Nitpicking..... Traffic collision just means it was a moving motorized vehicle, it does not imply two vehicles.
I am not here to debate the precise meaning of the word. That phrase for a lot of people would imply two vehicles colliding. That's all...trying to explain why people might assume it involved more than one car.
Easy misunderstanding.
At the same time it does not mean it was a single car accident either.
We will have to wait and see what is said.