"due regard" = "safe and expedient" - and in my RFS there's an SOP that limits most vehicles travelling lights and sirens to not more than 20 km/h (about 12.4 mph) over the speed limit. Not law, but if you're driving outside the SOP's and are involved in an MVC, then watch out because the Court will crucify you. And rightly so, fire trucks are not designed, built, or loaded to be driven like a pursuit car.
our law in michigan is 5 over, but with a firetruck and the hills, its hard to get the truck over that anyways, but pov's have to watch it, and we're real picky on who gets lights and sirens on their pov:)
2 years ago we had a neighbor department in Traverse City hit a car at an intersection with a pumper going down a hill, it was nasty................ a mom and daughter died and the dad was ok and the firefighter who was responding to a chimney fire and only had been a firefighter for a year is now in prison. Its not worth it to speed at all!!!!!!!!!!!
Several years ago we had a State Trooper give us a safety class and he said that you can drive above the speed limit but you had to drive at a safe speed then he said if you are driving slower then the posted speed limit and have an accident it was an unsafe speed kinda a catch 22 huh.