It’s certainly plausible to decelerate rapidly by grabbing onto the pavement. You can decelerate even faster by running into a concrete wall. I suspect that 5g is more than the car (or its inhabitants?) can sustain without injury. I’m sure that digging into the pavement won’t go over well with the local highway department.
Note also that 50km/hr isn’t all that fast -- 31ish MPH I think—and that kinetic energy goes as the square of speed. So at freeway speeds, you’ll do proportionately more pavement damage.
I was skeptical of the injury potential at only 5g, since fighter pilots and F1 drivers routinely experience 3g acceleration; but this study%20933-9000 “pdf warning”) indicates that 5g is just over the threshhold for whiplash damage. This may also be due to the unusually good physical conditioning of fighter pilots and F1 drivers; physical conditioning certainly has the possibility of reducing neck damage.
More importantly, a pilot’s seat is significantly different from a driver’s seat, and they’re designed to hold the pilot in a way that limits relative movement of different body parts.
I would guess that the design of the device can be adjusted to give a smaller deceleration if needed to prevent injury. To minimize pavement damage, it’s probably a good idea to place the device under the automated control of an emergency stopping system that can detect imminent collisions and apply either the brake or this device depending on the deceleration needed to prevent the collisions.
It’s certainly plausible to decelerate rapidly by grabbing onto the pavement. You can decelerate even faster by running into a concrete wall. I suspect that 5g is more than the car (or its inhabitants?) can sustain without injury. I’m sure that digging into the pavement won’t go over well with the local highway department.
Note also that 50km/hr isn’t all that fast -- 31ish MPH I think—and that kinetic energy goes as the square of speed. So at freeway speeds, you’ll do proportionately more pavement damage.
I was skeptical of the injury potential at only 5g, since fighter pilots and F1 drivers routinely experience 3g acceleration; but this study%20933-9000 “pdf warning”) indicates that 5g is just over the threshhold for whiplash damage. This may also be due to the unusually good physical conditioning of fighter pilots and F1 drivers; physical conditioning certainly has the possibility of reducing neck damage.
More importantly, a pilot’s seat is significantly different from a driver’s seat, and they’re designed to hold the pilot in a way that limits relative movement of different body parts.
I would guess that the design of the device can be adjusted to give a smaller deceleration if needed to prevent injury. To minimize pavement damage, it’s probably a good idea to place the device under the automated control of an emergency stopping system that can detect imminent collisions and apply either the brake or this device depending on the deceleration needed to prevent the collisions.