We're about to experience overnight low temps in the teens and daily highs in the 20s. My car is 8 years old and though it has relatively low miles (60k), I'm increasingly mindful of increasing odds of breakdown. If the heater were not functioning, even an hour or two inside the Beltway waiting for a tow truck could become uncomfortable in such cold.

So I put more cold weather gear in the car (an SUV). The car inventory now includes:

fleece hats/neck gaiters/fleece sleeping bag liner (2)
down booties + down mittens
Smartwool socks
chemical warmers (I buy boxes of them from Costco)
Gore-tex hiking boots + Gore-tex gaiters + rain pants


For longer periods and periodic outdoor activities, I have in there:

long underwear
JetBoil
Cup 'o Soup packets, tea bags, cocoa, snacks (+ water, of course)

And emergency gear, incuding fire-making (lighters, matches, firesteel, beeswax candles, fatwood).

I have a 48-gallon Rubbermaid Action-Packer for storing this stuff in the car so the list goes on....

Are you ready to spend a few hours, or more, in the car on a bitter cold day?

We've had other threads on the subject of car survival but it is a discussion worth repeating and usually instructive.

The answer to your question 'Are you ready to spend a few hours, or more, in the car on a bitter cold day?' is 'yes'.
I put a double duvet in the boot last week. Costs less than £20 and all the things you've listed together won't make as big a difference.
qjs

If you have to walk out, a pair of used Sorel boots (packs) are great

What's the duvet made of? Down-filled?


.

Besides all the great gear you always carry, do your Element a favor and perform maintenance before it's due. My "more than 8 year old" Ford started overheating and when checked out the radiator was 90% blocked -- the cost was a new radiator core.

Most all of the things that can go wrong have been replaced with new from the rear axle to the A/C. The serial number is old but the body is solid and everything that makes it move has been replaced. I'm so far ahead on $$ with this truck I try to replace stuff before it breaks. In most cases the cost of a tow or down-time car rental would exceed the cost of early replacement.

To answer your question though, yes, when I leave SOCAL or go anywhere of increased elevation like the mountain passes in southern Oregon (way outside SOCAL), I have a winter kit duffel bag that goes along for the ride which contains:
Winter parka
Smartwool long u/w
Wool & Fleece sweaters
Nylon outer pants
Couple pair of Smartwool socks and sock liners
Boots.
A couple different beanies, wool & fleece
Wool & fleece blankets
MSR MicroRocket
Canned food & water are carried separately.

That's a partial list and I usually dress for the climate I'm in so the list of what's in the duffel closely matches what I'll be wearing as I drive.

I'll be fine, mostly because I'm fairly sure the truck will not break down. There's always the chance of a random accident though and the saying S**t happens still applies.

I tend to also think along the lines of gearing up to get help (AAA service, cell phone, cell phone power cord, watching cell phone battery levels, PLB, ...) and to be noticeable (large orange trash bags can be hung out a window and/or cut lengthwise and run over the roof from door to door for better aerial views.

My father used to buy brightly colored cars for visibility issues.

BTW, I carry a sleeping bag rather than lots of clothing, though I try to dress for the weather - under the assumption I'll need to spend some time outdoors - rather than just running from car to door.

I'm a long time DC area resident (since ummmh, 1966), and have been more or less trapped by DC winter weather four times. Once for 12 or so hours, once overnight (I walked into a motel and asked for a room---and got it!)

The key thing I see missing is a down (or some modern fiber filled) sleeping bag. I see you have the liners, but don't know how warm they will keep you on a really bad night. You may need to stay in your car a long time. Your preps seem fine for a few hours, but you need to sleep also. And I worry that you might be too cold with what you have. A warm sleeping bag and protection from wind/cold/rain/snow in the car can make things much more comfortable. (note: I do not trust "warmers" to work when you need them.)

In all instances, it was NOT the ability of my car or me to deal with the snow and ice on the road. It was the total stoppage of all traffic on the road (I495 ((aka the Beltway)), Rt. 7 in Virginia, I270 in Maryland and 16th Street in DC) that stopped me.

So, my philosophy is be prepared to sleep in your car, totally passive (no external heat), and be comfortable and safe ---doors locked, and stay warm in good quality sleeping bag.

Winter parka and sleeping bag. (maybe 2 sleeping bags)
Insulated pad or layer to keep from losing heat thru compressed sleeping bag material while lying down.

I chose to let myself get snowed in at 11,000' while on a Sept 4WD trip. Basically slept out the storm in my Jeep.

When well equipped there's nothing to fear but fear itself.
(But that sure expanded my personal boundaries!)

Getting the interior de-iced so I could drive out required direct sunshine and time. No way was interior heat going to thaw everything that needed to be thawed.

I've got a complete set of dry clothes, additional wool socks, spare boots, spare outerwear (including hat and gloves), and an AMK bivvy. I have a sleeping bag I can throw in the trunk, but I've got so much stuff in there right now the sleeping bag would take up too much room.

What...again?

In short, more or less. There's only so much space I can afford. Besides the few things already mentioned I got one hell of a trauma kit, and plastic drum liners, tape and para cord just in case I have to cover a broken window first. Don't assume you won't be stranded after an accident where you may have to patch a window or two before trying to keep the heat in your vehicle. While offroading, I managed to put a stray limb thru a side window TWICE if you can believe it.( I know, I'm an idiot)
Fortunately I didn't have to spend those nights in my truck, because it would have really sucked with the wind howling in through a window with no way to patch it up.