Dense Superfog, Tule Fog, kple Ʋu Geɖewo ƒe Mɔdodo Gãwo ƒe Ƒuƒoƒo ƒe Agbetsitsi¶

Superfog, radiation fog ("pea-soup fog"), kple tule fog nye anyigba ƒe nukpɔkpɔ ƒe elektrikŋusẽ ƒe nutsotso kpata si hea ʋu geɖe ƒe mɔdodo gã dzi ƒe ƒuƒoƒo gãtɔ kple esi wua ame wu le ʋuɖoɖo ŋutinya me vɛ, zi geɖe la, elɔa ʋu 50 va ɖo 200+ ɖe eme le kɔsɔkɔsɔ ƒe afɔku si xɔa miniti geɖe me. Togbɔ be afu dzɔdzɔe si me ʋuʋudedi le ɖea ʋukulawo ƒe nukpɔkpɔ dzi kpɔtɔna va ɖoa meta 400 (kilometa 0.25) hã la, tule fog (kuɖiɖi si me keklẽŋusẽ le si gbɔ eme si yɔa California ƒe Titina Bali kple tɔsisi goglowo me le xexeame katã le dzomeŋɔli) ɖea nukpɔkpɔ dzi kpɔtɔna wu meta 30 va ɖo 60 (afɔ 100 va ɖo 200), kple superfog (si dzɔna ne tsi xɔ dzo dzudzɔ si le dzudzɔ tum le agado, peat, alo dzobibi me tsaka kple ya fafɛ si yɔ fũ) ɖea nukpɔkpɔ dzi kpɔtɔna va ɖoa mede meta 1 va ɖo 3 (afɔ 3 va ɖo 10), si naa ʋukulawo ƒe ŋku gbã keŋkeŋ hafi woate ŋu akpɔ woawo ŋutɔ ƒe ʋu ƒe ʋuƒo ƒe atsyɔ̃ɖonu gɔ̃ hã.

United States Dukɔa ƒe Mɔdodowo Dzikpɔƒe (FHWA), Dukɔa ƒe Yame ƒe Nɔnɔme Ŋuti Dɔwɔƒe (NWS), Dukɔa ƒe Ʋuɖonyawo Gbɔkpɔha (NTSB), kple Eŋlisiawo ƒe Ʋuɖonyawo Gbɔkpɔha gblɔ be mɔdodo gãwo dzi ƒuƒu siwo do ƒome kple afu wua ʋukula alafa geɖe ƒe sia ƒe le mɔ̃ eve siwo wotsɔ ƒoa ƒui ta. Gbã la, le afu si me vovototo boo aɖeke mele o si me mɔ to nufiaƒe siwo le teƒe ɖeka mele o me la, amegbetɔ ƒe ahɔhɔ̃ kpea fu le nukpɔkpɔ ƒe susu (vovototodedeameme ƒe duƒuƒu nu tsɛe) si nana ʋukulawo sena le wo ɖokui me abe ɖe wole tsatsam ene ne wole ʋu kum ŋutɔŋutɔ le kilometa 90 va ɖo 110 le gaƒoƒo ɖeka me (kilometa 55 va ɖo 70 le gaƒoƒo ɖeka me), si sesẽ wu alesi woƒe akaɖiwo ate ŋu aɖe ʋu si tɔ ɖe ŋgɔ la afia (ku ʋukuku wògbɔ eme wò ŋku ƒe didime). Evelia.

