TU Delft researcher reveals Greek licence plate scam

6660, the devil’s number (well, almost so if you remove the zero). Or 1111, another catchy digit sequence that makes you stand out. Greek drivers with unusual number combinations in their licence plates are likely to have paid bribes to get them shows research by TU Delft Professor of Software Analytics Diomidis Spinellis (Electrical Engineering, Mathematics & Computer Science Faculty), that appeared this week in the scientific journal PLOS ONE.

From 2009 to 2011 Spinellis, who also works at the Athens University of Economics and Business, was Secretary General for Information Systems at the Greek Ministry of Finance. The corruption he saw around him was a thorn in his side. Right after his work as a senior official at the Ministry he conceived the plan to investigate licence plate fraud. He tells Delta about it. He chooses his words carefully. In a previous case he alleged another well-known form of corruption and was sued for slander by the tax officials’ union heads. “It took me many years and considerable expense to settle the case.”
 

Diomidis Spinellis hopes his work will wake up officials. (Photo: TU Delft)

Interlaced pairs and palindromes

Greek licence plates consist of three letters and four digits, Spinellis and his co-author Panos Louridas write in their article entitled Conspicuous corruption: Evidence at a country level. The letters cannot be tampered with as they are linked to the region of issue. But the numbers are issued sequentially. Officials could keep certain striking number combinations that are in demand on hand and sell them. Take for instance the following distinctive patterns: xxxx (all same numbers), x000 (thousands), xxyy (two pairs), xyxy (two pairs interlaced) or xyyx (palindromes). If you have a plate with these digits on your car, you can show off.
 

What exactly did you look into?
“Expensive fancy cars often have vanity licence plates. Given that there is no legal way to obtain these plates, their prevalence could be explained through under-the-table corrupt deals. In effect their owners exude that they are above the law. Everyone knows this in Greece. But is it really the case, or are we just imagining it because we pay extra attention when we see expensive cars pass by? My colleague, Panos Louridas from Athens University of Economics and Business and I wanted to figure this out by analysing data.”

In some countries, including Belgium and Britain, governments make millions from auctioning crazy vanity plates that say HAHAHA, for example, or PIZZA. Isn’t the sale of license plates in Greece a bit similar to that?
“No. It is a corruption deal. Greece could also make millions from auctioning special licence plates. Now the money probably goes to corrupt car dealers and officials. It is an overt form of corruption. It makes others think that you obtained your license plate illegally and as a consequence, as the car owner, you might derive status from the plate. If you steal a painting, you hide it in your basement. This, on the other hand, is open and exposed.”

But you can also get lucky and be assigned 1111 or something similar by chance, right?
“Yes that’s right. We can’t prove that corruption is involved in every individual case. However, statistical analysis has shown that it is highly unlikely that all the allocations are coincidental. We analysed more than five million licence plates and looked at whether certain luxury car brands had more striking combinations of numbers. And we looked at whether there was a connection with the size of the engine.”

And so they appear to be especially prevalent in cars from expensive brands like Mercedes, BMW and Jaguar?
“That’s right. This indicates that there is fraud. On average, cars have an engine capacity of 1,439 cm3, but the cars with any type of vanity plates have an average engine capacity of 1,586 cm3. More strikingly, cars with plates like 5555 have an average engine capacity of 1,940 cm3.”

Why did it take 10 years to complete this research?
“According to, quite progressive, Greek law, all Government data must be public. But in practice governmental bodies are very reluctant to release information. We had to appeal to the Freedom of Information Act before we finally got the data which officials had anonymized by garbling the plates’ letters. It took years.”

Do you expect this investigation into licence plate fraud to bring about a small change in anti-corruption work in general in Greece?
“I hope so. Greece does very poorly on the corruption-perception rankings compiled by Transparency International, so there’s certainly room for improvement on many fronts. The news has been picked up by various international media. But at the same time, I believe that Greek politics is now concentrating on other issues, such as covid, the climate crisis and all the wildfires in the country.”