You may not get a choice of when you need to survive.
If you are going out on a hiking trip, camping, or other sporting endeavors not involving vehicles, then you are stuck with what is provided and what you can carry. When you go out with professionals, do what they tell you to do as they are being paid to keep you alive: you paid them, that is your investment, don't squander it as your life is on the line.
From the recent season of Deadliest Catch we saw what happens when the Katmai went down: the survivors were Captain, Deck Boss, and two greenhorns. Another experienced crewman and another greenhorn also made it to the one craft that would allow people to survive, but the greenhorn was injured and the other crewman was trying to secure the life raft and both were taken when a huge wave swamped the inflatable raft and they were swept into the ice cold waters of the Bering Sea. They could be heard in the distance, but leaving the one, sole, means of safety to get them during a storm with hurricane force winds and 40' waves is a non-starter. That was a ship and crew that was PREPARED for the worst arctic storms of the Bering Sea. Four men of eleven survived.
Those two greenhorns survived because they followed orders. The two lost from the life raft were taken by the force of nature, herself, and she is not a loving mother.
With any luck YOU will not decide to become a crew member on a ship in the Bering Sea during winter.
I do admire the men who go fishing in all waters, as the seas and Great Lakes are neither kind nor unkind, but always fierce no matter how placid the snorkeling in the Bahamas or the quick dip at Crystal Beach. If it isn't the wind then its the sun. If its not the doldrums without wind then its the waves. The safest body of water is a cup of lukecold coffee that can't scald you... just don't swallow it into your lungs and you will be fine.
Unfortunately when you need to survive usually is not when you would expected: that is why it is called 'surviving' and not 'camping', although the latter can quickly turn to the former if you forget just where you are at in the wilds. It is interesting that one of the problem cited by Les Stroud, going off into the most desolate regions of the planet during some of its nastiest times of year, is that he has problems getting AWAY from people. Still the circumstances can happen to you any time you are out doing something else. And that point is beyond your reckoning, although it usually happens when you would least want it to.
Getting out of a sinking car requires that you actually keep your cool. Panic will kill you.
Your air time is limited, and in a sinking car with cold water coming up around your legs, you have little time left and yet must be calm at all times, no matter who else is with you, or else they will be dead with you, too. Mythbusters did an episode on what actually happens when a car sinks, and the very basics of water pressure, air pressure and the force exerted by each is what you would expect: you can only open a car door when there is little inward pressure from the outside or equal pressure on both sides of the door. If you wait until your head is submerged you can open the car door, unbuckle your belt and calmly float to the surface. Now if the surface is frozen over you need to find the hole where your car went through and get out.
If you cannot wait due to the water depth, say if your car fell out of a ferry crossing a deep body of water or something equal, like getting put into the Hudson River, then you need a hard, pointed metal object to break the safety glass of the car. If you have unbuckled before that and got the straps out of the way, there is a good chance you will get pushed out with the air pocket. If not then you must keep your head about you and wait for the buckle to be submerged to open it... or use the safety sawing end of something like the Life Hammer, to get yourself out. Then no matter what you had in your vehicle, it is what you carry ON YOU that you MUST rely upon. And you are wet and cold. And so is your stuff.
That is probably the worst that will happen to you and survival is then a matter of season, getting out of the water, taking your clothes off to dry and keeping warm. That is all on your person or easily with you at all times, right?
In the James Burke scenario of 'what if the power goes off for good?' idea your vehicle is not only something that can get you into danger, but get you out of it, unless the circumstances are very dire, indeed. And yet what you need in the vehicle is going to depend on what you think the most likely thing to happen will be. If a flat tire skidding you off the road and out of sight and keeping the vehicle more or less intact is the situation you think most likely, then you plan for that. If getting stuck in a 10' snow drift with 60 mph winds and driving snow is what you expect, then you need a different set of essentials. If you are purposefully leaving the collapse of civilization, then you have a third and very different objective, and yet it overlaps the 'survival with your car disabled' concept.
