Gritter
Encyclopedia
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...
and snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
. Winter service vehicle
Vehicle
A vehicle is a device that is designed or used to transport people or cargo. Most often vehicles are manufactured, such as bicycles, cars, motorcycles, trains, ships, boats, and aircraft....
s are usually based on dump truck
Dump truck
A dump truck is a truck used for transporting loose material for construction. A typical dump truck is equipped with a hydraulically operated open-box bed hinged at the rear, the front of which can be lifted up to allow the contents to be deposited on the ground behind the truck at the site of...
chassis
Chassis
A chassis consists of an internal framework that supports a man-made object. It is analogous to an animal's skeleton. An example of a chassis is the underpart of a motor vehicle, consisting of the frame with the wheels and machinery.- Vehicles :In the case of vehicles, the term chassis means the...
, with adaptations allowing them to carry specially designed snow removal
Snow removal
Snow removal 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:...
equipment. Many authorities also use smaller vehicles on sidewalk
Sidewalk
A sidewalk, or pavement, footpath, footway, and sometimes platform, is a path along the side of a road. A sidewalk may accommodate moderate changes in grade and is normally separated from the vehicular section by a curb...
s, footpaths
Trail
A trail is a path with a rough beaten or dirt/stone surface used for travel. Trails may be for use only by walkers and in some places are the main access route to remote settlements...
, and cycleways. Road maintenance agencies and contractors in temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
or polar
Polar climate
Regions with a polar climate are characterized by a lack of warm summers . Regions with polar climate cover over 20% of the Earth. The sun shines 24 hours in the summer, and barely ever shines at all in the winter...
areas often own several winter service vehicles, using them to keep the roads clear of snow and ice
Road debris
Road debris, a form of road hazard, is debris on or off a road. Road debris includes substances, materials, and objects that are foreign to the normal roadway environment...
and safe for driving during winter. Airport
Airport
An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport...
s use winter service vehicles to keep both aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
surfaces, and runway
Runway
According to ICAO a runway is a "defined rectangular area on a land aerodrome prepared for the landing and take-off of aircraft." Runways may be a man-made surface or a natural surface .- Orientation and dimensions :Runways are named by a number between 01 and 36, which is generally one tenth...
s and taxiway
Taxiway
A taxiway is a path on an airport connecting runways with ramps, hangars, terminals and other facilities. They mostly have hard surface such as asphalt or concrete, although smaller airports sometimes use gravel or grass....
s free of snow and ice, which, besides endangering aircraft takeoff
Takeoff
Takeoff is the phase of flight in which an aerospace vehicle goes from the ground to flying in the air.For horizontal takeoff aircraft this usually involves starting with a transition from moving along the ground on a runway. For balloons, helicopters and some specialized fixed-wing aircraft , no...
and landing
Landing
thumb|A [[Mute Swan]] alighting. Note the ruffled feathers on top of the wings indicate that the swan is flying at the [[Stall |stall]]ing speed...
, can interfere with the aerodynamics
Aerodynamics
Aerodynamics is a branch of dynamics concerned with studying the motion of air, particularly when it interacts with a moving object. Aerodynamics is a subfield of fluid dynamics and gas dynamics, with much theory shared between them. Aerodynamics is often used synonymously with gas dynamics, with...
of the craft.
The earliest winter service vehicles were snow rollers, designed to maintain a smooth, even road surface for sled
Sled
A sled, sledge, or sleigh is a land vehicle with a smooth underside or possessing a separate body supported by two or more smooth, relatively narrow, longitudinal runners that travels by sliding across a surface. Most sleds are used on surfaces with low friction, such as snow or ice. In some cases,...
s, although horse-drawn
Horse-drawn vehicle
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...
snowplow
Snowplow
A snowplow is a device intended for mounting on a vehicle, used for removing snow and ice from outdoor surfaces, typically those serving transportation purposes...
s and gritting vehicles are recorded in use as early as 1862. The increase in motor car traffic and aviation
Aviation
Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Aviation is derived from avis, the Latin word for bird.-History:...
in the early 20th century led to the development and popularisation of large motorised winter service vehicles.