Wɔ esia fifia¶

1. Switch Headlights to LOW BEAMS immediately and NEVER use High Beams (Brights) in fog. High-beam headlights angle light upward into the suspended water droplets and smoke particles of the fog bank, reflecting a blinding white glare (backscatter) straight back into your own eyes like shining a flashlight into a mirror. Switch manually from "Auto" to Low Beams, turn on front and rear fog lights if equipped, and dim your interior dashboard screen so your pupils can see faint taillights ahead.
2. Slow down smoothly BEFORE entering a visible fog bank so your stopping distance is shorter than your sight distance. At 105 kilometers per hour (65 miles per hour) on wet pavement, an average passenger car requires at least 95 to 110 meters (310 to 360 feet) to perceive a hazard, react, and brake to a stop, while a loaded 36-metric-ton (80,000-pound) semi-truck requires 135 to 160+ meters (450 to 525+ feet). If you can only see 30 meters (100 feet) ahead in dense tule fog, driving any faster than 40 kilometers per hour (25 miles per hour) means you will hit a stopped car before your brakes can stop you.
3. Track the painted white right-edge fog line with your eyes, NEVER "lock onto" the taillights of the car ahead, and roll down your window to LISTEN. Watching the taillights of the car in front of you in dense fog causes target fixation (moth-to-a-flame effect): if that driver drifts off a bridge, swerves into a ditch, or slams into a stopped semi-truck, you will follow them straight into the crash. Guide your lane position using the solid white right-edge pavement line, turn off your radio, roll your driver's window down 5 centimeters (2 inches), and listen for the sound of screeching tires, crunching metal, or horns ahead.
4. If visibility drops to near zero (<3 to 10 meters / 10 to 33 feet), exit the highway at the next ramp or pull completely off the pavement, TURN OFF ALL LIGHTS, and take your foot off the brake pedal. If you are forced to pull onto a wide roadside shoulder or grass median because you cannot see to drive, pull as far right as physically possible (past the guardrail if safe), put the vehicle in Park, set the parking brake, and turn your headlights and brake lights OFF (or use hazard flashers only while still moving toward the exit). In dense fog, blinded drivers behind you will steer toward your glowing red brake lights thinking you are driving in the active lane, causing them to rear-end you on the shoulder.
5. If you crash or get caught inside a multi-vehicle highway pileup: KEEP YOUR SEATBELT BUCKLED and stay inside your car unless it is on fire or you can drive/sprint past the guardrail. Inside an active fog pileup, cars and semi-trucks continue crashing into the rear of the pileup every 3 to 10 seconds for several minutes. Never step out of your car onto the highway pavement or walk between wrecked cars.
6. If your car can still move after a minor tap: Drive it immediately forward and far off the right side of the highway past the wreckage zone and past the guardrail.
7. If your car is immobilized in the highway lanes: Keep your seatbelt fastened, keep your head pressed firmly against the headrest (to prevent cervical whiplash from secondary rear impacts), keep your hands off the steering wheel airbag cover, and wait until the sounds of crashing behind you have completely stopped before exiting toward the far side of the concrete barrier or ditch.
8. Call emergency services with your exact highway milepost marker and direction of travel. Once protected inside your braced vehicle or safely behind a concrete Jersey barrier/guardrail 30 meters (100 feet) away from the pavement, call your local emergency number (911 in the United States and Canada, 112 across the European Union, 999 in the United Kingdom, or see all xexlẽdzesi siwo wozãna kpata) and report the highway number, direction (northbound/southbound), and nearest milepost marker.

Dense fog driving and multi-vehicle highway pileup survival flowchart¶

Use this real-time survival flowchart when encountering a sudden wall of superfog or tule fog on a high-speed freeway.

flowchart TD
    Start["Driving on Highway Approaches Dense Fog:<br/>Radiation Fog, Tule Fog, or Smoke-Fog ('Superfog')"] --> PrepStep["IMMEDIATE PRE-ENTRY ACTIONS:<br/>1. Switch headlights manually to LOW BEAMS (NEVER High Beams)<br/>2. Turn ON front & High-Intensity Rear Fog Lights<br/>3. Disengage Cruise Control & Adaptive Autopilot immediately<br/>4. Turn OFF radio, crack window 5 cm (2 in) to LISTEN for crashes"]

    PrepStep --> VisCheck{"How far ahead can you see<br/>stationary road objects?"}

    VisCheck -->|"Moderate-to-Dense Fog<br/>(60 to 150 m / 200 to 500 ft visibility)"| DriveSlow["CONTROLLED FOG DRIVING:<br/>1. Reduce speed smoothly to 50 to 70 km/h (30 to 45 mph)<br/>2. Increase following gap to 8 to 12 seconds (never tail taillights)<br/>3. Track the white right-edge pavement fog line<br/>4. Watch for Black Ice if temperature is <= 0 C (32 F)"]

    VisCheck -->|"EXTREME TULE FOG / ZERO-VISIBILITY SUPERFOG<br/>(< 3 to 30 m / 10 to 100 ft visibility)"| ZeroVis["EMERGENCY HIGHWAY EXIT PROTOCOL:<br/>1. Do NOT slam on brakes in the middle of a traffic lane<br/>2. Take the VERY NEXT EXIT RAMP to a parking lot<br/>3. If no exit: Pull completely OFF pavement past shoulder/guardrail,<br/>   set Parking Brake, take foot OFF brake pedal, & TURN LIGHTS OFF<br/>   (so blinded drivers behind do not steer into your taillights)"]

