I don't know what the law is here but in Canada, the driver who has the last clear possibility to avoid the accident and doesn't take it is at fault. Perhaps that's the view of the policemen/law here? It doesn't matter that there was a yield sign, you had the opportuniy to avoid the accident and you didn't take it?

I'm still not saying you were at fault but if that's the law, you might have to accept it.

Signature line > "You can't fix stupid"