The Carrefour de l'Arbre is the fourth-to-last cobble stone sector in Paris-Roubaix and with 17 kilometres to go one of the most important ones. There are quite a few spectators placed along the 2.1 kilometres of pavé, but it is also becoming a place for hooligans to hang out.
Hooligans are well known at football games and indeed there were so-called 'supporters' from a Belgium football club waiting for the riders. But they weren't there to cheer the riders on. "The spectators are vulgar and aggressive, without respect for the riders," said former French professional Martial Gayant to La Dernière Heure. "I had some guests in my car [following the race] and they were frightened."
Bjarne Riis had his rear-view mirror broken off and some cars in the caravane were hit with fists, beer and even rocks.
The riders didn't escape carnage either, as second-placed Filippo Pozzato (Katusha) confirmed to Cyclingnews after the race. "The Belgian fans were not very polite out there, I got spat on by someone."
Course director Jean-François Pescheux admitted that there is a problem. "The public shows a lack of discipline and the Carrefour de l'Arbre is becoming a critical sector," he said to La Dernière Heure. "We are looking for solutions but for the moment we haven't found any. Using barriers like in the Arenberg forest is almost impossible and without a doubt will only relocate the problem."
In bike racing it is impossible to close of the road completely and while most cycling fans are impartial and cheer for all the riders, incidents have always been around. In 1996 Basque fans blocked the road for the lead group with Bjarne Riis, as their hero Miguel Indurain was chasing several minutes behind.
In the 2004 Alpe d'Huez time trial both Lance Armstrong and Jens Voigt were insulted and spat on.
Bike racing is also a common place to hold protests, such as the Continental tire Company did in Paris-Roubaix. The staff was protesting the planned plant shutdown and blocked the start at kilometre zero, after the neutral zone ended.