At the crossroads, there was a traffic light.
A big truck, a horse-drawn wagon and a motorcycle rider are all standing and waiting for the green light.
As soon as the trucker saw that the light is about to turn green, he hit the gas. The horse was frightened by the sound and bit motorcycle rider's ear.
A policeman was called, and figured out that he ought to give somebody a ticket, since some rule was definitely broken to contribute to the resulting trauma.
The cop is honest, so won't lie on a ticket. Who got the blame and the ticket for breaking the rules?