Still some essentials or equivalents are necessary and must be readily available from the main compartment of your vehicle. It really doesn't help to have stuff in your trunk if that is the part that is stuck in a snow drift... or the main part of your car stuck in a snow drift and you can't get to your emergency equipment. If its in the bed of your truck, having stuff secured in it is second nature, and the rear window might help you get to the material there. In some hatchbacks you have limited space and will need to look at a container accessible in the main compartment of the vehicle. 'Handy items' are not 'handy' if you can't get to them easily.
In Buffalo a sleeping bag, an old Coleman's or milsurp (military surplus), is good enough along with a second blanket, usually wool. In more moderate climate you can get away with space age 'survival' blankets, although I suggest two per person so there is some ground cover along with a blanket, or the new emergency sleeping bags purpose made for this of the same material. Casualty blankets are similar, just tougher in construction. Along with that was a first aid kit, which my Buffalo one was a few band-aids, a roll of gauze and a few prep swabs. I would improve on that and there are a number of better solutions from 'first aid kit in a can' to 'SAS first aid kit' to 'first aid kit in a water bottle' to the military personal and squad first aid kits. Any kit should handle the usual scrapes and cuts of outdoor survival for all in the vehicle.
So we now have some basics forming up.
A Life Hammer or equivalent and there are many objects that do this, this is not a recommendation to part but category.
First aid kit from minimal to maximal, but must be good enough for a few days for all expected passengers of a vehicle. If you are going to take a family, it MUST meet the needs of an expected, survivable accident for all aboard. Keep any pets in mind, too. Very flexible, but I would base it on terrain and climate, as well as expected passenger load.
Next I would add either one large quick clot bandage pack or the assorted small pack: if you need to stop a large wound, this is the stuff you want and is near magical at what it does. That you should be able to scrimp on at one-half the passenger load, so the multi-pack is better for families. In any event at least ONE of these.
Emergency rain gear. Never fails that your time for survival happens in the rain and you just went out blithely ignoring it. Your choices range from minimal (emergency rain poncho, blaze orange) to maximal (milsurp from various countries). Note that an emergency set of ponchos isn't so good at forming a temporary shelter while two milsurp ones ARE. Amazing, no? Its like they planned on that or something. One per passenger.
Cold weather gear. If you have milsurp ponchos, get the inserts for them for cold weather. Otherwise you are looking at real blankets/jackets/leggings/socks/etc. If you expect cold weather and wear for it, then you are just down to some extras to your regular coat/parka/outdoor arrangement. If you normally favor thin to no legging arrangements, then supplement that in your vehicle with what you really need to hike out in the cold. Pretty is not necessary, functional is. Better to look funny and alive, rather than good looking and frozen stiff. One per passenger.
Emergency tent. Cheap and blaze orange runs about $5. Two milsurp rain ponchos and nylon cord, about $15. The first is your glove compartment, the latter a larger container. With one emergency tent, two milsurp ponchos and emergency blanket you now have an emergency camping arrangement, with ground cloth. One emergency tent per two expected passengers.
Emergency food. USCG/SOLAS 3600 calorie brick, that breaks down into 9 x 400 calorie cubes, and there are 2400 calorie ones in the same arrangement of 9 sub-squares. Shelf life, 5 years. A bit much for the glove compartment and figure on the maximal survival needs for that brick when sizing numbering what you will buy. MREs are also a good option if you have the space for them. The main idea is to pack in objects that can either fit in existing space or a small storage container (say a half-sized foot locker or something that can relatively anonymous and not an invitation to having the vehicle broken into. Minimal human survival is 1200 cals/person/day doing nothing much at human average. Normal hard working day is two to three times that. Survival can burn over 7,000 calories per day per person. You can do without much food for a week or so, but never expect that you will have an emergency where a week is the minimal time to survive... and that week is without doing much of anything. Suddenly a 3600 calorie brick doesn't look to be that much.
