

Question 05

Do you compute per-axle weight from where the freight sits, or take a gross weight as an input?

Why it matters

This is the dividing line in the whole category. A product that accepts a gross weight can check gross limits and nothing else. A product that takes item weights and positions can solve the statics and tell you the five numbers that actually get enforced.

The number behind it

The arithmetic behind question 5.
Gross weight76,000 lb, legal
Drive tandem, solved33,920 lb
Margin nobody could see from the gross80 lb

What a straight answer sounds like

A straight answer describes the inputs: item weight, position along the deck, lateral offset, and the geometry of the tractor and trailer. If the only weight field in the product is a single total, the answer is no, however it is phrased.

Question 06

Do you evaluate every consecutive axle subset, and can I see the worksheet?

Why it matters

The Federal Bridge Gross Weight Formula applies to every group of two or more consecutive axles. On a five-axle combination that is ten groups, and the seven interior ones are where it usually bites. A verdict without a worksheet cannot be checked, by you or by anyone in a dispute.

The number behind it

The arithmetic behind question 6.
Subsets on a five-axle unit10
Subsets most checks cover3
Interior four-axle group at 38 ft67,500 lb limit, and it is often the binding one

What a straight answer sounds like

A straight answer shows a table with one row per subset: spacing, axle count, formula result, applied limit, actual load and margin. Ask to see it for a load that fails. A red banner is not a worksheet.

Question 07

How do you handle the rounding and the two caps?

Why it matters

The formula result is rounded to the nearest 500 lb, capped at 80,000 lb, and capped again at 34,000 lb for a pair spaced 8 ft or less. Each of those is a place where implementations go wrong, and each error is worth hundreds or thousands of pounds.

The number behind it

The arithmetic behind question 7.
Two axles at 8 ft, formula result38,000 lb
Correct limit after the tandem cap34,000 lb
Four axles at 50 ft, correctly rounded75,500 lb, not 75,000 lb

What a straight answer sounds like

A straight answer gives you those numbers on the spot, because anyone who has implemented it correctly has met all three cases in testing. Hesitation here is informative.

Question 08

Do you carry the tire rating and the manufacturer's axle rating, or only the statute?

Why it matters

Three separate ceilings apply to every axle group and the lowest one binds. Tools that carry the statutory table alone will call a load legal that the tires it is sitting on are not entitled to carry.

The number behind it

The arithmetic behind question 8.
Statutory steer axle limit12,000 lb
Two steer tires at 8.5 in of tread, 600 lb per inch10,200 lb
The limit that actually applies10,200 lb, well below the statute

What a straight answer sounds like

A straight answer shows a per-axle record with tire count, tread width and rating on it, and a verdict that names which of the three limits bound. If the equipment model has no field for a tire, the answer is no.

The number behind six of the twelve questions

lb
  • Question 4 · freight boarding at stop two5,780 lb

    added to the drive tandem on a leg nobody re-solved

  • Question 7 · the tandem cap left off a pair at 8 ft4,000 lb

    capacity granted that does not exist

  • Question 8 · the statute against the tire rating1,800 lb

    what the statute allows and the tires do not

  • Question 10 · fuel taken on after the plan240 lb

    onto the drive tandem, with no freight moved

  • Question 6 · the interior four-axle bridge group200 lb

    over, on a group that has no name in a yard

  • Question 5 · margin the gross figure cannot show80 lb

    all that is left on the drive tandem at 76,000 lb gross

The same figures printed beside the questions above, put next to each other on one reference combination. The smallest of them is the one that matters most: 80 lb is the entire margin left on the drive tandem, and no gross weight in the world will show it to you.

Nine to twelve

The answer, and what happens to it afterwards

Four questions about what the tool hands back, whether it stays true through the day, and whether it will still mean something in two years.

Question 09

Which jurisdictions do you carry, and what happens when one changes a limit?

Why it matters

Weight limits are not national and they change. If the limit table is compiled into the product, a state legislature's amendment becomes a software release and you run on the old number until it ships.