    DriveSlow --> CrashCheck{"Did you hear crunching metal ahead<br/>OR get caught in a Pileup Crash?"}
    ZeroVis --> CrashCheck

    CrashCheck -->|"YES: Caught in Active Multi-Car Pileup"| PileupTriage{"Can your vehicle still steer<br/>and roll forward?"}

    PileupTriage -->|"YES: Vehicle still drivable"| DrivePast["DRIVE OUT OF THE KILL ZONE:<br/>Steer immediately forward/right past the crashed cars<br/>and pull far off the highway onto the grass/beyond guardrail"]

    PileupTriage -->|"NO: Vehicle immobilized in lanes"| StayOrFlee{"Is your car on fire OR at the<br/>very back edge with clear guardrail escape?"}

    StayOrFlee -->|"No fire & cars still crashing all around"| BraceInside["NƆ KPƆ KPƆKPƆ LE GAKPƆKPƆA ME:<br/>1. Na zikpuimeka nanɔ sesĩe & te ta ƒe megbe ɖe Taɖodzinu<br/>2. MÈGA tsi tre ɖe ʋu siwo gbã dome le mɔdodo dzi GBEÐE o<br/>3. Lala vaseɖe esime toɣliɖeɖe siwo katã le ʋuʋum la natɔ hena sɛkɛnd 60+"]

    StayOrFlee -->|"Ʋu si le dzo dam ALOO dedie dometsotso be nàdo le ɖusime"| SprintBarrier["ƉE ƲUƲU TO DZƆDZƆƑE ƑE ƲUƲU ƑE ƲUƲU:<br/>Ðe ka, do go le adzɔge tso ʋu siwo gbɔna gbɔ, lia TO<br/> dzɔlawo ƒe mɔxenu/Jersey ƒe mɔxenu la dzi, eye nàʋu 30+ m (100+ ft) TSITSI/GODO"]

Mɔdodo gãwo dzi afu ƒomevi 5 siwo wua ame wu kple woƒe dzɔdzɔmeŋusẽŋununya tsɔtsɔ sɔ kple wo nɔewo¶

Menye afuwo katãe wɔa nu ɖekae o. Togbɔ be zi geɖe la, ƒuta ƒumelãwo ƒe advection fog dzina ɖe edzi vivivi le gaƒoƒo geɖe me hã la, keklẽ ƒe afu, tule fog, freezing fog, kple superfog ƒoa ƒu alo ta aɖe le mɔdodo gã siwo me tsi nyrɔna le bɔbɔe kple tɔsisiwo ƒe tɔdzisasrãwo me le aɖabaƒoƒo ʋɛ aɖewo ko me, si léa ʋukulawo siwo le ʋuʋum le \(110\text{ km/h}\) (\(70\text{ mph}\)) dzi le vome kura.

Deep dive 1: The physics of "Superfog" (Why smoke + cold damp air creates a 1-meter whiteout)¶

