Dense Superfog, Tule Fog, n'Imiduga myinshi y'Ibarabara Rikomeye ry'Ukurokoka¶

Superfog, radiation fog ("pea-soup fog"), na tule fog ni ugucika kw'ibara ry'umuco ku rugero rwo hasi bitera amabarabara menshi kandi yica abantu benshi mu mateka y'ivy'ugutwara abantu n'ibintu, akenshi bikaba bituma **50 gushika ku 200+ y'ibinyabiziga bipfa. iminota. Mu gihe igihu gisanzwe gikomeye kigabanya ukuntu umushoferi abona neza gushika nko ku metero 400 (0.25 miles), igihu c’imishwarara (igihu c’imishwarara ikaze cane cuzuye mu kiyaya co hagati ca California no mu binogo vy’inzuzi zikomeye kw’isi yose mu rushana) kigabanya ukuntu abona munsi ya 30 gushika ku metero **00 ku **0fo) (ibaho iyo umtsi w’ibitovu, w’ivu canke w’umuriro w’ishamba uvanze n’ikirere gikonje cuzuye) bituma umuntu abona neza gushika ku metero 1 gushika kuri 3 (amafuti 3 gushika ku 10), bikaba bihuma amaso abashoferi imbere y’uko mbere babona ivyiza vyo ku mutwe w’imodoka yabo bwite.

Dukurikije ibivugwa n’ubuyobozi bwa Leta Zunze Ubumwe za Amerika bujejwe amabarabara manini (FHWA), ikigo c’igihugu kijejwe ivy’imihindagurikire y’ikirere (NWS), ikigo c’igihugu kijejwe umutekano mu bijanye n’ivy’ugutwara abantu n’ibintu (NTSB), be n’Igisata c’Ubwongereza kijejwe ivy’ugutwara abantu n’ibintu, ibirundo vy’amabarabara biva ku gihu bica amajana y’abatwara imodoka buri mwaka kubera imitego ibiri itera imbere. Ica mbere, mu gihu gifise ubudasa buke ata n’ibimenyetso bihagaze ku ruhande rw’inzira, ubwonko bw’umuntu burashikirwa n’ukwihenda kw’amaso (ugufata umuvuduko muto bitewe n’ubudasa) bituma abashoferi bumva ko bariko barakwegakwega igihe mu vy’ukuri bariko batwara imodoka ku **bilometero 90 gushika ku 110 kw’isaha (55 kugeza kuri 7 hour) guhishura imodoka ihagaze imbere (gutwara kure y’aho ubona). Ubwa kabiri, iyo iyo mpanuka y’intango ibaye imbere mu nzu y’igihu idashobora kuboneka, abashoferi bafungura umukanda wabo bagasohoka ku nzira y’amabarabara kugira ngo basuzume ivyononekaye, barakubitwa maze bakicwa haciye amasegonda makeyi n’ibikamyo bimwe bimwe be n’imiduga irima ata co ibona mu bimeneke bivuye inyuma.

Ivyo ubikore ubu¶

1. Hindura amatara y’imbere ku MURI WA MUSI ubwo nyene kandi NTUZOKWIGEZE ukoresha amatara maremare (Imuco) mu gihu. Amatara y’imbere y’umuco muremure ahindura umuco hejuru mu matosi y’amazi n’ibice vy’umwotsi vy’uruzitiro rw’igihu, yerekana umuco w’umweru uhuma amaso (backscatter like your backscatter into your backscatter) indorerwamo. Hindura n'amaboko kuva kuri "Auto" ushire kuri Low Beams, ushireko amatara y'imbere n'ay'inyuma nimba afise, hanyuma ushireko umuco ku gicapo ca dashboard yawe yo mu mutima kugira ngo abanyeshure bawe babone amatara y'inyuma atari menshi imbere.
2. Gaba buhoro neza IMBERE yo kwinjira mu nkombe y’igihu iboneka kugira ngo urugendo rwawe rwo guhagarara rube rugufi kuruta urugendo rwawe rwo kubona. Ku bilometero 105 kw’isaha (65 miles kw’isaha) ku nzira y’amabuye itose, imodoka y’abantu isanzwe isaba **nibura metero 95 gushika kuri 110 (310 to fee,0ived) kandi ugahagarika kugira ngo uhagarare, mu gihe ikamyo y’igice y’amatoni 36 (amapawundi 80.000) yuzuye isaba metero 135 gushika kuri 160+ (amafuti 450 gushika kuri 525+). Niba ushobora kubona gusa metero 30 (amafuti 100) imbere mu gihu gikomeye c’i tule, gutwara imodoka yihuta kuruta ibilometero 40 kw’isaha (25 miles kw’isaha) bisigura ko uzotera imodoka ihagaze imbere y’uko amaferemi yawe aguhagarika.
3. Kurikirana n'amaso yawe umurongo w'igihu w'iburyo w'umweru ushizweko ibara, NTUZIGEZE "ufunga" amatara y'inyuma y'imodoka iri imbere, hanyuma ushire hasi idirisha ryawe kugira ngo WUMVIRE. Kwitegereza amatara y'inyuma y'imodoka iri imbere yawe mu gihu gikomeye bituma **gushikama kw'intumbero (moth-to-a-me-f:ves) mu mwobo, canke ugatera mu gice c’ikamyo gihagaze, uzobakurikira ugororotse mu mpanuka. Yobora aho uri mu murongo ukoresheje umurongo ukomeye w’umweru uri ku ruhande rw’iburyo, uzime iradiyo yawe, ushire idirisha ry’umushoferi wawe hasi ku masentimetero 5 (inci 2), kandi wumvirize ijwi ry’amapine atera, ivyuma bitera, canke amahembe ari imbere.
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 inomero z'ivyihutirwa) 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["STAY BUCKLED INSIDE THE STEEL CAGE:<br/>1. Keep seatbelt tight & press back of head against Headrest<br/>2. NEVER stand between wrecked cars on the pavement<br/>3. Wait until all crashing noises stop for 60+ seconds"]

