Question
I went to a party, and rather than drive drunk, I just climbed into the back seat of my car and had a snooze. When I told my mom, she asked if I had the windows up and freaked out when I said yes. Her worry is that I could have suffocated. Is it really dangerous to sleep in a car with the windows rolled up?
The Answer
Cars are purposefully designed not to be airtight, so suffocation due to lack of air in a car when the windows are rolled up is not something you have to be too worried about. Certainly, sleeping in the back of your car instead of driving drunk, which can have all sorts of legal and health ramifications, was the better choice. Had you gotten pulled over, you might have been cited with a DUI and ended up in jail.
That said, there are safety considerations to factor in before choosing to sleep inside a car:
Carbon monoxide poisoning: Under no circumstances should you sleep in your car while the engine is running regardless of your parked location. Prolonged exposure from an idling car could result in carbon monoxide poisoning.
Heat: If it is hot out, think twice before falling asleep in your vehicle. You can easily overheat your body to the point of heat stroke. Rolling the windows down and parking in a shaded spot can help but when in doubt, be cautious if the temperature gets too high. Sleeping with the AC running may be tempting, but that should also be avoided due to the risk of carbon monoxide poisoning from an idle car running while you sleep.
Cold: The opposite is also true. If it is too cold outside, sleeping in the car can cause hypothermia. Depending on the weather conditions, your car could also become snowed in if fresh snow accumulates while you’re asleep and you could then end up stuck in the car.
Safety: If you’re going to sleep in your car (with the engine off) and the temperature is reasonable, you also need to factor in safety elements. Pick a location that is ideally busy, well-lit, and designed for sleeping (like a rest area or truck stop). It would be best if you also locked your doors.
Legality: It’s also important to know whether you’re even allowed to sleep in your car at that specific location. You cannot just pull into any random parking lot or residential street and sleep in your car. Oftentimes, businesses will have signs posted about the rules for sleeping in cars in their parking lots.
Privacy: Another consideration is privacy while you sleep, depending on whether you plan to sleep through the night. If your windows are not tinted, you may want some windshield and window coverings to give you privacy while you sleep.
Kevin Berry is the Senior Director of Content at Jerry and has been working in the digital content space since 2011 across the car insurance/repair, personal finance, travel and sports industries. Prior to Jerry, Kevin was a content team lead at NerdWallet overseeing the Multimedia Production and Travel Rewards teams. Previously, he worked for NBC Sports, Comcast Cable and Nike. He has a Master`s Degree from Arkansas State and a Bachelor`s from Oregon State University.
Giselle Gomez is an editor with over a decade of experience editing content across personal finance, education, travel, and sports. In editing for Jerry, Giselle’s focus is on making sure content is consumer and SEO-friendly and helping readers understand all things car ownership. In prior roles, she worked as a content strategist, syndication editor, and writer. Her work is featured in AP, NerdWallet.com, BestColleges.com, and more. Giselle holds a master’s degree from Arizona State University.