Meteorologists at the US Forest Service and NOAA discovered through laboratory wind-tunnel and field studies why superfog is ten times denser than normal meteorological fog: 1. Dzɔdzɔme Fog vs. Smoke-Nucleated Superfog: Le kɔƒenutome ya dzadzɛ me la, ke suesuesue siwo wokpɔna (Cloud Condensation Nuclei [CCN]) ƒe xexlẽme seɖoƒe li na tsi ƒe dzoxɔxɔ be wòaƒo ƒu ɖe edzi. Esia wɔe be dzɔdzɔme keklẽŋusẽ ƒe afu wɔa tsi si lolo vie ƒe xexlẽme si sɔ (\(15\text{ va ɖo }30\text{ micrometers}\) le woƒe didime nu), si gblẽa dometsotsowo ɖi be kekeli nato eme ale be nàte ŋu akpɔ \(50\text{ va ɖo }200\text{ mita}\) le ŋgɔ kokoko. 2. The Smoldering Wildfire / Marsh-Fire Multiplier: Ne dzo si te ɖe agado me, peat bog dzo, brɔs dzo, alo avewo ƒe dzobibi trɔ tso dzobibi si le dzo dam le ŋdɔ me va zu dzobibi si le dzo dam le zã me la, eɖea nu eve ɖe go le anyigba tututu: - Dzudzɔ ƒe akpa biliɔn geɖe siwo wotsɔa nusuekpɔmɔ̃ ƒoa tsii (siwo hea tsi) le kubik sentimeta ɖeka me, AND - Tsi ƒe dzoxɔxɔ gbogbo aɖewo si woɖa tso anyigba xɔdzo, peat, kple numiemie damawo me. 3. Ya Fafɛ ƒe Tsi kple Dzoxɔxɔ ƒe Trɔtrɔ: Le zãtitina kple ŋdi ga 8:00 dome la, zã me ya fafɛ sina yia anyigba ƒe nɔnɔme siwo bɔbɔ wu me, siwo nye ɣesiaɣi kloe tɔsisiwo gɔme, agadowo ƒe tsidzɔƒewo, kple mɔdodo gãwo ƒe mɔ ƒe gomenɔamesi. Ne dzudzɔ si le dzo dam si me tsi sɔ gbɔ ɖo la tsaka kple ya fafɛ si me tsi yɔ fũ (\(100\%\) fafa si sɔ gbɔ, dzoxɔxɔ ƒe vovototo \(\ge 10^\circ\text{C}\) [\(18^\circ\text{F}\)]), tsidzadzaa ƒoa ƒu ɖe dzudzɔ suesuesue ɖekaɖeka ɖesiaɖe dzi le ɣeyiɣi ɖeka me, si wɔnɛ be dzudzɔ sue miliɔn geɖe ƒe ʋuʋudedi si lolo akpa la dona \(2\text{ vaseɖe }5\text{ micrometer}\) tsitetewo le kubik mita ɖeka me si kaka kekeli si wokpɔna ƒe alafa memama 99.9 le \(1\text{ vaseɖe }3\text{ mita}\) (\(3\text{ vaseɖe }10\text{ feet}\)) me. 4. **Superfog Afɔku Xɔŋkɔ Siwo Dzi Nàɖo Ŋku **: - Interstate 55 si te ɖe New Orleans / Lake Maurepas, Louisiana (October 23, 2023): Dzo si le dzudzɔ tum le ƒuta marsh peat dzowo tsaka kple ŋdi me afu tsɔ wɔ superfog to I-55 tɔdzisasrã eve siwo kɔ dzi, si na ʋu 168 ƒe ƒuƒoƒo kple tanker dzo si wu ame 8 eye ame 63 xɔ abi. - Interstate 75 le Paynes Prairie si te ɖe Gainesville, Florida ŋu (January 29, 2012): Dzudzɔ si tso dzo si bi le brɔs me le gbedadaƒo ƒe tsidzɔƒe la tsaka kple zã me keklẽŋusẽ ƒe afu, si na nukpɔkpɔ dzi ɖe kpɔtɔ va ɖo meta 1 eye wòna ʋu 25+ kple agbatsɔʋu afãwo ƒe ƒuƒoƒo si wu ame 11. - Interstate 4 le Polk County, Florida (January 9, 2008, ʋu 70) kple Interstate 75 si te ɖe Calhoun, Tennessee ŋu (December 11, 1990, ʋu 99).

Sight distance vs. braking distance table: Aleke gbegbee nàte ŋu aku ʋu sesĩe ŋutɔŋutɔ le afu me?¶

Ʋukula akpa gãtɔ siwo le afu me wua ame kua woƒe akaɖiwo kple nukpɔkpɔ ƒe didime si gbɔ eme. Zã dzɔdzɔmeŋusẽŋununya ƒe kplɔ̃ sia (si wobu tso AASHTO mɔdodo gã dzi tɔtrɔ nukpɔkpɔ ƒe didime ƒe nɔnɔmetatawo me to \(2.0\text{-second}\) sidzedze-nuwɔna ƒe ɣeyiɣi si wodzrana ɖo le afu ƒe afɔtoƒe si xɔ dzo dzi) nàtsɔ akpɔ duƒuƒu si le dedie wu bliboe na nukpɔkpɔ ƒe didime ɖesiaɖe si wona:

Deep dive 2: The "Taillight Moth Effect" and why you must turn your lights OFF when parked on the shoulder¶