History
Middle Ages
The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...
, early attempts merely involved using a shovel
Shovel
A shovel is a tool for digging, lifting, and moving bulk materials, such as soil, coal, gravel, snow, sand, or ore. Shovels are extremely common tools that are used extensively in agriculture, construction, and gardening....
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
Sled
A sled, sledge, or sleigh is a land vehicle with a smooth underside or possessing a separate body supported by two or more smooth, relatively narrow, longitudinal runners that travels by sliding across a surface. Most sleds are used on surfaces with low friction, such as snow or ice. In some cases,...
s, allowing the transport of heavy materials such as timber with relative ease. Early communities in the northern regions of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
even used animal-drawn
Animal-powered transport
Animal-powered transport is a broad category of the human use of non-human working animals for the movement of people and goods....
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
Pavement (material)
Road surface or pavement is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past cobblestones and granite setts were extensively used, but these surfaces have mostly been replaced by asphalt or concrete. Such...
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 patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
s for snowplows date back to 1840, but there are no records of their actual use until 1862, when the city of Milwaukee began operating horse-drawn carts fitted with snowplow
Snowplow
A snowplow is a device intended for mounting on a vehicle, used for removing snow and ice from outdoor surfaces, typically those serving transportation purposes...
s. The horse-drawn snowplow quickly spread to other cities, especially those in areas prone to heavy snowfall.
Tractor
A tractor is a vehicle specifically designed to deliver a high tractive effort at slow speeds, for the purposes of hauling a trailer or machinery used in agriculture or construction...
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
Aviation
Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Aviation is derived from avis, the Latin word for bird.-History:...
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
Snow fence
A snow fence is a structure, similar to a sand fence, that forces 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 may use temporary snow fences to create large drifts in basins for a...
s around airfields to prevent snowdrift
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 is slowed, usually against a stationary object. Snow normally crests and slopes...
s, and began to maintain fleets of vehicles to clear runways in heavy weather.
With the popularisation of the motor car, it was found that plowing alone was insufficient for removing all snow and ice from the roadway, leading to the development of gritting vehicles
Gritter
A winter service vehicle , or snow removal vehicle, is used to clear thoroughfares of ice and snow. Winter service vehicles are usually based on dump truck chassis, with adaptations allowing them to carry specially designed snow removal equipment. Many authorities also use smaller vehicles on...
, which used sodium chloride
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
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
Environmentalism is a broad philosophy, ideology and social movement regarding concerns for environmental conservation and improvement of the health of the environment, particularly as the measure for this health seeks to incorporate the concerns of non-human elements...
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
Chassis
A chassis consists of an internal framework that supports a man-made object. It is analogous to an animal's skeleton. An example of a chassis is the underpart of a motor vehicle, consisting of the frame with the wheels and machinery.- Vehicles :In the case of vehicles, the term chassis means the...
, which are then converted into winter service vehicles either by the manufacturer or an aftermarket
Aftermarket (automotive)
The automotive aftermarket is the secondary market of the automotive industry, concerned with the manufacturing, remanufacturing, distribution, retailing, and installation of all vehicle parts, chemicals, tools, equipment and accessories for light and heavy vehicles, after the sale of the...
third-party. A typical modification involves the replacement of steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
components of the vehicle with corrosion resistant aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
or fibreglass, waterproofing any exposed electronic
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
components, replacement of the stock hopper with a specially designed gritting body, the addition of a plow frame, reinforcement of the wheel
Wheel
A wheel is a device that allows heavy objects to be moved easily through rotating on an axle through its center, facilitating movement or transportation while supporting a load, or performing labor in machines. Common examples found in transport applications. A wheel, together with an axle,...
s, bumpers to support the heavy blade, and the addition of extra headlamp
Headlamp
A headlamp is a lamp, usually attached to the front of a vehicle such as a car or a motorcycle, with the purpose of illuminating the road ahead during periods of low visibility, such as darkness or precipitation. Headlamp performance has steadily improved throughout the automobile age, spurred by...
s, a light bar
Light bar
Emergency vehicle lighting refers to any of several visual warning devices, which may be known as light bars or beacons, fitted to a vehicle and used when the driver wishes to convey to other road users the urgency of their journey, to provide additional warning of a hazard when stationary, or in...