The number behind it

The arithmetic behind question 9.
Limits carried as codea rule change is a release
Limits carried as dataa rule change is a form
What you need to askhow long between a published change and a correct verdict

What a straight answer sounds like

A straight answer names the jurisdictions covered, states who maintains them, and gives you a time from publication to effect. The best answer lets you enter an override yourself when your own reading of a rule differs.

Question 10

Is fuel burn modelled, and can it change the verdict?

Why it matters

Diesel is weight and it sits on the tractor near the middle of the wheelbase, so it loads the steer axle and the drive tandem roughly evenly. A load solved at the desk and then fuelled is a different load, and a load four hundred miles later is different again.

The number behind it

The arithmetic behind question 10.
Drive tandem as planned33,920 lb
After about 68 gallons of fuel, 480 lb34,160 lb
Resultlegal at the desk, over at the scale, with no freight moved

What a straight answer sounds like

A straight answer shows the verdict recomputed at departure, at the midpoint and at arrival, with the fuel state at each. If fuel appears only as a cost, it is not in the physics.

Question 11

When a load fails, do I get a correction or a verdict?

Why it matters

A red banner saying a load is illegal tells the person holding the forklift nothing they can act on. The useful output is the specific move, in the units the yard works in: holes on the tandem, notches on the fifth wheel, feet along the deck.

The number behind it

The arithmetic behind question 11.
Output AOVERWEIGHT
Output Bdrive tandem over by 175 lb, move the trailer tandem back three holes
Difference in practicea phone call to a planner, or a two-minute job

What a straight answer sounds like

A straight answer demonstrates the correction on a failing load during the demonstration. Ask what happens when no position works: the honest products route that case to a permit instead of asking for something impossible.

Question 12

What does the record look like two years from now?

Why it matters

A compliance decision is only worth what you can prove about it later. The question in a dispute is never what the system says today. It is what it said then, who changed it, and what the numbers were before they touched it.

The number behind it

The arithmetic behind question 12.
Loggedthat a change happened
Neededthe full state before and after, and who made it
What settles a disputea record, not a recollection

What a straight answer sounds like

A straight answer shows you an audit entry with the previous and the new state side by side, and can reconstruct a load as it stood on a given date. Ask specifically what happens to the trail when a load is deleted.

Three more

The questions that are not about the software

Products get chosen on capability and abandoned on everything else.

What does it cost when we use it the way we actually work?

Planners open a load, look at it, adjust it and open it again. If the pricing model charges for that, the tool acquires a meter and people stop using it properly, which is a slower and more expensive failure than not buying it. Ask specifically what re-opening an existing plan costs, and whether there is a ceiling you can set in advance rather than an alert you receive afterwards.

Who can change a limit, and how do we know they did?

An axle limit is a legal position, not a preference. Ask which roles can edit a rule set, whether that is enforced on the server or only hidden in the interface, and what the record of the change looks like. Hiding a button is not access control.

What is finished, and what is on the roadmap?

Every product in this category has edges. The ones worth working with will tell you where theirs are without being pushed. A vendor who says their tool models B-trains, doubles, self-steering multi-axle trailers, every state table and Canadian hours of service, all today, is either remarkable or is answering a different question from the one you asked.

A vendor who says their tool models everything, today, is answering a different question from the one you asked.

Dated, and honest about it

Assessed from publicly published documentation as of August 2026. The arithmetic in this page uses the US federal limits on the Interstate System and a representative combination. The questions transfer; the numbers are worked examples.

Next

Related reading

Where the numbers behind these questions come from, and who is in the market.

Roundup

Truck routing services, compared

Six providers, what each is built for, and where each one stops.

Read

Field notes

Seven bridge formula mistakes

The implementation errors questions six and seven are designed to find.

Read

Field notes

Ten edge cases tools miss

Ten loads worth putting in front of a vendor during an evaluation.

Read

For how these questions are answered here, start withtruck routingand continue into grade, wind and fuel intelligence.

Next step

Put the routing-vendor checklist against one real load.

Bring the route, configuration or scale ticket that made the routing-vendor checklist matter. We will work through it in plain English and show where AxleGuard changes the decision.

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