Se siwo tsi tre ɖe nukpɔsusu ŋu wu siwo California Mɔdododzikpɔha (CHP) wɔna le Central Valley tule ƒe afu ƒe ɣeyiɣiwo me kple esiwo dziɖuɖua ƒe mɔdododzikpɔlawo wɔna le dukɔa me godoo dometɔ ɖekae nye Parked Shoulder Lights-Off Protocol: - Alesi "Nudzodzoe ƒe Ŋusẽkpɔɖeamedzi" wɔa dɔe: Ne vɔvɔ̃ ɖo ʋukula aɖe eye wògbã ŋku le afu gã aɖe me la, woƒe ŋkuwo tsɔa mɔkpɔkpɔbuɖeame léa ŋku ɖe ƒuƒlu ɣia ŋu be yewoakpɔ seke ɖesiaɖe si woakpɔ. Zi alesi wokpɔ megbekaɖi dzĩ siwo le keklẽm alo afɔku ƒe akaɖi siwo ƒe amadede nye aŋutiɖiɖi siwo le keklẽm le wo ŋgɔ ko la, wokplɔa ʋua le akaɖi mawo megbe tẽ le manyamanya me, eye wotsɔe be ʋu ma le zɔzɔm le mɔ si dzi ʋuwo le zɔzɔm le la dzi. - Nusi Dzɔna Ne Ètɔ Ðe Abɔta Kple Wò Afɔ Le Brek Dzi: Ne èhe mɔ gã si wotsɔ kpe gbadzɛwo ɖo ƒe abɔta le afu gã aɖe me eye nènɔ anyi ɖe afima kple wò ŋgɔgbekaɖiwo le keklẽm, wò afɔku ƒe akaɖiwo le keklẽm, eye wò afɔ le brek ƒe afɔti tem (si le wò brek ƒe akaɖi dzĩ siwo le keklẽm la klẽm), ** ʋukulawo siwo te ɖe ŋuwò tso megbe mate ŋu akpɔ wò abɔta ƒe fli ɣi si wota la o la, ɖeko wokpɔa wò akaɖi dzĩwo eye nèkua ʋua ɖe ɖusime ɖe abɔta yi wò ʋu si nètɔ la ƒe megbe**. - Ʋutɔɖoƒe Kpata ƒe Ðoɖo Nyuitɔ le Zero-Visibility Fog me: 1. Le mɔ nyuitɔ nu la, mègatɔ ɖe mɔ gã ƒe abɔta gbadza si wotsɔ kpe gbadzɛwo tu dzi gbeɖe o; ʋuʋu blewuu le mɔ si kplɔe ɖo si dzi woato ado le eme la dzi ayi mɔ̃memidzraƒe alo asitsaƒe ƒe ʋutɔɖoƒe si kekeli le nyuie. 2. Ne wò mɔ̃a tɔ alo nukpɔkpɔ zero zi dziwò be nàdo le mɔa dzi le afisi mɔ si dzi nàto ado le meli o la, ke ʋu adzo le mɔ si wotsɔ kpe gbadzɛwo tu la dzi alesi nàte ŋui, yi gbea dzi le mɔ si dzi nàto alo le dzɔla aɖe megbe keŋkeŋ. 3. Trɔ yi Tɔdziʋu me, tsɔ kpata/ʋutɔɖoƒe ƒe brek, ɖe wò afɔ ɖa keŋkeŋ le afɔ brek ƒe afɔti dzi, eye TSI gota akaɖiwo katã (kaɖiwo, megbekaɖiwo, kple afɔku ƒe akaɖiwo) ale be ʋuwo yometiti nakplɔ mɔ gã ƒe afɔtoƒe tsɔ wu be nàku ʋua ayi wò ʋu si nètɔ la me. 4. If it is safe to exit on the away-from-traffic side, evacuate everyone out of the parked car and stand 15 to 30 meters (50 to 100 feet) away behind a guardrail, tree line, or high embankment.

Step-by-step survival inside a 100-car highway pileup¶

If you hear the unmistakable sound of crunching metal and screeching tires inside the fog ahead of you, or if your vehicle crashes into the back of an active multi-vehicle pileup, every second counts. In major fog pileups (such as the 1990 Calhoun I-75 crash, the 2002 I-710 Long Beach crash, the 2013 Sheppey Crossing crash in the UK, or the 2023 Louisiana I-55 crash), secondary impacts continue slamming into the rear of the pileup for 2 to 8 minutes after the first crash.