Emergency water. First are water packets USCG/SOLAS approved. Next are water treatment tablets. After that a water treatment system that will kill all bacteria and viruses. Price goes up from pennies to dollars to tens of dollars. A water bottle is REALLY handy if you go beyond packets. Canteens are even better. How much? In normal conditions you might go through a quart a day, doing nothing. In my desert excursions I carried a 5 quart canteen and another quart in water bottles and often found myself out of water after 6 hours. Hiking during the day in the desert has a high bodily cost. Hiking alone in temperate climates that 5 quart canteen lasted from dawn to dusk hiking. One quart is minimal per person per day.
Emergency heating. An Esbit stove, also known as the German Army personal field stove, uses any solid fuel but prefers the hexamine tablets. Alcohol stoves as part of mess kits (usually Swedish or Swiss if memory serves) are also a good idea, and they require an alcohol bottle to be with you but is part of a complete mess kit, and the military ones from Sweden or Switzerland make them to fit in very little space. Also waterproof, burn underwater matches are small, give a few seconds of flame even in a hurricane, and easy to pack away. Strike anywhere matches are also fine: keep them dry via a container. Striking devices will get you more sparks, last longer and you don't have to worry about them getting wet, either. At least one of these per group should be minimal and one per person much safer for all concerned, and don't forget things like butane cigarette lighters, either.
Mess kit. Ever so handy if you think you will need it, and a great place to store little items in case you think you don't. Really, a lot of small items (water purification tablets, extra stove fuel, even parts of MREs) can go into a mess kit. At the very least they make a great sound signaling device by banging on them! Ersatz mirror if you rub them up a bit. As mentioned above in heating, you can get good milsurp that are a complete small stove and heating cup arrangement, along with fuel. Esbit or Commando Stove with flatter, more traditional US messkits works fine, too. One per person. Don't forget utensils.
Cord. Nylon, cheap, 100'. Keep in original packing.
Multi-tool. Many choices from Leatherman to Swiss Army to Gerber to the little credit card one. If you already carry one, then no need to have one in your vehicle save as back-up. One per group is minimal, and one per person is best.
Signaling devices. Reflectors for relatively even surface roads, put down and make sure they stay put. Flares, USCG/SOLAS are good as are the Cyalume chemical ones used in so many parties. Cheap, too. On the serious side beyond the hand helds/stick on the road flares, are wind-up flashlights/strobes some with batteries, some without, all must take hand cranking as a capability so you can power it up if everything else fails. Really you need some hand signaling devices if you are by the side of the road. After that you are in serious attention getting areas where a hand flare may not get you seen. In daylight that also means a mirror, any size, any type, bigger is better but keep in mind the size constraints of the vehicle. After all of that comes the flare gun, and there are many decent milsurp ones with expensive (but very nice) flares that go very high and you can even get the parachute flare which is a big help in keeping a signal in the air for a longer period of time. A step below that are the USCG/SOLAS ones which are good enough for ship emergencies and signaling. One per group, minimal, and one per person is best.
One large pack to hold all this, or smaller ones to divvy out per person. Things like haversacks, buttpacks, musette bags, bread bags, gas mask bags... all of these have storage for an individual to carry comfortably. If you have few people to pack for, still get smaller satchels/bags even if you invest in a large pack for everything. You can either share the load, or have handy-dandy sub-packs to put stuff into and throw in the larger pack.
For the pure emergency concept all of the high-tech, blaze orange gear, plus food brick, mess kit, first aid kit with quick clot bandage, reflectors, hand-held Cyalumes, multi-tool and a few packets of emergency water or purification tablets/pills, Life Hammer... all of that is glove compartment compatible with some parts suitable for under seat stowage (mess kit, first aid kit), or for mounting next to your seat or in other handy places (Life Hammer, water bottles/canteens with carabiners). Tools can either be kept in purpose made holsters, or lightly oiled, wrapped in cloth, and tossed into a plastic bag for safe keeping. Don't forget that oil part for iron and steel that will just be sitting in your car. Your engine does that naturally as part of what it does.