, and retroreflector
Retroreflector
A retroreflector is a device or surface that reflects light back to its source with a minimum scattering of light. An electromagnetic wave front is reflected back along a vector that is parallel to but opposite in direction from the wave's source. The device or surface's angle of incidence is...
s for visibility.
Other common changes include the replacement of the stock tires with rain tires or mud and snow tires and the shortening of the vehicle's wheelbase
Wheelbase
In both road and rail vehicles, the wheelbase is the distance between the centers of the front and rear wheels.- Road :In automobiles, the wheelbase is the horizontal distance between the center of the front wheel and the center of the rear wheel...
to improve maneuverability. For smaller applications smaller trucks are used. In Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
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 limit
Road speed limits are used in most countries to regulate the speed of road vehicles. Speed limits may define maximum , minimum or no speed limit and are normally indicated using a traffic sign...
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
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
province of Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
, winter service vehicles use the blue flashing lights associated with emergency service vehicles, rather than the amber or orange used elsewhere. Many agencies also paint their vehicles in high-contrast orange or yellow to allow the vehicles to be seen more clearly in whiteout
Whiteout (weather)
Whiteout is a weather condition in which visibility and contrast are severely reduced by snow or sand. The horizon disappears completely and there are no reference points at all, leaving the individual with a distorted orientation...
conditions.
Some winter service vehicles, especially those designed for use on footpaths or pedestrian zones, 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.
Weather forecasting
Weather forecasting is the application of science and technology to predict the state of the atmosphere for a given location. Human beings have attempted to predict the weather informally for millennia, and formally since the nineteenth century...
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. Most run on wheels, often with snow chains or studded tires, but some are mounted on caterpillar track
Caterpillar track
Continuous tracks or caterpillar tracks are a system of vehicle propulsion in which modular metal plates linked into a continuous band are driven by two or more wheels...
s, with the tracks themselves adapted to throw the snow towards the side of the road. Off-road winter service vehicles mounted on caterpillar tracks are known as snowcat
Snowcat
A snowcat is an enclosed-cab, truck sized, fully tracked vehicle designed to move on snow. Snowcats are often referred to as 'trail groomers' because of their use for grooming ski trails or snowmobile trails...
s. Snowcats are commonly fitted with snowplows or snow groomers, and are used by ski resort
Ski resort
A ski resort is a resort developed for skiing and other winter sports. In Europe a ski resort is a town or village in a ski area - a mountainous area, where there are ski trails and supporting services such as hotels and other accommodation, restaurants, equipment rental and a ski lift system...
s to smooth and maintain piste
Piste
A piste is a marked ski run or path down a mountain for snow skiing, snowboarding, or other mountain sports. The term is European, from the French for trail or track, synonymous with trail, slope, or groomed run in North America....
s and snowmobile
Snowmobile
A snowmobile, also known in some places as a snowmachine, or sled,is a land vehicle for winter travel on snow. Designed to be operated on snow and ice, they require no road or trail. Design variations enable some machines to operate in deep snow or forests; most are used on open terrain, including...
runs, although they can also be used as a replacement for chairlift
Chairlift
An elevated passenger ropeway, or chairlift, is a type of aerial lift, which consists of a continuously circulating steel cable loop strung between two end terminals and usually over intermediate towers, carrying a series of chairs...
s.
