Rigid trucks arn't too bad because of the long wheelbase, but artics can have terrible ride quality, worse since drive axle air suspension arrived on some premium makes quite how they managed that is a mystery.

Things have improved since the days i started, they were real bone shakers then and no fancy seats until new foreign trucks started arriving in the 70's which were a revelation in driver comfort.

Most of the lumbar support airbags in the back of the seat i deflate, though there's a few Quasimodos about judging by the adjustments of the seat when i get back in, i have the vertical damping set about half way and thats it, about the only cars with enough headroom for fully damped seats woiuld be large 4x4s and people carriers, but the ride is good on them (unless some clown has opted for elastic band tyres) there's no point.

The simple answer is because the seat height is maintained by air tanks that supply the braking system, when you go to a truck in the morning and there is no air in the system you will only see the seat rise when there is sufficient air.

Why not in car ? You cannot have powerful air brakes in cars as they are too light and would be dangerous in such a light vehicle, and they are expensive to install and maintain when they go wrong, you would also need an air tank to hold the air.

There's a number of cars which get air adjustable suspension, either as standard or as an option - my VW has it - it wouldn't be difficult to extend that system to power an air-sprung seat - whether the cost would be justified is another matter.

<< it wouldn't be difficult to extend that system to power an air-sprung seat - whether the cost would be justified is another matter. >>

You might need some more headroom ?

I'm 6' tall, I have the seat on its highest position without being close to the sunroof frame - but the point is that if a manufacturer wasnted to include an air-sprung seat they'd design the headroom to suit.