Moving up to milsurp ponchos, MREs, wind-up signaling device (or similar solar one), flare gun, emergency weather gear (cold weather normally, but your environment may have other requirements), that all goes WITH the true emergency gear as these are extended time necessities for rough terrain.... all of that needs dedicated storage where it is 'handy'. Folks already doing off-roading have most of this, and if you don't off-road and expect that your climate/terrain/circumstances can put you out of touch with the rest of humanity for a few days and your vehicle end up a no-go then you need the extended kit.
That being said if you are waiting FOR rescue and your vehicle CAN be spotted from the air, then stay with the vehicle. Really, it is larger than you are, has a compartment that can be sealed from the elements and your body is a lovely heat source! And that heat is FREE for the effort involved of keeping you alive. Trekking out should be a last resort in an emergency...just keep your ration use low because if your circumstances change and you realize you DO need to hike out, you will need to eat some food and have some water to survive the trek. The rations are necessary to keep your body interested in surviving, stave off the worst of hunger pangs and allow you to remain calm and parcel out your needs. Trekking out puts you into Les Stroud/Bear Grylls territory and you can watch their programs to learn the basics of trekking out. Getting stuck in a ditch off of a main highway is one thing. Your car swept away by a flash flood another. Going off-road by accident and your car and you not visible to anyone, a third. In some place you can go from the first to the second to the third in under five minutes.
Then there is the 'everything has failed and isn't coming back' packing in your car. What you have packed away in the extended emergency concept is very close to this and your vehicle, properly parked out of sight, serves as your first and primary safety device. If you can get it and you to a relatively safe place where you can forage and even scout a bit, you then have some time to see how events play out. There are lots of things you will wish that you had with you that you don't have. But with what you do have, you have the very basics to wait out a few weeks recognizing that you need to recognize how to catch/dress small game and find edible plants/nuts/roots in your area. That requires you to prepare if you are serious about that endeavor, and there is a whole section of books that have been written about this, including Les Stroud's one on living off the grid. Notice that the 'grid' is civilization in the way of electricity, potable water, sewage and trade areas for manufactured goods. If you are that serious then your home is probably off grid already.
Mind you if you are expecting an EMP attack, then your vehicle (unless it was made without ANY computerized components) will be a lovely hunk of metal, rubber, and volatile fluids. If you took the enhanced emergency concept, then you are now in the 'trek out' option by default. And you are 'living off the grid' with no preparation for it, which could be an urban area in the middle of the day. If you are serious (dead serious) about this 'survival after EMP attack' thing, then a nice pre-computerized, pre-mid-1970's vehicle is for you. In Buffalo those used to be known as 'rust buckets' and not expected to do much save be drivable during the winter. Your want or ability to keep one up is up to you. If your legs can last hiking from urban to suburban to rural to wilderness then you only need your stamina and calories to feed it.
For most everyday people this living in non-contact with the grid of technic civilization is a hard one, yet it is but one EMP burst away. Or one very, very nasty solar storm aimed at Rock 3. In the former the Nation has been attacked and been brought low and we might have an ally or two willing to help us. If we don't screw that up, that is. In the latter there is no 'outside rescue' anyone will ever see and the planet is on DIY principles and rebuilding from the ground up as we no longer have the tools to make the tools to make the tools to make the tools to make modern equipment: we have stepped back into the 1950's as the best, most useful, 'high tech' outside hardened electronics in the armed forces.
