Stop and get help
Carbon monoxide can make you sleepy before you realize something is wrong
Carbon monoxide cannot be seen or smelled. If exhaust enters the cabin, occupants can become impaired or unconscious without an obvious warning odor. Never run an engine in a closed garage or enclosed parking structure for sleeping, and do not rely on a slightly open window as protection from exhaust exposure.
Planned car camping and an emergency winter shelter are different situations
If you are planning an overnight stop at a campsite or another legal location, design the night around the expected temperature without depending on continuous engine operation. Choose sleeping insulation, clothing, shade, ventilation, hydration, and weather-appropriate gear before the trip. Battery-powered accessories also need to be planned around their own electrical and fire-safety limits.
A driver stranded in a winter storm may have fewer options. U.S. winter-emergency guidance commonly tells stranded occupants to stay with the vehicle when conditions outside are dangerous, keep the tailpipe clear of snow, and run the engine only periodically for heat while allowing some fresh air. That emergency guidance is not permission to use a continuously idling vehicle as a normal overnight bedroom.
Before an overnight stop, inspect the things that can turn exhaust into a cabin hazard
- Park only where overnight vehicle occupancy is allowed and where the vehicle is in open air rather than a garage or enclosed structure
- Check that the tailpipe is not blocked by snow, mud, vegetation, a curb, cargo, or another obstruction
- Do not park where drifting snow could build around the exhaust while you sleep
- Take abnormal exhaust noise, visible exhaust damage, or exhaust smell in the cabin seriously and have the vehicle inspected
- Do not position the vehicle so another running engine or generator exhaust is directed toward your windows or vents
- Keep combustion heaters, stoves, grills, and generators out of the passenger compartment unless a product and installation are specifically designed and approved for that use
- Have a plan for extreme heat or cold that does not depend on sleeping through hours of engine idling
If severe winter weather strands you in the vehicle
Follow local emergency instructions first. When leaving the vehicle would expose you to worse conditions, focus on visibility, warmth, ventilation, and exhaust safety.
- 01Call or message for help and share your location
Use emergency services, roadside assistance, or a trusted contact as appropriate. Conserve phone power and make the vehicle visible to rescuers.
- 02Inspect and repeatedly recheck the tailpipe
Snow can drift back around the exhaust after you clear it. Do not run the engine if the tailpipe is blocked or if exhaust-system damage is suspected.
- 03Use the engine intermittently, not continuously
When official winter guidance and conditions support doing so, run the engine only long enough to provide necessary heat, then shut it off. Keep a window slightly open as recommended for fresh air, but do not treat that opening as a substitute for a clear exhaust system.
- 04Insulate people, not the exhaust system
Use dry clothing, blankets, sleeping bags, and shared body heat. Keep snow, fabric, plastic, and other material away from the tailpipe and hot exhaust components.
Three overnight plans, three different risk levels
This avoids continuous engine exhaust exposure, but you still need ventilation, temperature awareness, legal parking, and battery planning.
Keep the tailpipe clear, use the engine only periodically, and follow emergency guidance for ventilation and visibility.
A cracked window cannot guarantee that exhaust will stay out of the cabin. Enclosed spaces, blocked exhaust, snow, wind, or exhaust damage can make continuous idling dangerous.