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A winter service vehicle (WSV), or snow removal vehicle, is a vehicle specially designed or adapted to clear thoroughfares of ice and snow. Winter service vehicles are usually based on a
dump truck A dump truck, known also as a dumping truck, dump trailer, dumper trailer, dump lorry or dumper lorry or a dumper for short, is used for transporting materials (such as dirt, gravel, or demolition waste) for construction as well as coal. A typi ...
chassis A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of an artificial object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart ...
, with adaptations allowing them to carry specially designed
snow removal Snow removal or snow clearing is the job of removing snow after a snowfall to make travel easier and safer. This is done by both individual households and by governments and institutions. De-icing and anti-icing De-icing is defined as removal ...
equipment. Many authorities also use smaller vehicles on
sidewalk A sidewalk (North American English), pavement (British English), footpath in Australia, India, New Zealand and Ireland, or footway, is a path along the side of a street, street, highway, terminals. Usually constructed of concrete, pavers, brick ...
s,
footpaths A footpath (also pedestrian way, walking trail, nature trail) is a type of thoroughfare that is intended for use only by pedestrians and not other forms of traffic such as motorized vehicles, bicycles and horses. They can be found in a wide v ...
, and
cycleway Cycling infrastructure is all infrastructure cyclists are allowed to use. Bikeways include bike paths, bike lanes, cycle tracks, rail trails and, where permitted, sidewalks. Roads used by motorists are also cycling infrastructure, except w ...
s. Road maintenance agencies and contractors in
temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...
or
polar Polar may refer to: Geography Polar may refer to: * Geographical pole, either of two fixed points on the surface of a rotating body or planet, at 90 degrees from the equator, based on the axis around which a body rotates * Polar climate, the c ...
areas often own several winter service vehicles, using them to keep the roads clear of snow and ice and safe for driving during winter. Airports use winter service vehicles to keep both aircraft surfaces, and
runway According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt concrete, as ...
s and
taxiway A taxiway is a path for aircraft at an airport connecting runways with aprons, hangars, terminals and other facilities. They mostly have a hard surface such as asphalt or concrete, although smaller general aviation airports sometimes use gravel ...
s free of snow and ice, which, besides endangering aircraft
takeoff Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff. For aircraft that take off horizontally, this usually involves starting with a t ...
and
landing Landing is the last part of a flight, where a flying animal, aircraft, or spacecraft returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called "landing", "touchdown" or ...
, can interfere with the
aerodynamics Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...
of the craft. The earliest winter service vehicles were snow rollers, designed to maintain a smooth, even road surface for
sled A sled, skid, sledge, or sleigh is a land vehicle that slides across a surface, usually of ice or snow. It is built with either a smooth underside or a separate body supported by two or more smooth, relatively narrow, longitudinal runners ...
s, although
horse-drawn A horse-drawn vehicle is a mechanized piece of equipment pulled by one horse or by a team of horses. These vehicles typically had two or four wheels and were used to carry passengers and/or a load. They were once common worldwide, but they have m ...
snowplow A snowplow (also snow plow, snowplough or snow plough) is a device intended for mounting on a vehicle, used for removing snow and ice from outdoor surfaces, typically those serving transportation purposes. Although this term is often used to re ...
s and gritting vehicles are recorded in use as early as 1862. The increase in motor car traffic and aviation in the early 20th century led to the development and popularisation of large motorised winter service vehicles.


