I remember this sooooo well. Part of the great life we kids of the 50s had. The killer was the smile on the Sanitation drivers grin as he washed the fun away with the water truck. Luckily the summer sun would dry the streets quickly and we would start again.
Not a shock wave, that’s a water track from a 800 plus foot long with 40 ft draft battle ship being pushed sideways from recoil of all the 16in guns firing in same direction.
I love the look of the slant of the grill. MacTexas, I don't know if that 34 in your avatar is your car or not, if it is, it's a good call.
For what it's worth. Here's my guess of what happened. The hood is open, so I'm assuming he pulled to the side of the road because he was having mechanical problems. Then the snow plow came by and buried him.