Not letting through an ambulance is a different question, and obviously it depends on the volume of traffic it can be done safely. Yes on this image it's clear they are doing it wrong, but as I've seen in other posts not letting through an ambulance is mostly an american thing only. Here if you don't give way to an ambulance deliberately and a police car sees it, they can confiscate your driving license on the spot, so this is not really a problem here.