History

Although snow removal dates back to at least the
Middle Ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
, early attempts merely involved using a
shovel A shovel is a tool used for digging, lifting, and moving bulk materials, such as soil, coal, gravel, snow, sand, or ore. Most shovels are hand tools consisting of a broad blade fixed to a medium-length handle. Shovel blades are usually made of ...
or broom to remove snow from walkways and roads. Before motorised transport, snow removal was seen as less of a concern; unpaved roads in rural areas were dangerous and bumpy, and snow and ice made the surface far smoother. Most farmers could simply replace their wagons with
sled A sled, skid, sledge, or sleigh is a land vehicle that slides across a surface, usually of ice or snow. It is built with either a smooth underside or a separate body supported by two or more smooth, relatively narrow, longitudinal runners ...
s, allowing the transport of heavy materials such as timber with relative ease. Early communities in the northern regions of the United States and Canada even used animal-drawn snow rollers, the earliest winter service vehicles, to compress the snow covering roads. The compression increased the life of the snow and eased passage for sleds. Some communities even employed snow wardens to spread or "pave" snow onto exposed areas such as bridges, to allow sleds to use these routes. However, with the increase in paved roads and the increasing size of cities, snow-paving fell out of favour, as the resultant slippery surfaces posed a danger to pedestrians and traffic. The earliest patents for snowplows date back to 1840, but there are no records of their actual use until 1862, when the city of
Milwaukee Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County. With a population of 577,222 at the 2020 census, Milwaukee is ...
began operating horse-drawn carts fitted with
snowplow A snowplow (also snow plow, snowplough or snow plough) is a device intended for mounting on a vehicle, used for removing snow and ice from outdoor surfaces, typically those serving transportation purposes. Although this term is often used to re ...
s. The horse-drawn snowplow quickly spread to other cities, especially those in areas prone to heavy snowfall. The first motorised snowplows were developed in 1913, based on truck and
tractor A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most common ...
bodies. These machines allowed the mechanisation of the snow clearing process, reducing the labor required for snow removal and increasing the speed and efficiency of the process. The expansion of the aviation industry also acted as a catalyst for the development of winter service vehicles during the early 20th century. Even a light dusting of snow or ice could cause an aeroplane to crash, so airports erected
snow fence A snow fence, similar to a sand fence, is a barrier that forces windblown, drifting snow to accumulate in a desired place. They are primarily employed to minimize the amount of snowdrift on roadways and railways. Farmers and ranchers use snow fe ...
s around airfields to prevent
snowdrift A snowdrift is a deposit of snow sculpted by wind into a mound during a snowstorm. Snowdrifts resemble sand dunes and are formed in a similar manner, namely, by wind moving light snow and depositing it when the wind has virtually stopped, u ...
s, and began to maintain fleets of vehicles to clear runways in heavy weather. With the popularisation of the
motor car A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded as t ...
, it was found that plowing alone was insufficient for removing all snow and ice from the roadway, leading to the development of gritting vehicles, which used
sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...
to accelerate the melting of the snow. Early attempts at gritting were resisted, as the salt used encouraged rusting, causing damage to the metal structures of bridges and the shoes of pedestrians. However, as the number of motoring accidents increased, the protests subsided and by the end of the 1920s, many cities in the United States used salt and sand to clear the roads and increase road safety. As
environmental awareness Environmentalism or environmental rights is a broad philosophy, ideology, and social movement regarding concerns for environmental protection and improvement of the health of the environment, particularly as the measure for this health seeks ...
increased through the 1960s and 1970s, gritting once again came under criticism due to its environmental impact, leading to the development of alternative de-icing chemicals and more efficient spreading systems.