Military
Military
A military is an organization authorized by its greater society to use lethal force, usually including use of weapons, in defending its country by combating actual or perceived threats. The military may have additional functions of use to its greater society, such as advancing a political agenda e.g...
winter service vehicles are heavily armoured to allow for their use in combat zones, especially in Arctic
Arctic warfare
Arctic warfare or winter warfare is a term used to describe armed conflict that takes place in an exceptionally cold weather, usually in snowy and icy terrain, sometimes on ice-covered bodies of water...
and mountain warfare
Mountain warfare
Mountain warfare refers to warfare in the mountains or similarly rough terrain. This type of warfare is also called Alpine warfare, named after the Alps mountains...
, and often based on combat bulldozers or Humvees. Military winter service vehicles have been used by the United Nations
United Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...
, Kosovo Force, and the U.S. Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
in Central Europe
Central Europe
Central Europe or alternatively Middle Europe is a region of the European continent lying between the variously defined areas of Eastern and Western Europe...
during the Kosovo War
Kosovo War
The term Kosovo War or Kosovo conflict was two sequential, and at times parallel, armed conflicts in Kosovo province, then part of FR Yugoslav Republic of Serbia; from early 1998 to 1999, there was an armed conflict initiated by the ethnic Albanian "Kosovo Liberation Army" , who sought independence...
, while during the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
, the Royal Marines
Royal Marines
The Corps of Her Majesty's Royal Marines, commonly just referred to as the Royal Marines , are the marine corps and amphibious infantry of the United Kingdom and, along with the Royal Navy and Royal Fleet Auxiliary, form the Naval Service...
and Royal Corps of Signals
Royal Corps of Signals
The Royal Corps of Signals is one of the combat support arms of the British Army...
deployed a number of tracked vehicles in Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
to patrol the NATO border with the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
.
Operation
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....
s. Public works
Public works
Public works are a broad category of projects, financed and constructed by the government, for recreational, employment, and health and safety uses in the greater community...
in areas which regularly receive snowfall usually maintain a fleet of their own vehicles or pay retainer
Retainer
Retainer may refer to:* Retainer , a person, especially a soldier, in the service of a lord in the late Middle Ages** Retainer sacrifice, the sacrifice of a human servant* Retainer...
s 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
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
are the only road-going vehicles entitled to use red diesel. 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
Class A truck
A Class A truck is any combination of vehicles with a GVWR of 26,001 lbs or more pounds, provided the GVWR of the vehicle being towed is in excess of 10,000 pounds . This is also known as a tractor trailer...
or Class B
Class B truck
Any single vehicle with a GVWR of 26,001 or more pounds , or any such vehicle towing a vehicle not in excess of 10,000 pounds GVWR.A Class B commercial driver's license is needed to operate a Class B truck in the United States.-References:...
commercial driver's license
Commercial driver's license
A Commercial Driver's License is a driver's license required in the United States to operate any type of vehicle which has a gross vehicle weight rating of 26,001 lb or more for commercial use, or transports quantities of hazardous materials that require warning placards under Department of...
. Although some agencies in some areas, such as the U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
of Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
, 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 simulator
Driving simulators are used for entertainment as well as in training of driver's education courses taught in educational institutions and private businesses...
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 qualification and a supplemental Winter Maintenance Licence.
Winter service vehicle drivers usually work part time
Part time
A part-time job is a form of employment that carries fewer hours per week than a full-time job. Workers are considered to be part time if they commonly work fewer than 30 or 35 hours per week...
, 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
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 buildings housing computer and closed-circuit...
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
Frost is the solid deposition of water vapor from saturated air. It is formed when solid surfaces are cooled to below the dew point of the adjacent air as well as below the freezing point of water. Frost crystals' size differ depending on time and water vapour available. Frost is also usually...