    StayOrFlee -->|"Car on fire OR safe gap to exit right"| SprintBarrier["EVACUATE PAST THE GUARDRAIL:<br/>Unbuckle, exit away from oncoming traffic, climb OVER<br/>the guardrail/Jersey barrier, and move 30+ m (100+ ft) UPSTREAM/OUTWARD"]

Comparing the 5 deadliest highway fog types and their physics¶

Not all fog behaves the same way. While coastal marine advection fog usually builds gradually over hours, radiation fog, tule fog, freezing fog, and superfog form or pool inside low highway dips and river bridges within minutes, catching drivers moving at \(110\text{ km/h}\) (\(70\text{ mph}\)) completely off guard.

Deep dive 1: Fizike ya "Superfog" (Kubera iki umwotsi + umuyaga ukonnye utose bituma habaho ukwera kw'imetero 1)¶

Abahinga mu vy’imihindagurikire y’ikirere bo mu kigo ca Amerika citwa Forest Service na NOAA bavumbuye biciye mu nyigisho zakozwe mu laboratwari n’ivy’imiyaga igituma superfog ari nyinshi incuro cumi kuruta igihu gisanzwe c’imihindagurikire y’ikirere: 1. Igihu c’ibidukikije n’igihu c’umwotsi gikomeye: Mu kirere gisukuye co mu ntara, hariho umubare mutoyi w’ibice vy’inkungugu bitobito (Igihu c’Igicu [CCN]) kugira ngo umwotsi w’amazi ushireko. Ivyo bituma igihu c’imishwarara kamere gihingura umubare uringaniye w’amatonyanga y’amazi manini cane (\(15\text{ gushika }30\text{ micrometers}\) mu gipimo), ivyo bikaba bisiga ibihengeri kugira ngo umuco unyuremwo kugira ngo ushobore kubona \(50\text{ gushika }200\text{ metres}\) imbere. 2. Umuriro w’Ishamba / Umuriro w’Ishamba: Iyo umuriro w’ishamba wo hafi, umuriro w’ibitovu, umuriro w’ibitoke, canke umuriro w’amashamba uhinduka uva ku guturika kw’umuriro ushushe ku muhingamo ukaja ku umuriro w’umuriro w’umwotsi ukonnye mw’ijoro, urekura ibintu bibiri nyene hasi: - Imiliyaridi z’ibice vy’umwotsi bifise ubukonje (bikwegera amazi) ku sentimetero kibe, KANDI - Umwotsi w’amazi mwinshi cane utetswe mu butaka butoshe, mu mfuruka z’ivyatsi, no mu bimera vy’ivyatsi bitotahaye. 3. Ugusohoka kw’umuyaga ukonnye n’uguhindura ubushuhe: Hagati y’isaha zibiri z’ijoro n’isaha umunani z’ijoro, umuyaga ukonnye wo mw’ijoro usohoka mu bice vyo hasi cane, ivyo bikaba ari hafi y’igihe cose ibibanza vyo hasi vy’uruzi, ibidengeri vy’ibitovu, n’uburenganzira bwo guca mu nzira ndende. Iyo umwotsi ususurutse kandi ufise ubukonje bwinshi uvanze n’umuyaga ukonnye wuzuye (\(100\%\) ubukonje buringaniye, itandukaniro ry’ubushuhe \(\ge 10^\circ\text{C}\) [\(18^\circ\pentext{F}\)s]), ubukonje burakwiragira ku gice cose c’umwotsi w’umuriro w’agahomerabunwa. amamiliyoni y'utudodo dutoduto \(2\text{ gushika }5\text{ micrometer}\) kuri metero kibe dushwiragiza 99,9 kw'ijana vy'umuco uboneka mu \(1\text{ gushika }3\text{ metero}\) (\(3\text{ gushika }10\text{ amaguru}\)). 4. Ivyago vy'umuyaga bizwi cane vyo kwibuka: - Ibarabara ry’intara 55 hafi y’igisagara ca New Orleans / Ikiyaga Maurepas, muri Louisiana (23 Gitugutu 2023): Umuriro w’ibitovu wo ku nkengera y’ikiyaga uvanze n’igihu co mu gitondo kugira ngo ushireho igihu kinini cane ku biraro vy’amahasa vy’umuhanda I-55, bituma abantu benshi bapfa. bakomeretse 63. - Interstate 75 ku Paynes Prairie hafi y’i Gainesville, muri Floride (29 Mukakaro 2012): Umwotsi uva ku muriro w’ibitoke wo mu gice c’ibitoke uvanze n’igihu c’imishwarara y’ijoro, ugatuma umuntu abona ibintu bishika munsi ya metero imwe, bituma habaho ikirundo c’imiduga 25+ n’ibindi binyabiziga. - Ibarabara ry’intara ya 4 mu ntara ya Polk, muri Floride (9 Mukakaro 2008, imodoka 70) n’ibarabara ry’intara ya 75 hafi y’igisagara ca Calhoun, muri Tennessee (11 Kigarama 1990, imodoka 99).

