Can You Sleep with the Car On? Think Twice and Learn Why

During a long road trip, drowsiness sets in at night after hours of driving. You pull over at a rest area to catch some shut-eye, but you want to keep the car running for heat, air conditioning, or even just to charge your phone. The question is, can you sleep with the car on?

Quick Answer: Sleeping with the car on is possible, but it’s important to consider factors like safety, legality, and fuel consumption. Ultimately, it’s not recommended due to the potential risk of carbon monoxide poisoning, violating local laws, and draining your gas tank.

Safety Concerns

There are several safety concerns associated with sleeping in your car with the engine running.

Carbon Monoxide Poisoning

Using your car while sleeping poses a carbon monoxide (CO) poisoning risk. CO, a lethal colorless and odorless gas, accumulates when inhaled in large quantities. Car engines create CO as a byproduct, and dangerous levels of CO may build up if parked in enclosed or poorly ventilated areas.

Symptoms of CO poisoning resemble fatigue or sleepiness, including headache, dizziness, nausea, and confusion. Prolonged exposure to high CO levels can cause unconsciousness and death. To avoid this danger, turn off the car engine before sleeping.

Vehicle Theft

When you leave your car running unattended, it can attract potential thieves. You might feel safe sleeping in the car, but a thief can easily break in to steal your belongings or even the vehicle, stranding you.

Fire Hazard

In a rare case, a running car can cause a fire hazard due to fuel leaks or electrical issues. Turning off the engine before sleeping reduces fire risk.

Legal Considerations

Aside from safety concerns, legal considerations also exist when sleeping in your car.

Idling Laws

In many jurisdictions, idling your car for extended periods is illegal. These laws aim to reduce air pollution and fuel consumption. Be aware of local rules to avoid fines or penalties.

Sleeping in Public Spaces

Some places also prohibit sleeping in your car in public areas like rest stops, parking lots, or road sides. These laws are often in place for safety reasons or to prevent individuals from living in their vehicles. Make sure to check local regulations to avoid any legal trouble.

Fuel Consumption

In addition to safety and legal concerns, there are also significant fuel consumption and environmental impacts associated with sleeping in your car with the engine running.

Draining Your Gas Tank

Running your car while sleeping significantly drains your gas tank .The make and model affect how much gas it consumes, ranging from 0.5 to 3 gallons per hour while idling. Over several hours, this can empty your tank, leaving you without fuel for your journey.

Impact on the Environment

The environmental impact of idling your car for hours on end is another reason to avoid sleeping with the car on. Burning gasoline creates CO2 and other pollutants that cause climate change and bad air quality.

Alternatives to Sleeping with the Car On

Instead of sleeping with your car on, consider these safer and more fuel-efficient alternatives:

Bundle Up or Use Battery-Powered Fans

If you’re concerned about staying warm or cool while you sleep, consider bundling up in blankets or using battery-powered fans to maintain a comfortable temperature. These options are more energy-efficient and pose no risk of CO poisoning.

Invest in a Portable Power Bank

If you need to charge your phone or other devices while you sleep, get a portable power bank. This way, you can keep your gadgets charged without running your car engine.

Also, a power bank can be useful during emergencies or when there is no electrical outlet nearby.

Choose a Safe and Legal Place to Sleep

When planning your road trip, research rest areas, campgrounds, or other designated places where you can legally and safely park your car and sleep overnight. Many campgrounds even offer amenities like showers and restrooms, making them a more comfortable option than just pulling over at a random rest stop.

Use a Vehicle with a Built-In Sleeping Space

If you’re frequently sleeping in your car during travel, consider buying a camper van or an RV with an additional sleeping area.

These vehicles are designed for overnight stays and often come equipped with proper ventilation and insulation, making them a safer and more comfortable option for catching some Z’s on the go.

Precautions for Sleeping in Your Car

If you absolutely must sleep in your car with the engine running, take these precautions to minimize the risks:

Park in a Well-Ventilated Area

Choose a parking spot in an open, well-ventilated area to reduce the risk of CO buildup. Avoid parking in enclosed spaces, like garages or against walls, as this can trap the gas and increase the risk of poisoning.

Crack the Windows

To further improve ventilation, crack your windows open slightly to allow fresh air to circulate. This can help prevent CO from accumulating inside your car.

Use a CO Detector

Buying a portable carbon monoxide detector can save your life if you intend to sleep in your car frequently. These devices can alert you to dangerous levels of CO, giving you time to take action and get to safety.

Set an Alarm

To reduce idling time, set an alarm for your desired wake-up time. This way, you’ll be less likely to oversleep and waste gas or risk CO poisoning.

Lock Your Doors

Remember to lock your car doors while you sleep to prevent theft or unwanted intruders.


Ah, the lure of a cozy snooze in your car with the engine running, providing warmth or cool air, and a charged phone. Enticing, isn’t it? But, as you’ve discovered, this seemingly harmless act can come with a hefty price tag – from carbon monoxide poisoning to legal troubles, and even environmental impact. 

So, dear reader, resist the temptation, and instead, embrace safer, more eco-friendly alternatives like bundling up or using portable power banks. 

Plan your road trips with designated sleeping spots in mind and consider investing in a vehicle designed for overnight stays. If you must sleep in your car with the engine running, take precautions like parking in well-ventilated areas and using a CO detector.

Sleep tight and travel smart!

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