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 (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...
systems to provide enough power to make the climb. Furthermore, because the tight hairpin turn
Hairpin turn
A hairpin turn , named for its resemblance to a hairpin/bobby pin, is a bend in a road with a very acute inner angle, making it necessary for an oncoming vehicle to turn almost 180° to continue on the road. Such turns in ramps and trails may be called switchbacks in American English, by analogy...
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.
De-icer
De-icers spray heated de-icing fluid, often propylene glycolPropylene glycol
Propylene glycol, also called 1,2-propanediol or propane-1,2-diol, is an organic compound with formula C3H8O2 or HO-CH2-CHOH-CH3...
or ethylene glycol
Ethylene glycol
Ethylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...
, 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 (force)
A fluid flowing past the surface of a body exerts a surface force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the surface force parallel to the flow direction...
they provide while increasing drag
Drag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...
. The ice also increases the weight of the aircraft and can affect its balance.
Cherry picker
A cherry picker , is a type of aerial work platform that consists of a platform or bucket at the end of a hydraulic lifting system.- Design :...
crane, allowing the operator to spray the entire aircraft in as little time as possible; an entire Boeing 737
Boeing 737
The Boeing 737 is a short- to medium-range, twin-engine narrow-body jet airliner. Originally developed as a shorter, lower-cost twin-engine airliner derived from Boeing's 707 and 727, the 737 has developed into a family of nine passenger models with a capacity of 85 to 215 passengers...
can be treated in under 10 minutes by a single de-icing vehicle.
Some road contractors also choose to use de-icers as an alternative to gritters; the vehicle carries a tank of brine
Brine
Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them...
, which is sprayed on the road surface. 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 loadersLoader (equipment)
A loader is a heavy equipment machine often used in construction, primarily used to load material into or onto another type of machinery .-Heavy equipment front loaders:A loader A loader is a heavy equipment machine often used in construction, primarily used to load material (such as asphalt,...
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.
In Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
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, a mixture of sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
and rock salt
Halite
Halite , commonly known as rock salt, is the mineral form of sodium chloride . Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on the amount and type of impurities...
, 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
Impeller
An impeller is a rotor inside a tube or conduit used to increase the pressure and flow of a fluid.- Impellers in pumps :...
, attached by a hydraulic drive system
Hydraulic drive system
A hydraulic drive system is a drive or transmission system that uses pressurized hydraulic fluid to drive hydraulic machinery. The term hydrostatic refers to the transfer of energy from flow and pressure, not from the kinetic energy of the flow....
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
Truck
A truck or lorry is a motor vehicle designed to transport cargo. Trucks vary greatly in size, power, and configuration, with the smallest being mechanically similar to an automobile...
, and some older spreading mechanisms still require grit be manually loaded into the impeller from the hopper.
Freezing-point depression
Freezing-point depression describes the phenomenon in which the freezing point of a liquid is depressed when another compound is added, meaning that a solution has a lower freezing point than a pure solvent. This happens whenever a non-volatile solute is added to a pure solvent, such as water...
, causing it to melt at lower temperatures and run off to the edge of the road, while sand increases traction by increasing friction
Friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and/or material elements sliding against each other. There are several types of friction:...
between car tire
Tire
A tire or tyre is a ring-shaped covering that fits around a wheel rim to protect it and enable better vehicle performance by providing a flexible cushion that absorbs shock while keeping the wheel in close contact with the ground...
s and roadways. The amount of salt dropped varies with the condition of the road; to prevent the formation of light ice, approximately 10 gram
Gram
The gram is a metric system unit of mass....
s per square metre
Square metre
The square metre or square meter is the SI derived unit of area, with symbol m2 . It is defined as the area of a square whose sides measure exactly one metre...