Design

Winter service vehicles are usually based on a dump truck
chassis A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of an artificial object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart ...
, which are then converted into winter service vehicles either by the manufacturer or an aftermarket third-party. A typical modification involves the replacement of steel components of the vehicle with corrosion resistant aluminium or
fibreglass Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass clo ...
, waterproofing any exposed
electronic Electronic may refer to: *Electronics, the science of how to control electric energy in semiconductor * ''Electronics'' (magazine), a defunct American trade journal *Electronic storage, the storage of data using an electronic device *Electronic co ...
components, replacement of the stock hopper with a specially designed gritting body, the addition of a plow frame, reinforcement of the wheels, bumpers to support the heavy blade, and the addition of extra
headlamp A headlamp is a lamp attached to the front of a vehicle to illuminate the road ahead. Headlamps are also often called headlights, but in the most precise usage, ''headlamp'' is the term for the device itself and ''headlight'' is the term for ...
s, a
light bar Emergency vehicle lighting, also known as simply emergency lighting or emergency lights, is a type of Automotive lighting, vehicle lighting used to visually announce a vehicle's presence to other road users. A sub-type of emergency vehicle equip ...
, and
retroreflector A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects radiation (usually light) back to its source with minimum scattering. This works at a wide range of angle of incidence, unlike a planar mirror, ...
s for visibility. Other common changes include the replacement of the factory stock tires with
rain tire Rain tires or wet tires ("tyres" in British English, commonly shortened to wets) are special tyres used in motorsport in wet weather as opposed to a slick tyre used in dry conditions. They are very similar in many ways to the tyres found on nor ...
s or mud and snow tires and the shortening of the vehicle's
wheelbase In both road and rail vehicles, the wheelbase is the horizontal distance between the centers of the front and rear wheels. For road vehicles with more than two axles (e.g. some trucks), the wheelbase is the distance between the steering (front ...
to improve maneuverability. For smaller applications smaller trucks are used. In Canada, pickup trucks are used with snow removal operations with a blade mounted in front and optional de-icing equipment installed in the rear. Underbody scrapers are also used by some agencies and are mounted between axles, distributing plowing stresses on the chassis more evenly. In most countries, winter service vehicles usually have amber light bars, which are activated to indicate that the vehicle is operating below the local
speed limit Speed limits on road traffic, as used in most countries, set the legal maximum speed at which vehicles may travel on a given stretch of road. Speed limits are generally indicated on a traffic sign reflecting the maximum permitted speed - expres ...
or otherwise poses a danger to other traffic, either by straddling lanes or by spreading grit or de-icer. In some areas, such as the Canadian province of
Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...
, winter service vehicles use the blue flashing lights associated with emergency service vehicles, rather than the amber or orange used elsewhere. In
Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and the ...
, green flashing lights are used. Many agencies also paint their vehicles in high-contrast orange or yellow to allow the vehicles to be seen more clearly in whiteout conditions. Some winter service vehicles, especially those designed for use on footpaths or
pedestrian zone Pedestrian zones (also known as auto-free zones and car-free zones, as pedestrian precincts in British English, and as pedestrian malls in the United States and Australia) are areas of a city or town reserved for pedestrian-only use and in whi ...
s, are built on a far smaller chassis using small tractors or custom made vehicles. These vehicles are often multi-purpose, and can be fitted with other equipment such as brushes, lawnmowers or cranes—as these operations are generally unable to run during heavy snowfalls, there is generally little overlap between the different uses, reducing the size of the fleet required by the agency or contractor. Modern winter service vehicles will usually also have a
satellite navigation A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high pr ...
system connected to a
weather forecast Weather forecasting is the application of science and technology to predict the conditions of the atmosphere for a given location and time. People have attempted to predict the weather informally for millennia and formally since the 19th centu ...
feed, allowing the driver to choose the best areas to treat and to avoid areas in which rain is likely, which can wash away the grit used—the most advanced can even adapt to changing conditions, ensuring optimal gritter and plow settings.Institution of Civil Engineers, pp. 53–54 Most run on wheels, often with
snow chain Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout ...
s or studded tires, but some are mounted on
caterpillar track Continuous track is a system of vehicle propulsion used in tracked vehicles, running on a continuous band of treads or track plates driven by two or more wheels. The large surface area of the tracks distributes the weight of the vehicle b ...
s, with the tracks themselves adapted to throw the snow towards the side of the road.
Off-road Off-roading is the activity of driving or riding in a vehicle on unpaved surfaces such as sand, gravel, riverbeds, mud, snow, rocks, and other natural terrain. Types of off-roading range in intensity, from leisure drives with unmodified vehicl ...
winter service vehicles mounted on caterpillar tracks are known as
snowcat A snowcat (short for snow and caterpillar) is an enclosed-cab, truck-sized, fully tracked vehicle designed to move on snow. Major manufacturers are Pisten Bully (Germany), Prinoth (Italy) and Tucker (United States). Snow groomers A snow ...
s. Snowcats are commonly fitted with snowplows or snow groomers, and are used by
ski resort A ski resort is a resort developed for skiing, snowboarding, and other winter sports. In Europe, most ski resorts are towns or villages in or adjacent to a ski area – a mountainous area with pistes (ski trails) and a ski lift system. In North ...
s to smooth and maintain
piste A ''piste'' () is a marked ski run or path down a mountain for snow skiing, snowboarding, or other mountain sports. This European term is French
s and
snowmobile A snowmobile, also known as a Ski-Doo, snowmachine, sled, motor sled, motor sledge, skimobile, or snow scooter, is a motorized vehicle designed for winter travel and recreation on snow. It is designed to be operated on snow and ice and does not ...
runs, although they can also be used as a replacement for
chairlift An elevated passenger ropeway, or chairlift, is a type of aerial lift, which consists of a continuously circulating steel wire rope loop strung between two end terminals and usually over intermediate towers, carrying a series of chairs. They ...
s. Military winter service vehicles are heavily armoured to allow for their use in combat zones, especially in
Arctic The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...
and
mountain warfare Mountain warfare (also known as alpine warfare) is warfare in mountains or similarly rough terrain. Mountain ranges are of strategic importance since they often act as a natural border, and may also be the origin of a water source (for example, t ...
, and often based on combat bulldozers or
Humvee The High Mobility Multipurpose Wheeled Vehicle (HMMWV; colloquial: Humvee) is a family of light, four-wheel drive, military trucks and utility vehicles produced by AM General. It has largely supplanted the roles previously performed by the ori ...
s. Military winter service vehicles have been used by the United Nations,
Kosovo Force The Kosovo Force (KFOR) is a North Atlantic Treaty Organization, NATO-led international NATO peacekeeping, peacekeeping force in Kosovo. Its operations are gradually reducing until Kosovo Security Force, Kosovo's Security Force, established in 2 ...
, and the
US Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...
in Central Europe during the
Kosovo War The Kosovo War was an armed conflict in Kosovo that started 28 February 1998 and lasted until 11 June 1999. It was fought by the forces of the Federal Republic of Yugoslavia (i.e. Serbia and Montenegro), which controlled Kosovo before the war ...
, while during the
Cold War The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because the ...
, the
Royal Marines The Corps of Royal Marines (RM), also known as the Royal Marines Commandos, are the UK's special operations capable commando force, amphibious light infantry and also one of the five fighting arms of the Royal Navy. The Corps of Royal Marine ...
and
Royal Corps of Signals The Royal Corps of Signals (often simply known as the Royal Signals – abbreviated to R SIGNALS or R SIGS) is one of the combat support arms of the British Army. Signals units are among the first into action, providing the battlefield communi ...
deployed a number of tracked vehicles in
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
to patrol the
NATO The North Atlantic Treaty Organization (NATO, ; french: Organisation du traité de l'Atlantique nord, ), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states – 28 European and two No ...
border with the
Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
.


