> I mean, think of all the wasted space and weight having 8 exit doors on a airplane; they don't crash often

And if we had all doors except one passenger seat, it might be even safer.

We neither optimize for absolute highest survival rate nor for absolute highest convenience/efficiency.

The question is-- how much does the second staircase improve survival? Is it the most economic way to get that survival difference?

Most residential detached multi story houses only have one staircase. If government forced me to give up one bedroom and build an extra staircase, so that I have a slightly higher chance of survival of a very unlikely event, I’d be fucking pissed.

I don't think we are talking about modifing existing buildings or small homes, they are talking towers and large units - a lot of places still count jumping out a residential second floor as an exit, so you'd probably be fine.

Being on the 7th story is very different from being on the 2nd story. If the staircase was to catch fire right now it'd be like a 6 meter jump down the window, maybe less if I manage to lower myself by hanging off the edge. I can land on my legs and I'd risk breaking an ankle or something like that at worst, not ideal but I wouldn't burn to death.

You can get out of 2nd and 3rd story windows relatively safely.

In that case, I advocate for single floor only buildings. At least, if higher survival rate is always paramount.

> think of all the wasted space and weight having 8 exit doors on a airplane

If we could choose to fly on the same plane with 4 doors that would give us more legroom and get us to our destination in less time, I believe a lot of us would make that choice.

Eh? More legroom? Leg room is determined by the airline, not the plane.

If there were fewer doors there would me more seats, and the weight of the seat, passenger, and luggage would far outweigh the weight saving on the door.

And no, you ain't getting more legroom.

Can you elaborate how having more legroom and less doors makes a aircraft go faster?

An airplane with four doors instead of eight would weigh less so the plane may fly a little faster. Legroom shouldn't affect the speed.

I don’t think weight affects cruise speeds a whole lot, as I understand.

At least, not enough to make your flight measurably shorter.

https://aviation.stackexchange.com/questions/47369/how-is-th...

No, the limit of airplane speed is the speed of sound, as you get very close to that aerodynamics changes greatly. While you can make a plane go faster it is rarely done.

So will an airplane with 5% less luggage or fuel. Go figure.

A giant heavy emergency ballistic reserve parachute system (currently used on smaller planes) is a much better analogy than 8 doors, which don't change the equation that much. Let's waste 20% more fuel to be able to recover from the rare all engine failure.