Too much of me in this thread, so I will skimg through what might be scavenged in my categories of First Aid, Shelter, Fire, Water, Food, Navigation, Light, Signaling, Self-protection, Hygiene, and Morale.

First aid: relatively straight stiff parts such as window mechanism rods for splints and braces; wires and fabric to secure splints, braces, and dressing;, small sheet metal parts ground sharp to cut or shave whatever must be cut or shaved; light sheet metal bent to use as forceps / tweezers; springs straightened to use as needles / awls and small sections used as clamps for wound-closing and bandage-holding; heat from near but not over fuel-based fire to "sterilize;" "sterilized" sheets of seat foam as dressings / bandages; one or more mirrors to give yourself the once-over - especially in areas not otherwise visually available to the normal person for injuries, bites, tick removal, etcetera; and longer metal pieces padded with seat or other insulation as crutches.

Shelter: , except to note environmental resources like trees suggest heavier sharpened metal be used as an axe or ground against frame members or rocks into crude toothed saws.

Fire: Starters would include the lighter, spark from wires connected to the battery, any traffic flares, and steel parts which may prove to generate sparks from rocks in the environment. Fuel might include: any rubber, such as weather stripping around windows, doors, trunk, and hood; seat and headliner fabrics and padding; and, very carefully, any remaining gasoline or diesel.

Water: Already addressed as a Rule of Threes item.

Food: Already addressed as a Rule of Threes item.

Navigation: There may be a useable standard or electic compass onboard. whether or not there is a working clock onboard, you can use any straight rod-like item to set up a sundial to tell time and another placed in the center of the "dial" to do the halfway-between-the-center-rod-shadow-on-the-time-and-12 noon is north [in the northern hemisphere] trick. You may also be able to use a magnet, say from the vehicles speakers, to magnitize a light needle-like piece of steel or iron, which will align itself north-to-south when you float on the surface tension of a liquid [it can be fiddily to make this work]. Strips of any material can make trail markers, especially if brightly colored or metallic.

Light: The battery powered lights will last for a while. If you can remove the battery and wire up one or more of the smaller 12-volt brake or tail lights the power should last longer and have some portability. Wrapping material around a longish metallic piece and soaking it in fuel can make a crude torch. Filling a metallic container with soil and soaking the soil in fuel may be used in the same way.

Signalling: Obviously, light can be used, smoky fire can be used, metallic fabric and mirrors can be used to "flash," metalic and brightly colored fabric can be fixed to anything tall and bare as signal flags, and large X's, perhaps three in a row, created out of material or scrapped into the ground can create signals highly visible from a distance, including the air. Any traffic flares can be great signal, especially at night. And by all means use Onstar if available and working.

Self-protection: The creation of spears, knives, slings, slingshots, and possible bow-and-arrow have previously been mentioned. Alarm-sounding stone-in-a-metal-container or noisy wind-chime-type arrays can be hung up attached to trupwires wherever you think best. Many smaller vehicle pieces may be used as missiles. Any edged or blunt tools you have created can serve a defensive purpose.

Hygiene: Mirrors can play their customary roles. Water acquisition, etcetera, has been addressed as a Rule of Threes item. Dedicated persons can sharpen metal razor sharp, and abrade crude combs into being from metal or plastic. Coarse fabrics could be used as rough scrub brushes, but not I think toothbrushes. A plastic sliver could be abraded and smoothed to form a toothpick or fingernail cleaner. You could fashion a Roman / Greek style strigil [a small dulled crescent-shaped tool] to remove dirt along with sweat by scraping them off.

Morale: Game pieces for playing chess, checkers, cards, and dice can be fashioned over time from smaller pieces of fabric, plastic, or metal. Loose nuts, screws, and whatever can act as objects for which you are gambling. Crude drums and other noise-makers could be made, and something approaching music might be created. Throwing games using scavanged or crafted items also come to mind.

These are just some off-the-top ideas. I look forward to whatever the brain trust chooses to add.