Operation

Winter service vehicles are operated by both government agencies and by private
subcontractor A subcontractor is an individual or (in many cases) a business that signs a contract to perform part or all of the obligations of another's contract. Put simply the role of a subcontractor is to execute the job they are hired by the contractor f ...
s.
Public works Public works are a broad category of infrastructure projects, financed and constructed by the government, for recreational, employment, and health and safety uses in the greater community. They include public buildings ( municipal buildings, sc ...
in areas which regularly receive snowfall usually maintain a fleet of their own vehicles or pay
retainers Retainer may refer to: * Retainer (orthodontics), devices for teeth * RFA ''Retainer'' (A329), a ship * Retainers in early China, a social group in early China Employment * Retainer agreement, a contract in which an employer pays in advance for ...
to contractors for priority access to vehicles in winter, while cities where snow is a less regular occurrence may simply hire the vehicles as needed. Winter service vehicles in the United Kingdom are the only road-going vehicles entitled to use
red diesel Fuel dyes are dyes added to fuels, as in some countries it is required by law to dye a low-tax fuel to deter its use in applications intended for higher-taxed ones. Untaxed fuels are referred to as "dyed", while taxed ones are called "clear" or "w ...
. Though the vehicles still use public highways, they are used to keep the road network operational, and forcing them to pay extra tax to do so would discourage private contractors from assisting with snow removal on public roads. Winter service vehicle drivers in the United States must hold a Class A or Class B
commercial driver's license A commercial driver's license (CDL) is a driver's license required in the United States to operate large and heavy vehicles (including trucks, buses, and trailers) or a vehicle of any size that transports hazardous materials or more than 15 p ...
. Although some agencies in some areas, such as the US state of
Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...
, allow winter service vehicle drivers to operate without any extra training, most provide supplemental lessons to drivers to teach them the most effective and safe methods of snow removal. Many require that trainee drivers ride-along with more experienced drivers, and some even operate specially designed
driving simulator Driving simulators are used for entertainment as well as in training of driver's education courses taught in educational institutions and private businesses. They are also used for research purposes in the area of human factors and medical rese ...
s, which can safely replicate dangerous winter driving conditions. Other organisations require that all staff have a recognised additional licence or certificate—the United Kingdom Highways Agency for example requires that all staff have both a
City & Guilds The City and Guilds of London Institute is an educational organisation in the United Kingdom. Founded on 11 November 1878 by the City of London and 16 livery companies – to develop a national system of technical education, the institute has ...
qualification and a supplemental Winter Maintenance Licence. Winter service vehicle drivers usually work
part-time Part-time can refer to: * Part-time job, a job that has fewer hours a week than a full-time job * Part-time student, a student, usually in higher education, who takes fewer course credits than a full-time student * Part Time Part Time (styliz ...
, before and during inclement weather only, with drivers working a 12- to 16-hour shift. Main roads are typically gritted in advance, to reduce the disruption to the network. Salt barns are provided at regular intervals for drivers to collect more grit, and bedding is provided at
road maintenance depot A road maintenance depot is a depot used by road maintenance agencies for storing works equipment and organising maintenance operations. Road maintenance depots can range in size from small sheds storing just a few pieces of equipment, to vast buil ...
s for drivers to use between shifts in heavy or prolonged storms. Weather conditions typically vary greatly depending on altitude; hot countries can experience heavy snowfall in mountainous regions yet receive very little in low-lying areas, increasing the accident rate among drivers inexperienced in winter driving. In addition, road surface temperatures can fall rapidly at higher altitudes, precipitating rapid
frost Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a gas) ...
formation. As a result, gritting and plowing runs are often prioritised in favour of clearing these mountain roads, especially at the start and end of the snow season. The hazardous roads through mountain passes pose additional problems for the large winter service vehicles. The heavy metal frame and bulky grit makes hill climbing demanding for the vehicle, so vehicles have extremely high torque
transmission Transmission may refer to: Medicine, science and technology * Power transmission ** Electric power transmission ** Propulsion transmission, technology allowing controlled application of power *** Automatic transmission *** Manual transmission *** ...
systems to provide enough power to make the climb. Furthermore, because the tight
hairpin turn A hairpin turn (also hairpin bend or hairpin corner) is a bend in a road with a very acute inner angle, making it necessary for an oncoming vehicle to turn about 180° to continue on the road. It is named for its resemblance to a bent metal hai ...
s found on mountain slopes are difficult for long vehicles to navigate, winter service vehicles for use in mountainous areas are shortened, usually from six wheels to four.