(2 lb/1000 ft²) is dropped, while thick snow can require up to 40 g/m² (8 lb/1000 ft²) of salt, independent of the volume of sand dropped. The grit is sometimes mixed with molasses
Molasses
Molasses is a viscous by-product of the processing of sugar cane, grapes or sugar beets into sugar. The word molasses comes from the Portuguese word melaço, which ultimately comes from mel, the Latin word for "honey". The quality of molasses depends on the maturity of the sugar cane or sugar beet,...
to help adhesion to the road surface. However, the sweet molasses often attracts livestock, who lick the road. The grit is sometimes heated as it is passed out of the nozzle; this helps melt the ice and improves the solubility
Solubility
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
of the salt. Quieter rural roads may be considered too minor to grit, so grit bin
Grit bin
A grit bin or salt bin is an item of street furniture, commonly found in countries where freezing temperatures and snowfall occur, which holds a mixture of salt and grit which is spread over roads if they have snow or ice on them...
s are often provided, containing a mixture of sand and salt for drivers and pedestrians to shovel onto the road themselves. Different types of grit substrate can cause problems for some gritting machines with 'blocking' where sand/grit or salt is damp and clumps together, in these cases an auger
Auger
An auger is a drilling device, or drill bit, that usually includes a rotating helical screw blade called a "flighting" to act as a screw conveyor to remove the drilled out material...
or some form of vibrator has to be employed to enable continuous flow of substrate.
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
Airframe
The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage and exclude the propulsion system...
of aircraft and interferes with the sensitive navigation equipment. As a result, airport gritters spread less dangerous potassium acetate
Potassium acetate
Potassium acetate is the potassium salt of acetic acid.-Preparation:It can be prepared by reacting a potassium-containing base such as potassium hydroxide or potassium carbonate with acetic acid:...
or urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....
onto the runways instead, as these do not corrode the aircraft or the airside equipment.
Materials
Street sweeper
A street sweeper or street cleaner can refer to a person's occupation or a machine that cleans streets, usually in an urban area.-History of street sweeping in the United States:...
and mixed with new salt crystals to be reused in later batches of grit. As a result, operators must regularly purchase large quantities of rock salt.
In some areas of the world, including Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
, dropping salt is prohibited altogether, except on the highest-risk roads; plain sand, without any melting agents, is spread instead. Although this protects the environment, it is more labour-intensive, as more gritting runs are needed; and as the sand is insoluble, it tends to accumulate at the sides of the road, making it more difficult for bus
Bus
A bus is a road vehicle designed to carry passengers. Buses can have a capacity as high as 300 passengers. The most common type of bus is the single-decker bus, with larger loads carried by double-decker buses and articulated buses, and smaller loads carried by midibuses and minibuses; coaches are...
es to pull in at bus stop
Bus stop
A bus stop is a designated place where buses stop for passengers to board or leave a bus. These are normally positioned on the highway and are distinct from off-highway facilities such as bus stations. The construction of bus stops tends to reflect the level of usage...
s. Other areas use alternative chemicals which are less harmful to the environment and cause less corrosion damage to metallic structures. The U.S. state of Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
uses magnesium chloride
Magnesium chloride
Magnesium chloride is the name for the chemical compounds with the formulas MgCl2 and its various hydrates MgCl2x. These salts are typical ionic halides, being highly soluble in water. The hydrated magnesium chloride can be extracted from brine or sea water...
, a relatively cheap chemical similar in molecular structure
Molecular structure
The molecular structure of a substance is described by the combination of nuclei and electrons that comprise its constitute molecules. This includes the molecular geometry , the electronic properties of the...
to sodium chloride, but less reactive, while New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
uses calcium magnesium acetate
Calcium Magnesium Acetate
Calcium magnesium acetate is a deicer and can be used as an alternative to road salt. It is approximately as corrosive as normal tap water, and in varying concentrations can be effective in stopping road ice from forming down to around...
, which avoids the environmentally harmful chloride
Chloride
The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
altogether. Urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....
is sometimes used to grit suspension bridge
Suspension bridge
A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. Outside Tibet and Bhutan, where the first examples of this type of bridge were built in the 15th century, this type of bridge dates from the early 19th century...
s, as it does not react with iron or steel at all, but urea is less effective than salt, and can cost up to 7 times weight-for-weight.
