Beyond velocity and acceleration: jerk, snap and higher derivatives (2016)

I wish designers of vehicles - particularly cars, trains and busses, would work to minimize jerk, snap and crackle.

Turns out if you minimize those, you get a far more comfortable ride. It matters far more than acceleration.

Finite element models of the whole system (tyres and suspension components and flexing elements of the vehicle body and road/track) can quickly allow analysis of the jerk, snap and crackle, and allow tuning of damping and drive system control loops to make a far more comfortable ride.

Do you have proof for that, or is this like audiophiles asking for gold connectors because "they make the sound better"?

I used to work at a self-driving car company, and all the vehicle's motion was planned around how much jerk to apply.

Your muscles are pretty good at applying a constant force (or responding to a constant acceleration). Hold your arm out straight: it's no effort to keep your arm still and counteract the force of gravity. Now imagine gravity varies quickly and randomly between 0.5g and 2g. I guarantee your arm won't stay still.

The same prinicple applies on a bus or in a car, except this time the forces are smaller, and it's your neck keeping your head still!