Three-Way Match for Traffic Control Purchases: Order, Receipt and Vendor Bill

A flatbed pulls into the yard with a load of drums and barricade rails. Someone counts it, signs the driver's paperwork and goes back to loading trucks for tomorrow. Three weeks later a bill arrives in the office. The person paying it was not in the yard that morning, may not have placed the order, and has one question: should we pay this?

A three-way match is the routine that answers that question with documents instead of memory.

The three documents

The purchase order. What you agreed to buy, how many, and at what price. It is written before anything ships, which is the point. A price agreed in advance is a price you can hold the vendor to.

The receipt. What actually arrived, counted by the person who unloaded it, on the day it came. Not the vendor's packing slip, which says what they meant to send. Your count.

The vendor bill. What the vendor is asking you to pay.

Each comparison catches a different problem.

• Order against receipt catches short shipments, the wrong item, a substitution nobody approved, and backorders. A pallet of drums that came with the wrong ballast is a receiving problem, and it should be found in the yard, not in the office a month later.
• Receipt against bill catches being billed for something that never arrived. This is the most common gap in practice: a split shipment where the bill covers the whole order, or a backordered line billed anyway.
• Order against bill catches price drift. A list price that changed between the quote and the shipment, a freight charge nobody mentioned, a quantity rounded up to a full case.

When all three agree, pay. When they do not, find out why before the money goes out.

The government version of the same idea

Federal agencies buy under this exact discipline. The Federal Acquisition Regulation says: "Payment will be based on receipt of a proper invoice and satisfactory contract performance." It adds that invoice payments "must be supported by a receiving report or other Government documentation authorizing payment" (FAR 32.905). The receiving report it describes has to show, among other things, the quantities received and accepted and the date the supplies were delivered.

You are not a federal agency, and nothing here says that rule binds you. It is useful anyway, because it shows how the largest buyer in the country thinks about paying: the invoice alone is not enough. Someone has to say, on the record, that the goods came.

Why separate the people who do each step

The control works best when the person who orders is not also the only person who receives and approves the bill. The federal internal control standards, known as the Green Book, put it this way: management "considers segregation of duties in designing control activities so that incompatible duties are segregated," and it names the duties to keep apart as those "related to authority, custody, and accounting of operations" (GAO, Standards for Internal Control in the Federal Government, 2025 revision, paragraphs 10.21 and 10.22). The same document says it may be adopted by nonfederal entities as a framework.

The part most useful to a small traffic control company is the next paragraph. When segregation "is not practical within a business process because of limited personnel or other factors, management designs alternative control activities" (paragraph 10.23). In plain terms: if you only have two people in the office, you cannot split every duty, so you add a review instead.

A workable version for a company with a handful of office staff:

• The yard lead records what arrived, on the day it arrived.
• Whoever placed the order does not mark their own order's bill approved without someone else seeing it.
• The owner reads the flagged bills and the list of goods received but not billed, once a week. Ten minutes, on a fixed day.

That review is the alternative control. It does not need to be elaborate. It needs to happen every week.

Choosing a tolerance

Requiring every bill to match the order to the cent sounds strict and works badly. Freight gets added. Sales tax is calculated differently. A vendor rounds. If every one of those flags the bill, the person reviewing learns to approve flags without reading them, and the control is gone.

A tolerance is the size of difference you accept without review. A few things to think about when you choose one:

It is about attention, not approval. A bill inside the tolerance is not automatically correct. It is just not worth a second look by default. A bill outside it is not automatically wrong. It is unexplained.

Know your normal differences. Write down what is routine for each vendor, such as freight on large drum orders or a fuel surcharge from a sign shop. A reviewer who knows what to expect can clear a flag in a minute.

Watch the small, repeated gap. A tolerance hides a small overcharge on every order. Once a quarter, look at what you paid each major vendor against what you ordered, in total. A difference that never trips a flag can still add up.

Fix the order, not the receipt. If the vendor's price really changed and you agreed to it, update the purchase order. Never change the receiving count to make the numbers agree. The receipt is the one document that records what happened in your yard.

Partial deliveries are normal

Device orders often arrive in pieces. Drums come on one truck, ballast on another, sign panels from the fabricator two weeks later. Each delivery should be recorded against the order as it comes, so the order always shows what is still outstanding.

Two things go wrong with partial deliveries. The vendor bills the whole order after the first truck, which the receipt-to-bill comparison catches. Or the vendor bills each shipment separately and one bill gets paid twice, which a single order with its receipts and bills in one place makes obvious.

Receiving in parts matters beyond accounts payable too. What you received is what you have. If the receipt is right, the yard count is right, and the inventory record you rely on for cycle counts starts from the truth. If you cost devices from what you paid for them, the receipt is also where that cost comes from, which is why it feeds job costing and margin.

When the three disagree

A short checklist for the person holding a flagged bill:

1. Find which comparison failed. Order to receipt, receipt to bill, or order to bill. Each points to a different conversation.
2. Call the vendor before you short-pay. Paying less than the bill without saying why creates a balance on their side and a dispute later. Ask for a corrected bill or a credit memo.
3. Write the reason on the order. Six months from now nobody will remember why that bill was paid at a different amount.
4. If goods are missing, chase them. A backorder is still owed to you. Note it on the order so it is not quietly forgotten.

The broader purchasing process around this, including approval thresholds and how to treat different kinds of vendors, is in our guide to purchase orders and vendor management.

How Traffic OS handles the three steps

In Traffic OS purchasing, a purchase order is sent to the vendor with a public link. When the goods come, the order is received in parts, delivery by delivery, so it always shows what is still outstanding. When the vendor's bill arrives, the received order is turned into a vendor bill, and the bill is compared with the purchase order. If the difference is outside the tolerance, the bill is flagged for review instead of going straight through.

What you received also builds the inventory record. Cost layers come from purchase-order receipts, so the margin report uses what you actually paid. And anything received but not yet billed shows on the unpaid-bills report in the reports, which is the list the weekly review should start with.

None of this replaces the person who counts the delivery. Software can hold the documents side by side and point at the ones that disagree. The count still has to be honest, and someone still has to read the flags.