Earlier quoted context omitted.
You just made me look up the rules in germany. The wording is somewhat particular. "An emergency vehicle following a higher cause can invoke special rights ("Sonderrechte") indicated by blue flashing lights. These special rights authorize the driver of the vehicle to divert from the regular traffic laws as long as done safely." Interestingly, this is separate from the "Right of the way", which can be ordered on top u…
> which can be ordered on top using a siren. This is why they need to run the siren for 2ish seconds before running a red light for example. Pretty sure that's because people need time to notice the siren and take appropriate action, not because of some rule
And that's why there is a rule for drivers of emergency vehicles to sound the siren for at least 2 to 3 seconds when approaching an intersection with an intent to disregard other peoples right of way. The rule for normal traffic partakers is very much "If it flashes blue and has music, get the hell out of the way as fast as you can without endangering yourself"
This rule in turn is in contrast with the overall suggestion to keep siren usage low, because it's loud, disturbing for bystanders and not great for the hearing of the people inside the car.