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Comment by gpm | Hacker News Reader

My instinct is to say buses, and don't wait too long. Let's do some math:

Edit: Corrected math. Thanks!

You can easily fit 20 people/bus. So that's 5,000 bus rides. 2000 busses/hour/lane is a reasonable estimate. They had a 4 lane road, 2 lanes in each direction, so 4000 buses per hour. Divide capacity by 2 to account for inefficiency and round up to get to 3 hours

That's a lot of busses, but not an unreasonable number.

To hit those numbers you have to be forcing people to evacuate by bus. If they try and take a car you need to stop them before they jam up the road. American's aren't going to take that easily. Of course you can encourage them to evacuate by car before you start the mandatory by bus evacuation. It's not like forest fires come with 0 warning.

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Excellent to have some calculated numbers!

Two thoughts:

1) Possibly the road could be rearranged to allow travel only in one direction, freeing up at least 1 extra lane?

2) It might be possible to get some of the bigger 50 or 80 capacity transit buses, or some large school buses? One article I found suggested California had in excess of 20,000 school buses, although I'm still looking for a reliable source to back that up.

1) Possible, but you've got significant traffic in both directions. You need to get bus's in as well as out.

2) Absolutely. And really you could probably stuff 80 people into your a bus in an emergency. But you're going to have a real problem organizing people onto buses so I worry that in reality you'd be running many well below peak capacity.

We don't have that many spare buses close enough to any city that would have to be evacuated. Paradise had only a few hours warning. That's just not enough time to gather resources from outside the immediate area.

Paradise in particular had shockingly little warning. It's hard to imagine coordinating any substantial response in time. Still, I'd like to think about what the best evacuation we could do in general even if we can manage to fix this case (The population was also on 25,000 instead of 100,000).

I'm not from California, I'm from Toronto, and to make life easy on myself I'm going to use Toronto numbers. Here the primary public transit operator has (as of 2010, I doubt it's changed that much) about 2000 buses. That's obviously not all of the buses in the city, there are school buses, private charter buses, etc. But it's probably over half.

If we can get the round trip time down to an hour, we can saturate this road. Obviously the response time (to when we start evacuating people) is no better than the travel distance from Toronto to a location we need to evacuate. If we had plans in place to react to these sorts of situations I imagine we could make in no more than an hour or two more than that.

(This also cripples Toronto's public transit, but that's probably acceptable in a emergency).

A round trip time of an hour, including loading and unloading, isn't going to get anyone out of range of a hurricane, fire, or serious flood. The trip times for buses would be several hours at a minimum.

I mean, I left lots of room in my estimate for a reason. But I think you might underestimate how fast you can go on a police controlled highway with only 1 exit and 1 small region of entrances.

You can easily fit 111 people per bus. That makes 901 bus rides. 1000 buses/hour is a reasonable estimate. You can evacuate the city in just one hour if you allow standees during evacuation.

Shouldn't it be 5000 bus rides? 100000/20 = 5000 so <3h and you're done assuming you got enough buses.

Yes... oops.

I thought those numbers seemed high.

Where on earth do these busses come from? Do you propose we should be ready to produce an army of busses anywhere in the US at a moment's notice?

Anywhere with a reasonably anticipated need to evacuate, yeah.

In other words, this falls flat as "reasonably anticipated" gets shot down by cost.

Human life is generally worth more than the corresponding proportion of a bus.

Correct. This is, however, a sentiment which is only expressed during a catastrophe. Give it a few weeks, and see the bean-counters deny this again.

Public transit systems, school systems.

There should basically already be an army of buses in every big city.

Typical bus holds 50 people

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