Equipment


De-icer

De-icers spray heated de-icing fluid, most often using
propylene glycol Propylene glycol (IUPAC nomenclature, IUPAC name: propane-1,2-diol) is a viscous, colorless liquid, which is nearly odorless but possesses a faintly sweet taste. Its chemical formula is CH3CH(OH)CH2OH. Containing two Alcohol (chemistry), alcoho ...
(formerly
ethylene glycol Ethylene glycol (IUPAC name: ethane-1,2-diol) is an organic compound (a vicinal diol) with the formula . It is mainly used for two purposes, as a raw material in the manufacture of polyester fibers and for antifreeze formulations. It is an odo ...
was used), onto icy surfaces such as the bodies of aircraft and road surfaces. These prevent ice from forming on the body of the aircraft while on the ground. Ice makes the surface of the wings rougher, reducing the amount of
lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobile ...
they provide while increasing drag. The ice also increases the weight of the aircraft and can affect its balance. Aircraft de-icing vehicles usually consist of a large
tanker truck Tanker may refer to: Transportation * Tanker, a tank crewman (US) * Tanker (ship), a ship designed to carry bulk liquids ** Chemical tanker, a type of tanker designed to transport chemicals in bulk ** Oil tanker, also known as a petroleum tanke ...
, containing the concentrated de-icing fluid, with a water feed to dilute the fluid according to the ambient temperature. The vehicle also normally has a
cherry picker An aerial work platform (AWP), also known as an aerial device, elevating work platform (EWP), cherry picker, bucket truck or mobile elevating work platform (MEWP) is a mechanical device used to provide temporary access for people or equipment t ...
crane, allowing the operator to spray the entire aircraft in as little time as possible; an entire
Boeing 737 The Boeing 737 is a narrow-body aircraft produced by Boeing at its Renton Factory in Washington. Developed to supplement the Boeing 727 on short and thin routes, the twinjet retains the 707 fuselage width and six abreast seating with two un ...
can be treated in under 10 minutes by a single de-icing vehicle. In road snow and ice control,
brine Brine is a high-concentration solution of salt (NaCl) in water (H2O). In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawater, on the lower end of that of solutions used for br ...
is often used as an anti-icer rather than a de-icer. A vehicle carries a tank of brine, which is sprayed on the road surface before or at the onset of the storm. This keeps snow and ice from adhering to the surface and makes mechanical removal by plows easier. Solid salt is also wetted with brine or other liquid deicer. This speeds de-icing action and helps keep it from bouncing off the pavement into the gutter or ditch. Brine acts faster than solid salt and does not require compression by passing traffic to become effective. The brine is also more environmentally friendly, as less salt is required to treat the same length of road. Airport runways are also de-iced by sprayers fitted with long spraying arms. These arms are wide enough to cross the entire runway, and allow de-icing of the entire airstrip to take place in a single pass, reducing the length of time that the runway is unavailable.


Front-end loader

Front-end loaders are commonly used to remove snow especially from sidewalks, parking lots, and other areas too small for using snowplows and other heavy equipment. They are sometimes used as snowplows with a snowplow attachment but commonly have a bucket or snowbasket, which can also be used to load snow into the rear compartment of a snowplow or dump truck. Front end loaders with large box-like front end attachment are used to clear snow in parking lots in malls and other institutions.