Akpa 1: Ne Wò Ʋu Tɔtɔ Makpɔmakpɔ ALOO Ate Ŋu Agate Ŋu Aʋuʋu Le Edzidzedze Vɔ Megbe¶

1. Do NOT stay stopped at the back of the pileup in the travel lanes. The "tail end" of the pileup is the active impact zone where the next 36-ton semi-truck is about to hit in 3 seconds.
2. Ne wò ʋu ate ŋu akplɔ ʋu ahaku ʋu kokoko: Tsɔ ʋua ƒo xlã ʋu siwo ge le ŋgɔwò enumake alo ʋu sesĩe tso mɔ gã la ƒe mɔdodo dzi tututu yi gbe ƒe abɔta/tɔdzisasrãa dzi do ŋgɔ na ʋu gbagbãawo eye nàdzo le wo gbɔ, nàto dzɔlawo ƒe ʋuƒoa ŋu alesi nàte ŋui.

Phase 2: If Your Vehicle Is Crushed, Wedge-Trapped, or Immobilized in the Lanes¶

1. NEVER unbuckle and step out onto the highway pavement between wrecked cars. Standing on the asphalt between two crashed cars in zero-visibility fog is fatal: when a semi-truck hits the back of the pileup 50 meters behind you, the entire accordion of wrecked cars shoves forward by 5 to 15 meters in an instant, crushing anyone standing between bumpers or throwing them under wheels.
2. Use Your Car's Steel Safety Cage as Armor While Impacts Continue:
3. Keep your seatbelt buckled tight. Modern vehicle crumple zones, side-curtain airbags, and high-strength boron-steel cabin pillars can absorb multiple 60 km/h impacts that would instantly kill an unbuckled occupant or pedestrian.
4. Brace for Rear-End Impact: Press the back of your head and shoulders flat against the seat headrest (closing the gap between your skull and the headrest reduces cervical spine whiplash forces by up to 70 percent), look straight ahead, and keep your hands and arms away from the center of the steering wheel (in case a secondary impact deploys an unpopped airbag).
5. The Two Exceptions Where You MUST Evacuate the Vehicle Immediately:
6. Exception A (Fire or Hazardous Fuel Spill): If you see flames, smell spilled gasoline/diesel, hear a ruptured tanker hissing, or see an Electric Vehicle (EV) battery smoking underneath the pileup, unbuckle immediately, climb out the window or door facing away from oncoming traffic, and scramble over the nearest concrete barrier or guardrail.
7. Exception B (You Are the Last Car at the Very Rear of the Pileup Right Next to a Guardrail): If your car is immobilized at the exposed rear edge of the crash right next to the outside shoulder and you have a clear 2-second jump over the guardrail before the next car arrives, jump over the guardrail immediately and run 30+ meters (100+ feet) outward and UPSTREAM (back toward the direction traffic is coming from, behind the guardrail, so flying car debris does not hit you, note that on an elevated bridge deck with no land beside it, climb onto or behind the concrete bridge Jersey barrier and run forward past the front of the pileup).

Pre-trip checklist for driving in Tule Fog and Superfog corridors¶

Before driving between November and March in valley fog basins (such as California's I-5 and Highway 99) or early morning along coastal marsh highways:

• Check state DOT highway cameras and "Superfog / Dense Fog Advisories" before departing: If visibility is reported below 60 meters (200 feet) or if wildfire smoke warnings overlap with a Dense Fog Advisory, delay your trip until 10:00 AM to 11:00 AM after solar heating mixes out the ground inversion.
• Clean the INSIDE and OUTSIDE of your windshield and replace worn wiper blades: Microscopic fog droplets condense on windshield grime, and interior dashboard off-gassing film scatters oncoming headlight glare across your glass. Run your front windshield defroster (with A/C compressor ON to dehumidify the cabin air) and rear window defogger continuously.
• Know where your manual headlight switch and Rear Fog Light button are BEFORE entering fog: Many European and modern vehicles feature a dedicated High-Intensity Rear Fog Light (a single bright red light on the driver's side rear bumper equal in brightness to a brake light, marked by a lamp icon with wavy lines facing right) specifically engineered to pierce tule fog and Autobahn fog without confusing brake lights.
• Keep a window-breaker / seatbelt-cutter tool mounted within reach of the driver's seat: If a multi-car pileup pins your doors shut and a post-crash fire starts, a spring-loaded tungsten-carbide punch shatters tempered side-window glass in one second; see our car crash guide.