Urugendo rwo kubona n’urugendo rwo guhagarara: Ni gute mu vy’ukuri ushobora gutwara imodoka mu gihu?¶

Benshi mu bashoferi bari mu gihu barengera amatara yabo n’aho babona. Koresha iyi mbonerahamwe ya fizike (iharuwe kuva ku nzira ndende ya AASHTO ihagaze ku nzira y'urugendo rwo kubona ukoresheje igihe c'ugutahura-ugusubiza \(2.0\text{-second}\) ku nzira y'igihu gitose) kugira ngo ubone umuvuduko munini w'umutekano ku ntambwe iyo ari yo yose yo kubona:

Deep dive 2: "Ingaruka y'inyenzi y'inyuma" n'igituma utegerezwa kuzima amatara yawe iyo uhagaze ku rutugu¶

Imwe mu mategeko ateye kubiri n’ubwenge ashirwa mu ngiro n’abajejwe umutekano wo ku nzira ndende zo muri California (CHP)** mu bihe vy’igihu co mu kiyaya ca hagati be n’abajejwe umutekano wo ku nzira ndende zo muri leta mu gihugu cose ni Itegeko ryo kuzimya amatara yo mu bitugu: - Uko "Moth Effect" ikora: Iyo umushoferi afise ubwoba kandi ahumye imbere mu gihu kinini, amaso yiwe araca mu mfuruka y'ubusa kugira ngo abone ikintu cose abona. Igihe babonye amatara abiri y’inyuma atukura canke amatara y’akaga y’umutuku akayangana imbere, baca bagenda inyuma y’ayo matara ata co bazi, biyumvira ko iyo modoka iriko iragenda mu nzira y’imiduga ikoreshwa cane. - Ivyaba iyo uhagaze ku rutugu ikirenge cawe kiri ku frein: Iyo ukwegereye ku rutugu rw’inzira ndende y’amabuye mu gihu kinini maze ukicara ng’aho amatara yawe y’imbere acana, amatara yawe y’akaga ariko arazimya, kandi ikirenge cawe kikaba kikanda ku rutugu (kimurikira amatara yawe y’amaferemi atukura cane), abashoferi ntibashobora kwegera gusa ubone amatara yawe atukura maze ugende iburyo ku rutugu winjire inyuma y’imodoka yawe ihagaze. - Uburyo bubereye bwo guhagarara vyihutirwa mu gihu kitaboneka: 1. Ivyiza ni uko ntiwigere uhagarara ku rutugu rw’inzira ndende y’amabuye; n’umanuke buhoro buhoro ku nzira ikurikira yo gusohokamwo, winjire mu kibanza co gutereramwo amavuta canke mu kibanza c’ubudandaji gifise umuco mwiza. 2. Nimba moteri yawe ihagaze canke zero visibility biguhatira kuva mu nzira aho ata nzira yo gusohoka, genda kure cane y’inzira y’amabuye uko bishoboka kwose, ku nzira y’ivyatsi canke inyuma y’uruzitiro rwo kurinda. 3. Hindukira muri Park, ukoreshe emergency/parking brake, uzime ikirenge cawe burundu ku nzira ya frein y’ikirenge, kandi uzime amatara yose yo hanze (amatara y’imbere, amatara y’inyuma, n’amatara y’akaga) rero gukurikira umuduga bica mu nzira y’umuhanda munini aho guhagarara imodoka yawe. 4. Nimba ari vyiza gusohoka ku ruhande rutari kure y’imiduga, kura umuntu wese mu modoka ihagaze maze uhagarare ku metero 15 gushika kuri 30 (amafuti 50 gushika ku 100) inyuma y’uruzitiro rwo kurinda, umurongo w’ibiti, canke umugende muremure.

