Here's a cost that doesn't show up on your transport invoice, your auction statement, or anywhere you'd think to look for it: the floor plan interest you pay while a vehicle is still on the truck.
If you finance inventory, the clock on that financing doesn't wait for the vehicle to hit your lot. It starts the moment the unit is yours. Every day in transit is a day of interest on capital that isn't doing anything yet — not sitting on the lot, not in a customer's driveway, just rolling down the interstate accruing carrying cost.
It's a small number per vehicle. It's also one of the most predictable costs in your entire transport stack, which means it's one of the easiest to calculate, plan for, and shrink.
The math is a napkin away
You don't need a spreadsheet for this one:
(vehicle purchase price × annual rate ÷ 365) × days in transit
Take a $30,000 vehicle financed at 7% APR. That's $2,100 a year in interest, or about $5.75 a day. Run it over a typical transit:
- 4 days in transit → ~$23
- 8 days → ~$46
- 12 days → ~$69
Same vehicle, same rate. The only variable is time. And time, in vehicle transport, is the variable you have the most leverage over.
Why this is the layer transit time controls directly
Most of the costs stacked onto a transported vehicle are partly outside your control. Floor plan interest in transit isn't abstract like that — it moves in lockstep with one thing: how many days the vehicle spends in motion.
Cut transit from eight days to four and you don't trim the cost, you halve it. On a single $30,000 unit that's the difference between roughly $46 and $23. Across a month of volume, those halves add up into real money — and they compound with another transit-driven cost most dealers don't track either: auction storage, which keeps charging $25 to $50 a day every day a slow carrier leaves a vehicle sitting in the lane.
Faster pickup and faster delivery attack both costs at once. The industry average transit time leaves a lot of these days — and dollars — on the table.
A cost you can plan around
The reason floor plan interest deserves its own article isn't that it's the biggest layer in your landed cost. It isn't. It's that it's the clearest. You know your floor plan rate. You know your average vehicle value. The only missing input is transit time — and once you treat transit time as a number with a dollar sign attached, you start making transport decisions with that dollar sign in view. (To pressure-test it on your own shipments, the lane audit spreadsheet runs the floor-plan math per VIN, and the days-to-lot playbook covers how to compress the transit window that drives it.)
Every extra day has a price. Now you can name it.
Run it for your dealership
Floor plan interest is one of five layers between a transport quote and the true cost of a vehicle landed on your lot — along with broker margin, auction storage, manager time, and arbitration risk. The calculator pulls them into a single view so you can see what transit time is actually costing you.
Calculate your true landed cost — free, no signup required → AHX Dealer True Landed Cost Calculator
Plug in your floor plan rate, average vehicle value, and volume, and watch what happens to the total as transit days move.
Want to cut the days, not just count them? See how Auto Hauler Exchange delivers.
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