About Priority vehicle: blue light + siren, both together: which statement is correct?
The same AND-requirement applies the other way: a siren without a blue beacon (e.g. during a test) does not yet make a vehicle a priority vehicle.
An ambulance with only the blue beacon on (no siren) is already a priority vehicle you must give way to.
Only police, fire brigade, and ambulance can be a priority vehicle.
A priority vehicle may always go first, even if that causes danger, such as by driving through a red light.
Explanation
trap: siren-is-enough. The same AND-requirement applies the other way: a siren without a blue beacon (e.g. during a test) does not yet make a vehicle a priority vehicle