Gritter

A gritter, also known as a sander, salt spreader or salt truck, is found on most winter service vehicles. Indeed, the gritter is so commonly seen on winter service vehicles that the terms are sometimes used synonymously. Gritters are used to spread grit (usually
rock salt Halite (), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pi ...
), onto roads. The grit is stored in the large hopper on the rear of the vehicle, with a wire mesh over the top to prevent foreign objects from entering the spreading mechanism and hence becoming jammed. The salt is generally spread across the roadway by an
impeller An impeller or impellor is a rotor used to increase the pressure and flow of a fluid. It is the opposite of a turbine, which extracts energy from, and reduces the pressure of, a flowing fluid. In pumps An impeller is a rotating component ...
, attached by a
hydraulic drive system Hydraulic machines use liquid fluid power to perform work. Heavy construction vehicles are a common example. In this type of machine, hydraulic fluid is pumped to various hydraulic motors and hydraulic cylinders throughout the machine and b ...
to a small onboard engine. However, until the 1970s, the grit was often spread manually using shovels by men riding on the back of the truck, and some older spreading mechanisms still require grit be manually loaded into the impeller from the hopper.Pearson, p. 444–445 Salt reduces the melting point of ice by
freezing-point depression Freezing-point depression is a drop in the minimum temperature at which a substance freezes, caused when a smaller amount of another, non- volatile substance is added. Examples include adding salt into water (used in ice cream makers and for ...
, causing it to melt at lower temperatures and run off to the edge of the road, while sand increases traction by increasing
friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of t ...
between car
tire A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a Rim (wheel), wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide Traction (engineering), t ...
s and roadways. The amount of salt dropped varies with the condition of the road; to prevent the formation of light ice, approximately is dropped, while thick snow can require up to of salt, independent of the volume of sand dropped. The grit is sometimes mixed with
molasses Molasses () is a viscous substance resulting from refining sugarcane or sugar beets into sugar. Molasses varies in the amount of sugar, method of extraction and age of the plant. Sugarcane molasses is primarily used to sweeten and flavour foods ...
to help adhesion to the road surface. However, the sweet molasses often attracts livestock, who lick the road. Gritters are among the winter service vehicles also used in airports, to keep runways free of ice. However, the salt normally used to clear roads can damage the
airframe The mechanical structure of an aircraft is known as the airframe. This structure is typically considered to include the fuselage, undercarriage, empennage and wings, and excludes the propulsion system. Airframe design is a field of aerospa ...
of aircraft and interferes with the sensitive navigation equipment. As a result, airport gritters spread less dangerous
potassium acetate Potassium acetate (CH3COOK) is the potassium salt of acetic acid. It is a hygroscopic solid at room temperature. Preparation It can be prepared by treating a potassium-containing base such as potassium hydroxide or potassium carbonate with acetic ...
or
urea Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important r ...
onto the runways instead, as these do not corrode the aircraft or the airside equipment. Gritters can also be used in hot weather, when temperatures are high enough to melt the
bitumen Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term a ...
used in
asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term a ...
. The grit is dropped to provide a protective layer between the road surface and the tires of passing vehicles, which would otherwise damage the road surface by "plucking out" the bitumen-coated Aggregate (composite), aggregate from the road surface.


Snow blower

Snow blowers, also known as rotating snowplows or snow cutters, can be used in place of snowplows on winter service vehicles. A snow blower consists of a rapidly spinning auger which cuts through the snow, forcing it out of a funnel attached to the top of the blower. Snow blowers typically clear much faster than plows, with some clearing in excess of of snow per hour, and can cut through far deeper snow drifts than a snowplow can. In addition, snow blowers can remove snow from the roadway completely, rather than piling it at the side of the road, making passage easier for other road users and preventing the windrow from blocking driveways.


Jet-powered snow blower

Some railroads occasionally use air-blowing machines, each powered by a jet engine, to clear snow from tracks and switches. In addition to physically blowing snow with the force of the air, they melt recalcitrant precipitation with exhaust temperatures over . Approximately 100 are believed to have been manufactured in the 1960s, 1970s, and 1980s; they are used so rarely that they are generally maintained indefinitely rather than being replaced. For example, in the Boston area the MBTA uses two model RP-3 Portec RMC Hurricane Jet Snow Blowers, nicknamed "Snowzilla", to clear heavy snows from the Ashmont–Mattapan High Speed Line and Wellington (MBTA station), Wellington Yard. The jet snow blowers can be faster and gentler than conventional removal methods, but they consume a large amount of fuel.


