even as a car driver i've always wondered why buses dont have some kind of way of communicating with the traffic lights to give them priority>

Thinking back im sure the buses leaving the old haymarket used to get this as when buses pulled up to the light they always seemed to turn green instantly and when no buses were there they stayed red allowing traffic to flow on Percy street? I though there was a sensor in the ground that change the lights to green when the bus rolled over it.