On the topic of getting stranded in your car, it's pretty easy to suffocate in there. People sit in their cars inside snowdrifts with the engine running to stay warm, not realizing that their tailpipe has clogged up. That forces the carbon monoxide in the exhaust back into the car, where it can quickly fill the relatively small space. Carbon monoxide bonds to hemoglobin in your blood in the spot where oxygen normally hitches a ride, but unlike oxygen the carbon monoxide molecule doesn't get released. As you breath in more carbon monoxide, fewer of your hemoglobin proteins can bind with oxygen and you slowly suffocate. The only consolation is that you'll pass out from lack of oxygen before you realize you're suffocating, so at least it's not painful. On the other hand, carbon monoxide is colorless and odorless, which makes it difficult to know what's happening. If you find yourself getting sleepy while trapped in the car, it's probably carbon monoxide poisoning.