If you can't Do It Yourself or prove an asset to those who CAN during those times, then you have a survival problem. Getting the skills to be an asset to yourself then makes you an asset to others and is the basis for all civilization. Being civilized is up to you. And, no, the skills for the 'hood in the way of gangsta-anything are NOT survival skills. They are suited to a degraded society that remains technic, by and large, and when the power goes off the drugs dry up, the electricity doesn't make anything work, the music stops, the clean water stops, the sewage stops, and without the necessary skills you will soon be stopped, too. Being a barbarian only goes so far, and with the knowledge and resources held by those who do not place great faith in the nature of man to survive such events, they are prepared to use their Liberty and natural right of self-defense to recreate civilization.
Knowing how to make a spreadsheet is nice, but not a handy survival skill. Flint knapping is a handy survival skill.
Knowing how to operate an MP3 player is nice, but not a handy survival skill. Fishing is a handy survival skill.
The use of indirect tools that have multiple layers of technology between you and the tool usually means the skills to use those things is of relatively little use in a survival situation where there is no 'grid' to attach to.
Thus the things you pack for an emergency will have to stand you in good stead until you get those necessary skills and can find time to hone them while keeping alive.
Would most of our technology succumb to an EMP burst or long solar storm directed at the planet?
A lot would be fried, yes. Even the bursts of nuclear devices in the '40s and '50s saw some equipment problems with lovely vacuum tube technology that is pre-hardened by being vacuum tube technology. The major joke of the 1960's and 1970's was that the USSR, by being backwards on technology, actually had a more survivable infrastructure than the high-tech US for EMP attack. Outside of the early tests and induced ground current events from solar flares, no one really knows what would happen with a properly devised and situated attack or a few days long solar event. This makes your grandparent's household items from the 1920's to 1950's far more useful than your parent's items from the 1960's onwards. Simple mechanical tools not depending on high tech will do well, by and large, while electronics is a spotty gamble. What would the death toll to these sorts of events be?
For the US only a few tens of millions dead for the EMP attack, at worse.
For the rest of the world to have the 'grid' taken off-line on at least a 5 year basis, if not for good?
The planet could sustain 2 billion people quite well before modern high tech, and would continue to do so. Those in the poorest reaches would both have the highest death toll at start and the fastest recovery rate in the long term. A more technic area would have problems that would grow worse as learning that what we knew isn't coming back would only sink in once initial supplies ran out. Then you are in the James Burke area of things.
Mind you, this is not the worst I can think up... this is just the worst survivable event I can see that has a high probability of happening in the extremely short range timeframe. Neither of these are true extinction events. Our species can survive one of those massive events, but that depends on getting off of Rock 3 from the star Sol. There are other things actually as bad or worse than this in store for North America and other parts of the globe. The sort of preparedness I am outlining will serve you well in some of those, too.
If you take the precaution to prepare ahead of time and don't put off to tomorrow what can be done today.
Your vehicle is but a contrivance to ensure that you have extended mobility. When it is no longer mobile, you are down to YOU. Any first object of such mobility should be to get to your next and greatest haven of supplies: your home. With precautions you can get along for awhile with what you have on you and in your vehicle. It is unlikely that any medications you need will survive temperatures inside your vehicle, so you will end up doing without until you reach the next place where you KNOW they are secured, and quickly.
No one will do this for you if things go horribly wrong.
Being out of touch with civilization and waiting for rescue is one thing.
Rescuing civilization requires you to be civilized and survive.
And it does mean thinking about the worst so that you don't worry about it. Some events are out of the hands of any government to protect you from, and are, yet, well known and will happen. No one is looking out for you when they do happen. Stranded by bad luck is one thing. Surviving the forces of nature quite another and skills play a large role in survival. Those that survived the Katmai and knew NOTHING of survival on the Bering Sea followed experience and lucked out. For you this means preparing and not fetishizing over such things.
If they happen you are prepared.
And if they don't you are prepared for less worse things to happen.
If your family is with you, then you lead by example no matter your age.
Think of your destination.
Take what you have that will help you survive to it.
No one can do this for you.
And you will end your worries about it because you have prepared and are confident in yourself.
Even if thrown to chance, you CAN and SHOULD load the dice in your favor.