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.

Icigwa ca 1: Iyo Imodoka Yawe Ihagaze Idakomeretse CANKE Ishobora Gutera Inyuma y’Igutera¶

1. NTUGUME uhagaze inyuma y'ikirundo mu nzira z'ingendo. "Iherezo ry'umurizo" ry'ikirundo ni ahantu hakora aho ikinyabiziga gikurikira c'amatoni 36 kigiye gutera mu masegonda 3.
2. Nimba imodoka yawe ishobora gutwara no gutwara: Uce wihutisha ubwo nyene ukikuza imodoka zaguye imbere yawe canke ugende cane uhereye ku nzira ndende uja ku rutugu/uruzitiro rw’ivyatsi imbere no kure y’ibisigazwa, urenge kure cane uruzitiro rwo kurinda uko bishoboka kwose.

Icigwa ca 2: Iyo Imodoka Yawe Imenetse, Ifashwe n’Ikigobe, Canke Idakora Mu Nzira¶

1. NTUKIGEZE ufungura umugozi maze usohoke ku nzira y’umuhanda munini hagati y’imiduga yamenetse. Guhagarara ku nzira y’amabuye hagati y’imiduga ibiri yamenetse mu gihu kidashobora kuboneka biratera urupfu: iyo igice c’ikamyo kikubise inyuma y’ikirundo c’amaguru metero 50 inyuma yawe, akodeyoni yose y’imiduga yamenetse itera mu 50, umuntu wese ahagaze hagati y’ibipfukisho canke akabijugunya munsi y’amapine.
2. Koresha Icuma c'Imodoka Yawe Nk'Ibirwanisho Mu gihe Ingaruka Zibandanya:
3. Guma umukanda wawe uboshe neza. Ivyumba vy’imodoka vy’ubuhinga bwa none bishobora gusenyuka, ama airbags yo mu ruhande, n’inkingi z’ivyuma vy’ibara ry’agahama zikomeye cane zishobora gufata ibintu vyinshi bitera ibilometero 60 kw’isaha bishobora kwica ubwo nyene uwuri mu modoka canke uwugenda n’amaguru ataboshe.
4. Brace for Rear-End Impact: Kanda inyuma y’umutwe wawe n’ibitugu vyawe ushire ku mutwe w’intebe (gufunga ikinogo kiri hagati y’igihanga cawe n’igitereko c’umutwe bigabanya inguvu z’ugukubitwa n’umugongo w’intanga gushika ku bice 70 kw’ijana), urabe imbere, kandi ushire ibiganza vyawe n’amaboko yawe kure y’igitereko airbag itavutse).
5. Ivyo Bibiri Bidasanzwe Aho UTEGEREZWA Gukura Imodoka Ubwo nyene:
6. Ikidasanzwe A (Umuriro canke Amavuta Ateye Akaga): Niwabona imbeya, wumva umunuko w’amavuta ya peteroli/dizeli, wumva imodoka y’amazi imenetse, canke ubonye bateri y’Imodoka y’Umuyagankuba (EV) iriko iranywa umwotsi munsi y’ikirundo, ufungure ubwo nyene, uduge usohoke mw’idirisha kure y’umuduga canke oncraor, inzitizi ya beton canke uruzitiro rwo kurinda.
7. Exception B (Uri Imodoka ya Nyuma Inyuma Cane y'Ikirundo Iruhande y'Igihome): Iyo imodoka yawe ihagaze ku mpera y'inyuma y'impanuka iruhande y'urutugu rw'inyuma kandi ufise igisimbuka gitomoye c'amasegonda 2 hejuru y'igihome imbere y'uko immediate run+0 ishika, metero (100+ feet) hanze no UPSTREAM** (inyuma werekeza aho umuduga uva, inyuma y’uruzitiro, kugira ngo ibisigazwa vy’imodoka iguruka ntibigukubite, menya ko ku kiraro giteye hejuru ata butaka buri iruhande yaco, uduge hejuru canke inyuma y’ikiraro ca beton ** up the Jerseyst barrier and run run

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.

Ibibazo bikunda kubazwa¶

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.

Amasoko yasuzumwe¶

• 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).

Inyobora zifitaniye isano¶

• Car crash: immediate steps, first aid, and highway safety
• Flash freeze and black ice driving survival
• Guhumeka umwotsi w'umuriro w'ishamba n'ivu
• Dust storms and haboob highway survival
• Car breakdown: highway shoulder survival