Snow groomer

A snow groomer is a machine designed to smooth and compact the snow, rather than removing it altogether. Early snow groomers were used by residents of rural areas to compress the snow close to their homes, and consisted of a heavy Roller (agricultural tool), roller hauled by oxen which compacted the snow to make a smooth surface for sledging. With the invention of the motor car, snow groomers were replaced by snowplows and snow blowers on public thoroughfares, but remained in use at
ski resort A ski resort is a resort developed for skiing, snowboarding, and other winter sports. In Europe, most ski resorts are towns or villages in or adjacent to a ski area – a mountainous area with pistes (ski trails) and a ski lift system. In North ...
s, where they are used to maintain smooth, safe trails for various wintersports, including skiing, snowboarding and snowmobiling. Snow groomers remained unchanged throughout the 20th century, with most consisting of heavy roller which could be attached to a tractor or
snowcat A snowcat (short for snow and caterpillar) is an enclosed-cab, truck-sized, fully tracked vehicle designed to move on snow. Major manufacturers are Pisten Bully (Germany), Prinoth (Italy) and Tucker (United States). Snow groomers A snow ...
and then hauled across the area to be groomed. The development of more advanced electronic systems in the 1980s allowed manufacturers to produce snow groomers which could work on and replicate a much wider range of terrains, with the most modern even able to produce half-pipes and Mini ramp, ramps for snowboarding. Snow groomers are also used in conjunction with snow cannons, to ensure that the snow produced is spread evenly across the resort. However, snow groomers have a detrimental effect on the environment within the resort. Regular pressure from the grooming vehicle increases the infiltration (hydrology), infiltration rate of the soil while decreasing the field capacity. This increases the rate at which water can soak through the soil, making it more prone to erosion.


Snow melter

A snow-melting vehicle works by scooping snow into a melting pit located in a large tank at the rear of the vehicle. Around the melting pit is a thin jacket full of warm water, heated by a powerful burner. The gases from the burner are bubbled through the water, causing some of the heated water to spill over into the melting pit, melting the snow instantly. The meltwater is discharged into the storm drains. Because they have to carry the large water tank and fuel for the burner, snow melting machines tend to be much larger and heavier than most winter service vehicles, at around , with the largest being hauled by semi-trailer truck, semi-trailer tractor units. In addition, the complicated melting process means that snow melting vehicles have a much lower capacity than the equivalent plow or blower vehicle; the largest snow melter can remove 500 metric tons of snow per hour, compared to the 5,000 metric tons per hour capacity of any large snow blower. Snow melters are in some ways more environmentally friendly than gritters, as they do not spray hazardous materials, and pollutants from the road surface can be separated from the meltwater and disposed of safely. In addition, because the snow is melted on board, the costs of transporting snow from the site are eliminated. On the other hand, snow melting can require large amounts of energy, which has its own costs and environmental impact.


Snowplow

Many winter service vehicles can be fitted with snowplows, to clear roads which are blocked by deep snow. In most cases, the plows are mounted on hydraulics, hydraulically actuated arms, allowing them to be raised, lowered, and angled to better move snow. Most winter service vehicles include either permanently fixed plows or plow frames: 75% of the UK's Highways Agency vehicles include a plow frame to which a blade can be attached. Winter service vehicles with both a plow frame and a gritting body are known as "all purpose vehicles", and while these are more efficient than using dedicated vehicles, the weight of the hopper often decreases the range of the vehicle. Therefore, most operators will keep at least a few dedicated plowing vehicles in store for heavy storms. In the event that specially designed winter service vehicles are not available for plowing, other service or construction vehicles can be used instead: among those used by various authorities are graders, bulldozers, skid loaders, pickup trucks and rubbish trucks. Front-end loaders can also be used to plow snow. Either a snowplow attachment can be mounted on the loader's arm in place of the bucket, or the bucket or snowbasket can be used to load snow into the rear compartment of a snowplow or dump truck, which then hauls it away. Snowplows are dangerous to overtaking, overtake; often, the oncoming lane may not be completely free of snow. In addition, the plow blade causes considerable spray of snow on both sides, which can obscure the vision of other road users.


