This is a classic theme for motion blur and it's nicely done. My initial feeling about this shot is that the exposure is too long. I think that if you re-try this photo and shoot it at f/11 and 10 seconds, you will probably see a huge improvement :)
The way color was processed in this image gives it a surrealistic quality that perfectly supports the accident scene as the main subject. It gives the viewer that "been there, feel for you" reaction. The quality of this image is outstanding and is a wonderful variation of the "streaking car headlights on the freeway" cliche. It is one of my personal top three for this challenge.
I do like this image - though I'm not sure if the road incident adds or detracts from the overall shot. In my humblest opinion, the action to which the title refers isn't prominent enough in the overall crop to make a striking impact - I wonder if the shot might not work better a little closer to the police van, and cropped so it's without the admittedly nice, blue sky. The impression of speed from the lights is a good touch - the world going on around the vehicles works well. A bit of noise reduction might have helped, though (as would editting out the yellow slodges of glare). I think it fits the challenge pretty well, and I think i'd like to award a 6.