Strategies for reducing vehicular accidents in thick fog|Earth Science – Geography
Introduction
Fog is a sure sort of cloud that individuals often encounter. Whereas fog varies in
visibility and there are various kinds of fog as nicely, similar to advection and radiation fog.
Though it’d seem innocent, it may be a lethal hazard and creates harmful highway
situations. When encountering, or driving by fog, it seems as a thick white cloud that
impacts visibility. Yearly fog causes massive accidents that may be deadly because of the thickness of
fog. The California Division of Transportation has developed methods in an effort to cut back
the variety of fog-associated accidents that happen every year with combined outcomes.
Varieties of Fog
In keeping with the Nationwide Geographic, fog types when water vapor condenses, throughout
which, molecules of water mix to kind small droplets of liquid water that hold in the air.
This course of permits fog to be seen. (“Fog”, 2012). The various kinds of fog embrace advection
fog, radiation fog, valley fog and freezing fog. Radiation fog types in the course of the night time when skies
are clear (Walker, 2003). The warmth close to the bottom cools after which stabilizes which causes the
condensation of the water vapor and in flip causes the fog to kind. In different phrases, the warmth that
is absorbed by the floor in the course of the day is then radiated into the air at night time, inflicting the
condensation (“Fog”, 2012). The skies should stay clear with minimal to mild winds as a result of
robust winds can forestall radiation fog from forming because of the combination of air (Ahrens and
Samson, 97). There’s additionally a kind of radiation fog that happens in the Central Valley known as tule
fog. This fog is also called valley fog. Tule fog types because of the mixture of cool air from
the Pacific, clear skies and lightweight winds which all outcome in thick fog in the Valley from late fall to
early spring (“Fog Security in Radiation Fog,” 2001). One of many methods radiation fog dissipates
happens when daylight pierces the fog and warms the bottom which in flip warms the air (Ahrens
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and Samson, 98). When the fog is just too thick and doesn’t dissipate, it is called excessive fog
(Ahrens and Samson, 98).
Advection fog types when heat and moist air passes over a cool floor. The water
vapor condenses as the nice and cozy air touches the chilly floor, similar to cool ocean waters (“Fog,”
2012). This fog is seen in the summer season alongside the Pacific Coast (Ahrens and Samson, 98). If it
weren’t for advection fog, the redwood timber alongside the coast in California would have
difficulties surviving. (Ahrens and Samson, 98). That is because of the moisture in the fog getting
collected by branches which in flip waters the redwoods because the droplets drip down. Moreover,
in order for advection fog to happen, winds are wanted for the nice and cozy air to maneuver over the colder
floor. Nonetheless, for radiation fog, no winds are wanted for the fog to kind.
The North Pacific anticyclone, also called the Pacific Excessive, and coastal upwelling,
each mix to create prime situations for fog to kind in California throughout spring and summer season
months (Gilliam, 2002). Cool air over an ocean floor is called the Pacific Excessive and it’s
discovered between San Francisco and Hawaii (Gilliam, 2002). Upwelling is a course of in which chilly
ocean water surges to the floor (Ahrens and Samson, 78). The winds from the Pacific Excessive
trigger the ocean upwelling. Because the air accumulates moisture, it stays nonetheless as a vapor and as soon as it
encounters the chilly upwelled waters, the vapor cools off to kind small droplets by attaching
itself to small salt particles (Gilliam, 2002). Sea salt particles are hygroscopic nuclei which
signifies that the particles are water looking for (Ahrens & Samson, 97). Moreover, as fog types,
extra droplets seem on hygroscopic nuclei which are out there. Different forms of hygroscopic nuclei
embrace pollution which additionally trigger fog to kind in highways, airports and seaports (Hung and
Liaw, 268).
