You raise some good points (I Hope) I may be able to provide some input...
Ok, for starters, this is about survival and Shelter In Place (SIP) Or Alternative Location To Rendezvous (ALTR)
Being a Military brat, my Father once tried to teach us a thing or two about surviving and getting the h*ll out of there when the time comes - Quickly and effectively - as efficiently as possible.
This might bring up sore wounds or re-open old ones but no matter what - LT brings up a point of being able to get from Point A to Point B when you don't have the luxury of having a direction or route that is a straight line.
Best to plan ahead, and also consider your immediate needs and taking hits on the ability to make it there with what you have in the tank and on the ground you can take with you.
Most people don't see this, because we've lived in peacetime for nearly +40 years without some form of "Cold war" and having to watch your back because you don't know whom you can trust. It's harder to think life can be different - be thankful for what you have right now.
Some feel their SUV can be a SIP - they live in it and can call it home - but one thing is not considered, it was very prevalent in Texas just this past winter.
When you lose power - where is your next best place to shelter? Vehicles can only take in so much and have little and if any, amenities' for comfort just sitting there - you can ride out a day or two even take short trips to relieve yourselves. But you also have a requirement - Fuel - just like our own selves need nourishment - so does your means to get you out of there if the short term turns into a Long-term dislocation - relocation, event. So the ALTR approach with family, friends or Relatives takes precedence here.
Ok, there's one aspect, but how much can one tankful take you?
Many think oh, I just take my Gas mileage and multiply it by the number of Gallons my tank is...
Yes, to a point - and if you remember, when you have such an emergency, remember there are others that are facing this very same predicament as you - some re-route to refuel - you wait in line - sometimes a long time if you can even route there - meanwhile that emergency is getting more critical and closer.
Others may try to take a shortcut - remember that many others are looking at their Phones for that very same information.
Which not only do they route out differently, but you have to consider other conditions you'll be in...
How big is your motor? Are you an automatic or manual? Did you bring a gas can of at least a 5 gallon capacity with you?
Why does that matter?
If you run a V8 - or L-6 you might run out of fuel before you reach your checkpoint - many roads are simple two lane and will be lined with traffic heading in one direction, out of there, right along with you.
So any form of having to stop - a breakdown, accident or any sort of delay, can and will, take away your ability to drive at the most efficient speed possible - affecting your Gas mileage. You will lose mileage, especially true in automatics - Manuals can do better when it come to this because of the type of gear you can select gives you better creep and acceleration choices as automatics will still slip/spin up and down - against a torque converter that can't "lockup" until highway speeds are attained can waste a lot of fuel trying to pull the vehicle and all it's contents along with it at low speed in stop - start traffic.
Your vehicles engines' size, at idle, works against you in these cases. Bigger larger motors consume far more fuel and work more like an air pump wasting energy it can use otherwise, convert into motion to get you farther ahead. Having the engine Idle is your worst enemy when it comes to saving fuel to cross the finish line - Ford has done something similar to the cut-off and start - this helps but does take away some comfort features unless you override the feature.
We won't talk about heat just yet, but if you own electric - well, good luck and extension cords won't work - you won't have many places to plug in and wait along the way...
- Hope it's not too cold - the only thing you've got in such a vehicle is something that operates a lot like a hair dryer - and it uses the very same batteries' you're using to get out of there.
So what
@LionsTooth can teach us, is something we all need to be aware of; because of changes in both the environment and in our country's societal-approach and governmental agencies are taking us into - you may not like the results.
I don't want to turn this into _ "I bought this for this reason". No, I bought the Fiesta because of PREVIOUS experiences with other vehicles I've owned - I've made a "Best choice" selection based upon my current needs and yes, it does include, if and when the future, knowing what I know from the past - if that has taught us anything - buying big can be a costly mistake.