QUOTE(moregon @ Nov 8 2006, 08:54 AM)

Hwy 101 is not a superhighway, nor is it a lonesome country road somewhere in the middle of nowhere. My first thought was dropped from an overpass like many, yet at the same time I've driven this route in the past and know there isn't any overpasses. I am surprised that at 11:40am nobody saw where the rock came from, as this is still a fairly well traveled route.
From the viewpoint of pure speculation of where a rock of this size could have come from, I can think of a couple of ideas, that don't involve anyone purposely throwing it, UFOs, ultralights or other hard to believe means of delivery. Both ideas I'm thinking of involve other vehicles, and possibly happened so fast it simply wasn't noticed.
1. Truck, either dump truck or logging truck. In the case of a dump truck it could have simply fallen out of the load. It could have been traveling from either direction, but most likely if it passed by the victims truck going in the opposite direction. If a rock would fall off the dump truck it would hit the ground and still be traveling at the same speed it had been while in the truck. Jagged edges could cause it to pop up into the air and hop. So how far can a 10 pound rock travel that's been propelled at 50 or 60 mph? In the case of a logging truck it could have been stuck into a tree that it was carrying, but more likely stuck between a set of tires. The tires under the logs are like on normal semis, one tire next to another. It's not uncommon at all to find large rocks stuck between these tires, especially if the logs are being brought out from a heavily wooded area with unimproved roads. Usually the rocks are lost long before the truck ever hits the pavement, and I'm sure MOST drivers stop and check before entering the highway to make sure such a hazard doesn't exist.
2. The other possibility is that the rock was already on the roadway, and someone may have just clipped enough of if with the tire of their vehicle to cause it to flip and fly, much like a Tiddley Wink.
I lean heavily towards scenerio number one mentioned by Moregon. Most companies try to make sure the drivers check their tires before hitting the road. Some don't. In this specific case, the OSP believe the rock came from a truck. It happens more frequently than it should. Several years ago, a little girl who went to school and Tae Kwan Do lessons with my nephew was a passenger in the front seat of her moms car. A five pound rock was kicked up from the road and came through the windshield. The girl suffered severe head trauma. The OSP eventually found that the rock came from between the double tires of a truck. I tried to find the link to this story, but couldn't. It happened about 8-9 years ago in the Newberg area.
My own experience with road debris was scary.
In 1993 I was living in the Seattle area and driving down to the Salem area a few times a month to visit my boyfriend (now husband). I was driving Southbound over the Interstate bridge when the cars ahead of me started to swerve. Within seconds, a large square piece of road grating (the kind they use to temporarily cover holes that crews make in the road when working) hit the top of the drivers front quarter panel on the car in front of me and flipped back onto the road directly in front me. It was airborne momentarily, but I was driving far enough behind the car so the panel actually hit the road before I went over it. Had I been traveling any closer to the car in front of me, I feel certain the piece of grating would have hit my hood/windshield. The damage went right down the center of the undercarriage of my car. Honest to goodness that dang thing was airborne and it had to have weighed a whole lot more than ten pounds.
Obviously, it is more likely that the rock was kicked up or dropped from a load than alluding to a sasquatch throwing rocks at passing vehicles....in broad daylight....near a very busy highway.
Just my 2 cents worth
Redwolf