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One other sort of harmful fog is freezing fog. The sort of fog isn’t frozen so long as
nothing is touching it. Nonetheless, as soon as it comes into contact with any object, the fog does freeze if
the temperature is under the freezing level of 32 levels F (Shepard, 2017). In keeping with the
Nationwide Climate Service, the water droplets in the freezing fog should be “tremendous cooled” (“Fog
Security in Freezing Fog”). Moreover, the sort of fog is especially harmful as a result of it may
trigger issues whereas driving or whereas in a airplane as a result of it’ll tremendously cut back visibility. Bushes
and branches develop into coated with ice. Moreover, freezing ice may cause black ice on roads.
The sort of ice is troublesome to note; due to this fact, it’s best to make use of precaution when driving on icy
roads.
Foggiest Locations in the US
Fog can kind at anywhere so long as the situations are in place. Nonetheless, some locations
are foggier than others such because the Golden Gate Bridge in California. Fog is thought to envelop
the bridge making it fully disappear inside the fog. The fog in San Francisco is advection
fog due to the nice and cozy moist air going over the chilly waters of the Pacific coast. One of many
foggiest locations in the US is Mount Washington in New Hampshire. This space is thought
to be foggy throughout 90% of summer season days. Within the winter, Mount Washington produces freezing fog
and visibility goes all the way down to about 100 ft. (“Well being & Security Necessities”). One other foggy place
in the US is Cape Disappointment in Washington. Cape Disappointment experiences
fog greater than 100 days out of the 12 months (Judd, 2012). Level Reyes is one other vastly foggy location
in the US, close to San Francisco in California. In keeping with the Nationwide Park Service,
this fog can cowl the ocean for over 50 miles off the shore and may fully cowl the seashores
(“Climate”). Fog is the heaviest throughout July, August and September at Level Reyes.
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Fog-Associated Accidents
Lack of visibility resulting from fog is the reason for many vehicular accidents. The quantity of
harm fog may cause is corresponding to the monetary and human value of storms like tornados
(Value, 168) This reveals that fog is harmful and may trigger numerous harm. Per Ahmed et al.
over 22% of crashes in the U.s.a. in 2001 had been resulting from climate associated visibility issues
similar to fog. Between 2002 and 2007, Florida had 299 deadly crashes resulting from fog. Florida was additionally
among the many prime three states with probably the most crashes resulting from fog together with California and Texas
(Ahmed et al.) These findings are supported by a examine performed by Abdel-Aty et al. which
discovered that foggy and smoky situations are way more harmful than clear visibility situations
(Abdel-aty et al.). These accidents happen like a series response. One automotive will rear finish one automotive due
to the shortage of visibility and the oncoming automobiles will proceed to crash into one another as they brake
too late. Yearly pileups are reported throughout the nation which reveals that fog actually does
trigger harm. Fog may cowl roads in patches which signifies that automobiles may be driving in clear
situations and all of the sudden their visibility drops.
Early in 2017, there was a fifty-automotive pile-up in Kings-County, California resulting from foggy
situations (Johnson). The crashes continued alongside a 4 mile stretch of highway, nevertheless, there
had been no fatalities. On December 11th, 1990, heavy fog triggered a lethal pile-up in Tennessee. 99
automobiles had been concerned in the lethal crash that left a dozen folks lifeless (Lakin). This crash is thought
as one of many deadliest crashes resulting from fog associated situations. In 2008, 4 folks had been killed in a
70-car pile-up in Florida on Interstate four. The fog had decreased visibility to the purpose the place
rescuers needed to stroll from automotive to automotive, wanting for injured folks. The crashes and pileups
stretched out 15 miles by interstate four. The New York Instances additionally reported on a 100-car pile-
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up in Fresno that killed two folks in November of 2007 (“100 Vehicles Collide on a Fog-Cloaked
Route”).