Snow sweeper

A snow sweeper uses brushes to remove thin layers of snow from the pavement surface. Snow sweepers are used after plowing to remove any remaining material missed by the larger vehicles in areas with very low snow-tolerance, such as airport runways and racing tracks, as the flexible brushes follow the terrain better than the rigid blades of snowplows and snow blowers. These brushes also allow the vehicle to be used on the tactile tiles found at traffic lights and tram stops, without damaging the delicate surface. Unlike other winter service vehicles, snow sweepers do not compress the snow, leaving a rough, high friction, surface behind them. This makes snow sweepers the most efficient method of snow removal for snow depths below . Snow deeper than this, however, can clog the brushes, and most snow sweepers cannot be used to clear snow deeper than . A more advanced version of the snow sweeper is the jet sweeper, which adds an air-blower just behind the brushes, in order to blow the swept snow clear of the pavement and prevent the loosened snow from settling.


Surface friction tester

The surface friction tester is a small fifth wheel attached to a hydraulic system mounted on the rear axle of the vehicle, used to measure road slipperiness. The wheel, allowed to roll freely, is slightly Yaw angle, turned relative to the ground so that it partially slides. Sensors attached to the axis of the wheel calculate the friction between the wheel and the pavement by measuring the torque produced by the rotation of the wheel. Surface friction testers are used at airports and on major roadways before ice formation or after snow removal. The vehicle can relay the surface friction data back to the control centre, allowing gritting and clearing to be planned so that the vehicles are deployed most efficiently. Surface friction testers often include a water spraying system, to simulate the effects of rain on the road surface before the rain occurs. The sensors are usually mounted to small Compact car, compact or estate cars or to a small Trailer (vehicle), trailer, rather than the large trucks used for other winter service equipment, as the surface friction tester works best when attached to a lightweight vehicle.


Materials

To improve traction and melt ice or snow, winter service vehicles spread granular or liquid ice-melting chemicals and grit, such as sand or gravel. The most common chemical is rock salt, which can melt snow at low temperatures but has some unwanted side effects. If the salt concentration becomes high enough, it can be toxic to plant and animal life and greatly accelerate corrosion of metals, so operators should limit gritting to an absolute minimum. The dropped salt is eventually washed away and lost, so it may not be reused or collected after gritting runs. By contrast, the insoluble sand can be collected and recycled by Street sweeper, street sweeping vehicles and mixed with new salt crystals to be reused in later batches of grit. Sea salt may not be used, as it is too fine and dissolves too quickly, so all salt used in gritting comes from salt mines, a renewable, non-renewable source. As a result, some road maintenance agencies have networks of ice prediction stations, to prevent unnecessary gritting, which not only wastes salt but can also damage the environment and disrupt traffic. The U.S. state of Oregon uses magnesium chloride, a relatively cheap chemical similar in snow-melting effects to sodium chloride, but less reactive, while New Zealand uses calcium magnesium acetate, which avoids the environmentally harmful chloride ion altogether. Urea is sometimes used to grit suspension bridges, as it does not corrode iron or steel at all, but urea is less effective than salt and can cost up to seven times more, weight-for-weight. In some areas of the world, including Berlin, Germany, dropping salt is prohibited altogether except on the highest-risk roads; plain sand without any melting agents is spread instead. While this may protect the environment, it is more labour-intensive, as more gritting runs are needed; because the sand is insoluble, it tends to accumulate at the sides of the road, making it more difficult for buses to pull in at bus stops. Grit is often mixed with hydrate, hydrous sodium ferrocyanide as an anticaking agent which, while harmless in its natural form, can undergo photodissociation in strong sunlight to produce the extremely toxic chemical hydrogen cyanide. Although sunlight is generally not intense enough to cause this in polar and temperate regions, salt deposits must kept as far as possible from waterways to avert the possibility of cyanide-tainted Surface runoff, runoff water entering fishery, fisheries or farms.Pearson, p. 435 Gritting vehicles are also dangerous to overtaking, overtake; as grit is scattered across the entire roadway, loose pieces can damage the paintwork and windows of passing cars. Loose salt does not provide sufficient traction for motorcycles, which can lead to skidding, especially around corners.


See also

* Snow emergency * Snowplow * Snow removal * Wedge plow


References


Further reading

* * * * * * * * * * *


External links

;General
Snow removal site links
National Snow and Ice Data Center
Real Time update for Gritted Roads in UK
;Road snow removal
Driving in adverse weather conditions
The Highway Code
Winter Service
The Highways Agency
Photograph: Road rolling-about 1885-under direction of James Little, overseer of highways, Calumet Township, Michigan, US
The Bentley Historical Library
Winter driving advice
;Airport snow removal

Dresden Airport
Snow clearance at Vnukovo International Airport
Vnukovo International Airport {{DEFAULTSORT:Winter Service Vehicle Engineering vehicles Road safety Snowplows Snow removal Trucks Articles containing video clips