Post-disaster road hazards

01 — Why an officially reopened road is not the same as a safe road

A road being open to traffic confirms it has been inspected enough to allow vehicles through. It does not confirm every section is still structurally sound, since damage can hide beneath standing water or simply have not been found yet.

Driving back into a disaster area, after a hurricane, severe flooding, or another major event, calls for a meaningfully more cautious mindset than ordinary driving, even on roads with no closure signs. Watch specifically for: downed power lines (covered in detail below), washed-out pavement where the road surface itself has eroded or collapsed, debris of all kinds, standing water that may be hiding a deeper hole or a missing section of road beneath its surface, bridge approaches that have been undermined by flooding even when the bridge deck itself looks intact, missing or damaged road signs, and traffic signals that are dark because the power that normally runs them is out.

• Treat every dark traffic signal as an all-way stop, the same standard rule that applies to any unpowered intersection, slowing well in advance and confirming no cross traffic before proceeding.
• Standing water is genuinely the hardest hazard to judge correctly from inside a vehicle, since its surface gives no reliable indication of what is happening to the road beneath it, whether that is simply a few inches of water or a washed-out section deep enough to swallow a wheel or trap a vehicle entirely.
• If a road looks damaged in any way you cannot fully assess, turn around rather than proceeding to find out. A detour costs time. A vehicle stuck in or carried away by a damaged road section costs considerably more, both in immediate danger and in the time it then takes to get help.

02 — A highway breakdown: getting it right in the first 30 seconds

A disabled vehicle on a highway is itself a genuine hazard to other traffic, and the highest-risk moment is often not the breakdown itself but what the occupants do immediately afterward.

Pull as far right as the road allows, ideally fully off the traveled lanes onto a shoulder or breakdown lane, and turn on your hazard flashers immediately. Once stopped, stay inside the vehicle with your seatbelt fastened, particularly at night or in poor visibility, since the inside of the vehicle is meaningfully safer than standing beside a highway with traffic passing at speed.

• If you must exit the vehicle for any reason, exit from the passenger side, away from traffic, never from the driver's door directly into the lane of traffic you just occupied.
• If you have reflective triangles and it is genuinely safe to place them, set them at roughly 10, 100, and 200 feet behind the vehicle. This graduated placement gives approaching drivers progressively earlier warning the farther back they are, rather than a single warning point too close to react to safely.
• Never walk along the highway shoulder toward an exit, and never stand behind your own vehicle attempting to flag down help; both put you directly in the path of a vehicle that fails to see or react to the breakdown in time.

03 — A snowbound running vehicle: how little time matters

A controlled laboratory study found that lethal carbon monoxide levels developed inside a snow-obstructed vehicle in just 2.5 minutes with the windows fully closed, and only one specific intervention brought CO inside the cabin to zero: completely clearing the tailpipe to ground level, not just sweeping snow away from around it.

This deserves direct attention because the commonly repeated advice, "clear the tailpipe and crack a window," significantly understates both how little time is actually available and how thoroughly the tailpipe genuinely needs to be cleared. In the same controlled study, opening a window one inch only extended survival time to roughly 5 minutes, and opening it six inches extended it to roughly 7.5 minutes; cracking a window helps, but the difference it makes is measured in single minutes, not in safety. More strikingly, the study found that even after the area immediately around the tailpipe was swept clear, and even after a full cubic foot of snow was cleared around it, dangerously high CO levels still developed inside the cabin. Only when the tailpipe was completely unobstructed all the way down to ground level did the cabin CO level read zero.

The mechanism explains why partial clearing fails: carbon monoxide is a byproduct of incomplete combustion, present in every running engine's exhaust, and it can seep into the cabin through leaks and cracks in the floorboard, trunk gaps, or the HVAC system whenever the exhaust path is restricted enough to build up backpressure around the tailpipe, even if it is not fully sealed. This is not a rare or unusual event; CDC data attributes roughly 500 unintentional CO poisoning deaths annually in the United States, and a documented blizzard in January 1996 produced 22 reported CO poisoning cases in New York City alone over two days, almost entirely from people sitting in idling vehicles with snow-blocked exhaust pipes, disproportionately affecting children and elderly people.

04 — A downed power line on your vehicle: the procedure that has saved lives, and the mistake that has cost them

A vehicle's metal frame, while you remain fully inside it, generally directs electrical current around the cabin and into the ground rather than through you. The moment you touch the vehicle and the ground at the same time, that protection ends entirely.

If a downed power line lands on or touches your vehicle, stay inside unless smoke or fire makes the cabin itself immediately dangerous. Call 911 and loudly warn anyone nearby, including someone trying to help you, to stay back at least 30 to 35 feet, since the ground around the vehicle can be energized even without visible sparking, and a downed line frequently shows no obvious sign of being live. Sound your horn and wait for trained utility or emergency personnel to confirm the line has been de-energized before anyone exits the vehicle under normal circumstances.

• If smoke or fire genuinely forces you to exit, the technique matters as much as the decision to leave. Open the door fully without touching anything on the outside of the vehicle. Cross your arms over your chest so your hands stay away from the metal door frame. Jump completely clear of the vehicle with both feet together, landing with your feet still together; you must never touch the vehicle and the ground at the same moment, since that creates a path for current to flow directly through your body.
• Once on the ground, shuffle or hop away, keeping both feet together and on the ground at all times, rather than walking normally. The ground around a downed line carries varying voltage at different points, like ripples spreading outward from where the wire touches down, and lifting one foot while the other remains planted can let current enter through one foot and exit through the other, using your body as the path between two different voltage points. Continue shuffling or hopping until you are at least 30 to 35 feet from the vehicle.
• Never hold hands with another person while doing this, even a child, since joined hands can extend the electrical path between two people rather than protecting either one.

05 — Carjacking and vehicle theft awareness during extended disruptions

Opportunistic crime, including vehicle-related crime, can rise during disasters and extended outages, when normal routines, lighting, and law enforcement presence are all disrupted at once. The core defensive habits are simple and apply whether or not a disaster is underway.

Keep your doors locked and windows up while driving and at stops, and stay genuinely alert to your surroundings, particularly at intersections, gas stations, and any place you are stopped with the vehicle stationary for more than a moment.

• Do not stop for strangers flagging you down on dark or isolated roads. If someone appears to need help in this situation, call 911 and report the location rather than stopping yourself; this protects both you and, genuinely, gets the person faster, more appropriate help than an unprepared bystander could provide.
• Park in visible, well-lit areas whenever the choice is available, since visibility itself is a real deterrent against opportunistic crime, which tends to favor cover and low visibility.
• If you are confronted and someone demands the vehicle, give it up without resistance. No vehicle, regardless of what it contains or what it represents to your immediate plans, is worth risking your life or a passenger's life over. This is consistently the guidance from law enforcement and safety organizations across vehicle theft and carjacking situations generally, not a recommendation specific to disaster conditions.