This happened to me this morning:
Red 2005ish Escape, regular WI auto plates (official vehicles have beige plates with a star if law enforcement, and certified EMTs and Firefighters can get special plates), I look up as I'm about to slow for the roundabout, and I see it close to my ass with a red and white LED visor light flashing at me. I see the plates and am like "Fuck is this guy?"
I make my way through the roundabout, figure he'll jet past me in the upcoming turn lane for the school, and the damn Accord (must have seen the lights flashing) pulls over. So I pretty much had to as well.
In no hurry, the Escape passes us, and turns down the access road that leads to the middle school, high school, and athletic fields on the left.
Not to doubt the driver's validity of being an emergency responder, but dude. Use the horn. Get a siren. Get special plates like my one ex-coworker had when he got pulled over (that's a story for another day).