Brazil Nut Effect in Roads that Allow Cars and Motorbikes to Pass Through

In some countries, cars and motorbikes are allowed to pass through the same road. We observe a phenomenon similar to a Brazil nut effect (BNE) that frequently occurs on such roads, in which motorbikes (representations of small particles) segregate in front of cars (representations of large particles), although the motorbikes are initially located far behind the cars. Deep investigations of the BNE-like phenomena in such roads are reported here, where a combination of aerial views using a quad-copter camera and simulations is studied. We show for the first time that most phenomena observed in common BNEs are also observed in such roads.