Nya siwo wobiaa amewo enuenu¶

Why should you never use high-beam headlights (brights) in dense fog?¶

High-beam headlights are angled upward and straight ahead to illuminate distant road signs on clear nights. In dense fog, billions of microscopic suspended water droplets sit directly in front of your bumper; when upward-angled high beams hit those droplets, the light reflects and scatters straight back into your own eyes (a physics phenomenon called Mie backscatter), creating a blinding white wall of glare that actually reduces how far you can see. Low-beam headlights and dedicated front fog lights are angled downward toward the pavement underneath the densest layer of fog, illuminating the lane stripes while minimizing glare.

What is "Superfog," and how is it different from normal dense radiation fog or tule fog?¶

Normal dense fog (including California's tule fog) forms when clear, calm night skies chill damp ground air below its dew point, typically reducing visibility to between 10 and 400 meters (33 to 1,300 feet). Superfog is a far denser, localized hybrid phenomenon that occurs when damp, smoldering smoke from a wildfire, marsh fire, peat fire, or prescribed burn mixes with cool, saturated night or early-morning air. The smoldering fire injects both extra water vapor and billions of microscopic smoke particles (cloud condensation nuclei) into the cold air, creating an ultra-dense whiteout cloud that drops visibility from completely clear to less than 1 to 3 meters (3 to 10 feet) in seconds.

Why do Highway Patrol officers tell you to turn your headlights and taillights OFF if you are forced to park on the highway shoulder in dense fog?¶

In near-zero visibility fog, drivers still moving on the highway suffer from a well-documented visual tracking reflex called the "moth effect" (target fixation): because they cannot see the pavement edges clearly, they lock their eyes onto the red taillights of the vehicle ahead of them and steer directly behind those lights. If you pull off onto the shoulder and sit parked with your taillights, hazard lights, or brake lights glowing, blinded drivers approaching from behind will assume you are driving in the active lane, steer off the road to follow your lights, and slam directly into the back of your parked car. Always exit the highway completely if possible; if forced onto the shoulder, pull far off the pavement past the guardrail, set the parking brake, take your foot off the brake pedal, and turn off all exterior lights.

If my car is involved in a multi-vehicle fog pileup, is it safer to stay inside my car or get out and run?¶

Unless your car is on fire, leaking fuel, or can still be driven forward out of the crash zone, it is almost always safer to stay inside your vehicle with your seatbelt tightly buckled and your head braced against the headrest until the crashing behind you stops. Inside an active zero-visibility fog pileup, additional cars and semi-trucks continue slamming into the rear of the wreckage every few seconds at highway speed; stepping out onto the pavement between wrecked cars exposes your unarmored body to being crushed between shifting bumpers or struck by swerving vehicles. Only exit on foot if fire threatens the cabin or if you have a clear, immediate step directly over a concrete barrier or guardrail away from all traffic lanes.

Wolé ŋku ɖe dzɔtsoƒewo ŋu¶

• Federal Highway Administration (FHWA, United States Department of Transportation): Low-Visibility and Dense Fog Driving Safety Countermeasures, Stopping Sight Distance Physics (AASHTO Green Book), and Variable Speed Limit (VSL) Corridor Studies.
• National Weather Service (NWS / NOAA, United States): Dense Fog Advisory Criteria, California Central Valley Tule Fog Climatology, and Superfog Forecasting Parameters (US Forest Service / NWS Spot Forecast Superfog Matrix).
• National Transportation Safety Board (NTSB, United States): Highway Accident Reports on Multi-Vehicle Fog and Superfog Pileups (Calhoun, TN I-75; Gainesville, FL I-75; and St. John the Baptist Parish, LA I-55).
• California Highway Patrol (CHP) and Caltrans (United States): Central Valley Tule Fog Driver Survival Guidelines, Pace-Car Operations, and Shoulder Parking Lights-Off Protocol.
• Department for Transport (DfT, United Kingdom) and UK Highway Code: Rules 226 to 237 (Driving in Fog and Freezing Fog, Use of High-Intensity Rear Fog Lamps, and Motorway Pileup Evacuation Behind Crash Barriers).

Mɔfiame siwo do ƒome kplii¶

• Car crash: immediate steps, first aid, and highway safety
• Flash freeze and black ice driving survival
• Dzo ƒe dzudzɔ kple aŋɔ si wogbɔna
• Dust storms and haboob highway survival
• Car breakdown: highway shoulder survival