Most grit is mixed with hydrous
Hydrate
Hydrate is a term used in inorganic chemistry and organic chemistry to indicate that a substance contains water. The chemical state of the water varies widely between hydrates, some of which were so labeled before their chemical structure was understood....
sodium ferrocyanide
Sodium ferrocyanide
Sodium ferrocyanide is the sodium salt of the coordination compound of formula [Fe6]4-. It is a yellow crystalline solid that is soluble in water and insoluble in alcohol. Despite the presence of the cyanide ligands, sodium ferrocyanide is not especially toxic because the cyanides are tightly...
which, while harmless in its natural form, can undergo photodissociation
Photodissociation
Photodissociation, photolysis, or photodecomposition is a chemical reaction in which a chemical compound is broken down by photons. It is defined as the interaction of one or more photons with one target molecule....
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 run-off entering fisheries
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
or farm
Farm
A farm is an area of land, or, for aquaculture, lake, river or sea, including various structures, devoted primarily to the practice of producing and managing food , fibres and, increasingly, fuel. It is the basic production facility in food production. Farms may be owned and operated by a single...
s. Gritting vehicles are also dangerous to overtake
Overtaking
Overtaking or passing is the act of one vehicle going past another slower moving vehicle, travelling in the same direction, on a road. The lane used for overtaking another vehicle is almost always a lane further from the road shoulder — that is, to the left in places that drive on the right,...
; 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 motorcycle
Motorcycle
A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...
s, which can lead to skidding, especially around corners.
Gritters can also be used in hot weather, when temperatures are high enough to melt the bitumen used in asphalt
Asphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...
. 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
Aggregate (composite)
Aggregate is the component of a composite material that resists compressive stress and provides bulk to the composite material. For efficient filling, aggregate should be much smaller than the finished item, but have a wide variety of sizes...
from the road surface.
Snow blower
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s 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
Windrow
A windrow is a row of cut hay or small grain crop. It is allowed to dry before being baled, combined, or rolled. For hay, the windrow is often formed by a hay rake, which rakes hay that has been cut by a mower machine or by scythe into a row, or it may naturally form as the hay is mowed...
from blocking driveways.
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 rollerRoller (agricultural tool)
The roller is an agricultural tool used for flattening land or breaking up large clumps of soil, especially after ploughing. Typically, rollers are pulled by tractors or, prior to mechanisation, a team of animals such as horses or oxen....
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
Ski resort
A ski resort is a resort developed for skiing and other winter sports. In Europe a ski resort is a town or village in a ski area - a mountainous area, where there are ski trails and supporting services such as hotels and other accommodation, restaurants, equipment rental and a ski lift system...
s, where they are used to maintain smooth, safe trails for various wintersports, including skiing
Skiing
Skiing is a recreational activity using skis as equipment for traveling over snow. Skis are used in conjunction with boots that connect to the ski with use of a binding....
, snowboarding
Snowboarding
Snowboarding is a sport that involves descending a slope that is covered with snow on a snowboard attached to a rider's feet using a special boot set onto mounted binding. The development of snowboarding was inspired by skateboarding, sledding, surfing and skiing. It was developed in the U.S.A...
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
Snowcat
A snowcat is an enclosed-cab, truck sized, fully tracked vehicle designed to move on snow. Snowcats are often referred to as 'trail groomers' because of their use for grooming ski trails or snowmobile trails...
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-pipe
Half-pipe
A half-pipe is a structure used in gravity extreme sports such as snowboarding, skateboarding, skiing, freestyle BMX, and inline skating. The structure is wood, concrete, metal, earth, or snow. It resembles a cross section of a swimming pool, essentially two concave ramps , topped by copings and...
s and ramps
Mini ramp
A mini ramp is a type of half-pipe which is typically less than high. Any ramp smaller than this that is not a vert ramp & is commonly called a mini ramp. Mini ramps can be as small as in height. While many ramps this size are designed to be forgiving to beginners, some are built more...
