I think the speedometer is driven by the driveshaft. It the accelerator was still depressed the indicated speed would increase quickly.
Once the car went air-born, wouldn’t the drive wheels spin much faster due to loss of friction? (Assuming the driver’s foot was still pressing on the gas)
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They might stop spinning altogether if the car had a limited-slip differential. Once airborne, the wheels would sense loss of traction and the anti-slip system would kick in to release the wheel from the drive.
What's telling to me are two things. One, no marks on the highway or shoulder. If this was an accident - driver distracted momentarily etc. you would expect some attempt at correction - braking and or turning. That should leave significant, easily identifiable marks in the dirt of the shoulder of the road. I've seen this first hand - witnessed a motorcycle accident, and after assisting with getting the rider life-flighted out helped fire and police investigators find the exact point at which he departed the roadway - for measurements and speed estimation based on where he and the bike came to rest (he was flying, literally and figuratively).
Two, they said there were no marks on the hillside, the vehicle impacted in the tidal area. That does point to a fair amount of reckless and/or intentional speed to "fly" over the hillside and land in the flat. Again, it depends on the height and slope, but investigators will be able to estimate speed fairly well from this. Generally speaking, you've got to be going very fast because that 32.174 ft per second per second acceleration begins moving you down very rapidly. To clear an obstacle (ie. not impact the hillside) you've got to have a lot of horizontal speed and/or a bit of an up vector.
Absolutely.
My first thought.
They were driving a 2003 Yukon. GM vehicles since 1996 have an EDR, like an airplanes black box, that records vehicle data for the last seconds before a crash. The police have more information than is being released.
Either way, it was an intentional killing.
I’d think it would be a simple physics calculation of speed and gravity...much like a ballistics chart that could calculate how much horizontal travel from the cliff edge a car travelling at 90 mph would make before gravity won.