The new overhead cameras you see at the Mount Hermon Road/Scotts Valley Drive/Whispering Pines Road intersection are solely for detecting the presence of vehicles in order to provide the best distribution of green time based on traffic demand. They are cost-effective replacements for in-ground induction loops that are cut into the pavement.
The cameras are not focused the driver, but rather the vehicle as it moves towards the intersection. As the vehicle enters defined areas or "zones" within the camera's field of view, the camera's processor detects a change in the "zone." An output is sent to the traffic signal's controller (the computerized "brain" housed in a nearby metallic cabinet controlling the intersection's timing) that says a vehicle is requesting green time for its direction.