Strategies to stop fog-associated fatalities
The Division of Transportation has employed many methods to cut back fatalities due
to fog. The California Division of Transportation, also called Caltrans, is accountable for
managing state freeway programs. In 1991, Caltrans and the California Freeway Patrol (CHP)
started a program known as “Operation Fog” (“Operation Fog”). On the web site for Operation Fog,
there are 9 security ideas included for driving in foggy situations. The primary is to cut back speeds whereas
driving in order to have protected stopping distances (“Operation Fog”). Different ideas embrace driving
with headlights on low-beam, avoiding busy intersections, and listening for oncoming visitors
(“Operation Fog”). Most of the following tips are helpful, nevertheless, avoiding busy intersections isn’t
one thing everybody can do, particularly if they’re making an attempt to achieve a selected vacation spot and are in
a rush. The web site additionally doesn’t present reasoning for the information Caltrans gives. The general public
ought to know why they’re being informed to comply with ideas. For instance, utilizing excessive-beams in the fog
will mirror the sunshine again inflicting even worse visibility. Due to this fact, you will need to use low-
beams. Moreover, driving with open home windows will permit one to listen to the oncoming visitors,
even when it’s not seen. The web site additionally gives a video on fog security. Within the video, John
Castro, a transportation electrical engineer, explains that Caltrans has automated messages that
present up alongside strategic locations alongside highways. These messages are triggered when visibility
falls under 500 toes and shows messages that warns drivers to decelerate. This can be a helpful
technique as a result of it lets drivers know to anticipate fog and modify their driving speeds. This may
profit drivers who may not have been conscious of situations earlier than happening the highway.
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Caltrans additionally has a web site titled “Fog College.” This interactive web site additionally gives
tips about driving in fog, nevertheless, it additionally gives data on new fog know-how, such because the
Fog Detection and Warning System (FDWS). In keeping with the Division of Transportation,
tule fog is extremely accountable for most climate-associated accidents in California (“Greatest Practices
for Street Climate Administration”). Due to this fact, Caltrans constructed the FDWS alongside a 13 mile stretch of
the California Freeway 99. The system makes use of a mix of sensors and cameras and lets
drivers learn about fog situations and when to decelerate resulting from visitors.
Having indicators that alerts motorists of driving situations saves lives. Nonetheless, this might
probably pose an issue if situations are so foggy that the indicators should not readable.
Moreover, even with these methods in place massive pile-ups nonetheless happen to today. The Fog
College web site lists that there have been 46 fatalities, 1141 accidents, and 1503 collisions in
California (“Fog College”). It doesn’t point out the 12 months the statistics are from; nevertheless, they
present the sheer quantity of injury fog may cause. Nonetheless, there may be solely a lot Caltrans can
do to stop fog-associated accidents. The one solution to absolutely forestall accidents is to stop drivers
from driving in any respect, maybe by closing foggy roads and directing visitors by various
routes. Nonetheless, that’s not a possible challenge as it might lengthen driving occasions for these in a
hurry. Individuals can select to take various routes if they want. The most effective Caltrans can do is provide
security tricks to the general public. All it takes is for one automotive to make a mistake to set off a series response.
Lately, mass textual content messages have been despatched out to the general public with extreme climate alerts. These
messages assure that the general public is aware of vital climate occasions. That is particularly useful
to individuals who don’t watch morning information or don’t go on social media. Nonetheless, Caltrans
has unfold tricks to a wider viewers by using social media. The Federal Communications
Fee (FCC) has performed one thing comparable by establishing the 511 system in 2000 (“511”).
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This visitors system gives actual-time climate and visitors data. To entry the 511 system
in California, the general public can merely dial 511 on their telephones to listen to of present climate
situations. They will additionally obtain the Caltrans smartphone app, Quickapp to take a look at climate
updates (“511 Visitors Programs”). There are additionally totally different social media accounts for sure
areas in California. The 511 system seems to be the best solution to get data out into
the general public the quickest.
Conclusion
Fog can range in phrases of forms of fog and has various ranges of visibility. California
experiences two predominant forms of fog, advection and radiation fog. Inside California, the Central
Valley experiences tule fog from late fall to early spring. San Francisco is well-known for the
advection fog that envelops the Golden Gate Bridge and is among the many foggiest locations in the
United States. Fog poses a lethal risk to motorists throughout foggy climate. Though there isn’t any
solution to do away with fog, to fight fog-associated accidents, Caltrans has developed methods to
cut back these accidents with various ranges of success.
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