The Royal Palace of Amsterdam has encountered a serious public peeing problem. However, help was provided by an unexpected source. But first, economist Robert Dur had to plough through more than six month’s worth of security imagery.

You name it, it had already been tried: warning signs, fencing, and surveillance. But Amsterdam revellers– or their bladders, rather – couldn’t be controlled. Night after night, the Royal Palace became the capital’s piss-pot. Not such a problem, surely, I hear you say; that’s what you get in such a tourist hub. But besides being unhygienic, the necessary clean-up work resulted in extensive corrosion of the sandstone facade. So, when the Palace was finally as good as new again after thorough renovation works, the Central Government Real Estate Agency sought a strategy to keep it that way. Enter Robert Dur, who was given the task of sorting it out, together with his colleague from Tilburg, Ben Vollaard.

Robert Dur

Geert Maarse is interviewing researchers for the ‘Scientist Cowboys’ series who go that extra mile more than their colleagues. Robert Dur is a Professor of Economics at the Erasmus School of Economics. His research study into the effect of lighting on public pee-ers (together with crime economist Ben Vollaard from the University of Tilburg) resulted in the problem around the Royal Palace sharply declining. Previously, he had researched the illegal putting out of additional bin bags in Rotterdam. Recently, he won the ESE Societal Impact Award.

How many public pee-ers are we talking about here?

“Some quite tall stories were being bandied about, mostly based on particular days such as King’s Day. But, taken on average, we’re talking about more than twenty over a weekend, with a peak on Fridays and on Saturdays between two and five a.m. Is that a lot? Well, it’s enough to have the staff going round every day spray-cleaning it all up.”

What did you do?

“Security cameras were installed all over the Palace that record everything, which gave us the opportunity to keep an eye on all that was going on. Firstly, we took a baseline measurement, when we simply tallied the amount of public pee-ers. Lights were subsequently installed around the Palace, which we then played around with. During random time slots, we looked at what happened with the public pee-ers when the lights were switched on, either permanently or with a motion sensor light.”

Artist’s impression of the Royal Palace of Amsterdam, with the installed lighting.

Paleis impressie 4
Artist impression van Het Paleis op de Dam, met de aangebrachte verlichting. Image credit: Rijksvastgoedbedrijf

Why is this interesting to a scientist?

“We research human behaviour. From time to time, under laboratory settings, we’ve researched how light affects illegal behaviour, for example, having students play games in a large space where they can hoodwink one another. It transpired people started to nick things more and to deceive each another more with the lights dimmed. We wanted to know if that would also be the case in reality. Just as my colleague Jan Stoop is also assessing, it’s about whether the lab is predictive for experiments out in the real world.”

How did you end up in cahoots with the Central Government Real Estate Agency?

“We just had a phone call from someone in the Joint Administrative Consultation Committee of the Central Government Real Estate Agency, Amsterdam municipal council and the Royal Household. They’d heard about our domestic waste research study in Rotterdam and said: “we have something that’s along the same lines, and perhaps you know how we can tackle it?” There was a list outlining possible measures, which we started to test out. It’s crazy they didn’t just get started on it, but it is in my field of interest. Not that I’m a fan of public peeing, but I find it invaluable as a scientist to undertake research together with policy-makers and implementers; in this instance, in the public arena. There is a great deal of scepticism about the feasibility of these types of experiments. So it’s great to then show it is indeed possible.”

How long did you end up trawling through the security images for?

“Together with my fellow researcher, Ben Vollaard from the University of Tilburg, I scoured the Palace’s security images for seven months. Luckily, they have video software that automatically traces the fragments in which someone approached the Palace. Initially, we were keeping an eye on every evening and night. But it soon became apparent that not much happened on Sunday, Monday, Tuesday and Wednesday nights. So we very quickly focused on Thursdays, Fridays and Saturdays. From five o’clock in the afternoon to eight o’clock in the morning. The images weren’t saved for long which meant we had to run through them weekly. So we couldn’t head off on an extended holiday for quite some time, for instance.”

Did you stumble across any friends?

“No. Well, my co-author encountered me once when I was walking around the Palace after a vigil. He got a fright alright.”

De verlichting, die geactiveerd wordt door een bewegingssensor, leidt tot een halvering van het aantal wildplassers. Image credit: Rijksvastgoedbedrijf

Did you see any other weird and wonderful things?

“That really depends. (laughs). Or rather, it depends on your stance.”

No drug deals or couples believing themselves unobserved?

“Very occasionally. I think such a couple about once a month on average. And in all that time we saw what looked like a drug deal two or three times. Very often, you think to yourself: now something’s going to happen. But that’s often what we call false positives: people parking their bikes, slouching around, smoking a cigarette. You barely get people being caught red-handed.”

Why don’t they just surveil the Palace?

“That’s too expensive. Just think. We’re talking about more than twenty public pee-ers each weekend. That’s seven a night, under one an hour. That’s not enough to warrant surveillance. Moreover, the risk of being caught is far from 100%. It could be that the patroller just happens to be on the other side of the Palace.”

Most of the people reading this article are young researchers. You’re a professor. Isn’t your time too expensive to be doing the donkey work for hours on end?

“As we trawled through the camera images ourselves, we got to see the shock effect firsthand. Normally, you only see the effects back – even when doing field work – when you open the Excel file and start running the statistical tests. The advantage of getting out there yourself, I think, is that you learn a great deal about the context. You can ask me anything about this experiment and I’ll know the answer – which comes in handy when presenting at a congress or seminar. Not only that, I’m not sure I’d use young researchers on a project such as this.”


“It does involve some level of risk. With this type of thing it’s about whether it will lead to something that’ll be valued within Economic Science. It can just suddenly happen that it is published in a psychology magazine. I think that’s great; I’m proud of that. But if you’re a young economist who’ll imminently be entering the economics job market, then your career would gain little from it.”

How much peeing is taking place now?

“I don’t know exact numbers at this precise moment in time. The estimate we now have is that the number of public pee-ers is being halved with motion sensor lighting. And they’ve put a toilet there too, one of those that comes up out of the ground. That has also resulted in a considerable drop. I believe numbers have dropped from twenty each weekend, to a handful.”

What else will happen with this research?

“The lights are up in Amsterdam. We are hoping we will be given another opportunity to learn more in the field as to why this works. The motion sensor lighting works really well around the Palace. We believe one of the reasons is that when that light comes on, people spontaneously look upwards to see where the light is coming from. And then they see the camera. That could have the implication that wherever you hang a camera, you also hang a motion sensor light. Simply to highlight to people: you’re not an anonymous entity here at nightfall.”

It seems a little unsociable to me, a spotlight like that in your face wherever you go.

“Me too. But if you can avoid large-scale devastation to this type of historic building using a simple motion sensor light, then perhaps it’s a good idea. And the exceptional thing about the Royal Palace is that it isn’t surrounded by fencing, which is very often the case with similar buildings abroad.  Which is also a little unsociable.”