Previous research found no significant sales effect on supermarket products for other forms of outdoor advertising.

We commissioned the University of Groningen to investigate whether the same applies to Moving Billboards.

WHAT THE RESEARCHERS PROVISIONALLY CONCLUDE

01 Moving Billboards have a significant positive effect on sales. Both on the number of orders and on revenue.

02 For other outdoor advertising, previous research found no significant sales effect. For Moving Billboards, it now does.

03 Comparable to TV advertising, according to the researchers. For a fraction of the budget.

HOW THEY COMPARE IT

To fairly compare media, researchers do not use reach or CPM. They look at the percentage effect when advertising is increased by one percent. It then doesn't matter whether you measure in kilometres, seconds, or euros. You compare effect with effect.

"The effect of trailer advertising is of the same order of magnitude as what has been found in literature for television advertising for supermarket products," says Maarten Gijsenberg, one of the researchers. "That is quite remarkable for a medium that incurs a fraction of the costs. We were quite surprised by this ourselves."

"Direct sales effects of advertising are usually small in absolute terms, for any medium," says Gijsenberg. "That is why you look at the ratio. And in that respect, trailer advertising is on par with television, whereas previous research found no significant sales effect on supermarket products for other types of outdoor advertising."

That is a comparison with the literature. TV was not measured in this study.

AND WHY IT IS PROVISIONAL

"We now have six months of campaign data," says Gijsenberg. "The effect is there, it is significant, and it seems quite robust to us. Precisely how the comparison with other media turns out may still shift as the dataset grows. That is why we call this provisional."

Provisional does not mean the effect might disappear. It means the strength of the effect may still adjust. The researchers will conclude the study this year.

WHAT WAS ACTUALLY MEASURED 

Each trailer was fitted with a GPS tracker that recorded its position every five minutes. Movements shorter than ten minutes or one kilometre were removed. 

What remained was converted per postcode area per month into kilometres driven and dwell minutes. And placed alongside the orders and net revenue in that same area.

No surveys. No recall research. Orders versus kilometres.

THREE REASONS WHY THIS IS NOT MARKETING RESEARCH

the routes were not ours

The haulage companies determine where they drive, based on their loading and unloading addresses. The advertiser has no influence over where or when a trailer appears.

That sounds like a limitation. For a measurement, it is the best you can have. The exposure is not directed by anyone with an interest in the outcome. It is the closest approximation to an experiment you can get in practice.

see first, buy later

If you see a trailer on the fourth of the month and order on the fifteenth, one could have caused the other. Not the other way around. In monthly data, those two situations look identical.

That is why the researchers did not look at the same month. They looked at sales in the following month. Then the sequence is fixed. First the kilometres were driven, then the order came.

two models, the same outcome

The baseline model treats each postcode area separately from the rest. The refined model allows for advertising in one area to also influence sales in adjacent areas. After all, people travel an average of thirty kilometres per day.

Both models confirm the effect, in the same order of magnitude.

OUR FIRST CHART SUGGESTED IT DIDN'T WORK

National revenue before the campaign started. National revenue afterwards. The line went down. The researchers even noted: this doesn't look great. But are we looking at it properly?

No. That comparison lumps all 789 areas together, including areas where not a single trailer drove that month. You then measure the season, the weather, and the market. Not the advertising.

If you do compare areas with trailer kilometres against areas without, in the same month, the picture reverses: significantly higher sales.

the lesson Evaluating a campaign based on a before-and-after chart is not measuring. It is guessing with a chart attached. Anyone wanting to know the effect needs a control group. Outdoors too. Offline too.

We could have left this chart out. Then you would have had to take our word for it. That is precisely what we are trying to unlearn in this industry.

THREE THINGS TO FACTOR IN

it impacts your volume and your order value

The effect is visible on both the number of orders and net revenue, and on revenue it is larger. That tells you two things at once: people order more often, and they spend more on average per order. If the effect on revenue had been the same size as on orders, all growth would have come from extra orders. Now, part of it comes from a higher order value.

Our interpretation: that aligns with a brand effect. Those who know and trust you compare less on price.

the effect lies in the preceding month

Only the kilometres driven in the preceding month have a demonstrable sales effect. Further back is no longer significant. Brand awareness is not something you own. You rent it. That applies to virtually every medium, but almost no one in the industry says it out loud.

every kilometre lands where you drive it

No measurable spillover to adjacent areas. No leakage, no dilution. You are not buying a spot where people pass by. You are buying an area where your brand goes. And so the fleet you use is a strategic choice, not a logistical detail. 

WHAT THIS RESEARCH DOES NOT SAY 

When you claim you only state what you can substantiate, the list of what you don't substantiate belongs there too.

not — that it is scientifically proven.
One advertiser, one product category, twelve trailers, about six months of campaign data. The researchers call their results provisional. So do we.

not — that we are better than television.
It says comparable, measured for supermarket products. Turning comparable into something else is precisely the stretch we are against.

not — what a single euro returns.
The elasticity has not been published as a figure. And is small in absolute terms. That applies to virtually all advertising. That is why you look at the comparison and not at the isolated figure. But a promise of ROI cannot be made on this basis.

not — that we steer the routes.
The hauliers determine the journeys. You choose the fleet, and with it, the catchment area.

not — that this is the final word.
More data will follow, and the outcome may adjust. We took that risk when we asked a university to investigate.

about the study — “on a highway to sell: how effective is truck trailer advertising?”, conducted by Veronica Burbulea, Maarten Gijsenberg, and Tammo Bijmolt of the University of Groningen, Faculty of Economics and Business, Department of Marketing. Data: GPS tracking of twelve branded trailers and monthly sales data from a nationwide e-commerce advertiser, across 789 three-digit postcode areas, January 2024 – February 2026. Method: spatial econometrics with location and time fixed effects and a one-month lag between exposure and purchase. Results are provisional and based on approximately six months of campaign data. The comparison with other out-of-home media refers to Frison et al. (2014).

questions about the methodology or the figures? — we will send you the substantiation. That's the whole point.