Could ask the similar questions about police sirens while the car is traveling at high speeds. When I watch a police cruiser shoot down a residential street crowded with cars and pedestrians 60-70 miles per hour (or faster), running its lights and sirens at full blast, I often ask myself if the immediate risk of hitting someone is worth whatever advantage of time they achieve by arriving at the scene 2-3 minutes sooner.

A few times, I've seen police or ambulances race up to a building where they've been called, then get out and loiter while waiting for something else--immediately burning off whatever time they'd saved by speeding and running their lights.