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. Grooming removes nutrients and minerals from the soil underneath the snow and the regular pressure from the grooming vehicle increases the infiltration
Infiltration (hydrology)
Infiltration is the process by which water on the ground surface enters the soil. Infiltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall or irrigation. It is measured in inches per hour or millimeters per hour. The rate decreases as the soil becomes...
rate of the soil while decreasing the field capacity
Field capacity
Field capacity is the amount of soil moisture or water content held in soil after excess water has drained away and the rate of downward movement has materially decreased, which usually takes place within 2–3 days after a rain or irrigation in pervious soils of uniform structure and texture...
. This increases the rate at which water can soak through the soil, making it more prone to erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
.
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 smaller tank full of boiling water, heated by a powerful burner. The gases from the burner are bubbled through the water, causing some of the water to spill over into the melting pit, melting the snow instantly. The meltwater is discharged into the storm drainStorm drain
A storm drain, storm sewer , stormwater drain or drainage well system or simply a drain or drain system is designed to drain excess rain and ground water from paved streets, parking lots, sidewalks, and roofs. Storm drains vary in design from small residential dry wells to large municipal systems...
s.
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
s (59 ft), with the largest being hauled by semi-trailer
Semi-trailer truck
A semi-trailer truck, also known as a semi, tractor-trailer, or articulated truck or articulated lorry, is an articulated vehicle consisting of a towing engine , and a semi-trailer A semi-trailer truck, also known as a semi, tractor-trailer, or (in the United Kingdom and Ireland) articulated truck...
tractor unit
Tractor unit
A tractor unit, prime mover , road tractor, or traction unit is a heavy-duty commercial vehicle within the large goods vehicle category, usually with a large displacement diesel engine, and several axles. The tractor unit serves as a method of moving trailers...
s. 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 tons of snow per hour, compared to the 5000 tons per hour capacity of any large snow blower. However, 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, as the snow is melted on board, the costs of removing the collected snow from the site is removed. 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 hydraulicallyHydraulics
Hydraulics is a topic in applied science and engineering dealing with the mechanical properties of liquids. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on the engineering uses of fluid properties. In fluid power, hydraulics is used for the generation, control,...
-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
Highways Agency
The Highways Agency is an executive agency, part of the Department for Transport in England. It has responsibility for managing the core road network in England...
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.
Grader
A grader, also commonly referred to as a road grader, a blade, a maintainer, or a motor grader, is a construction machine with a long blade used to create a flat surface. Typical models have three axles, with the engine and cab situated above the rear axles at one end of the vehicle and a third...
s, bulldozer
Bulldozer
A bulldozer is a crawler equipped with a substantial metal plate used to push large quantities of soil, sand, rubble, etc., during construction work and typically equipped at the rear with a claw-like device to loosen densely-compacted materials.Bulldozers can be found on a wide range of sites,...
s, skid loader
Skid loader
A skid loader or skid steer loader is a small rigid frame, engine-powered machine with lift arms used to attach a wide variety of labor-saving tools or attachments. Though sometimes they are equipped with tracks, skid-steer loaders are typically four-wheel drive vehicles with the left-side drive...
s, 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 overtake
Overtaking
Overtaking or passing is the act of one vehicle going past another slower moving vehicle, travelling in the same direction, on a road. The lane used for overtaking another vehicle is almost always a lane further from the road shoulder — that is, to the left in places that drive on the right,...
; 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
Traffic light
Traffic lights, which may also be known as stoplights, traffic lamps, traffic signals, signal lights, robots or semaphore, are signalling devices positioned at road intersections, pedestrian crossings and other locations to control competing flows of traffic...
s and tram stop
Tram stop
A tram stop is a place designated for a tram to stop so passengers can board or alight it. Tram stops share most characteristics of bus stops, but because trams operate on rails, they often include railway platforms, especially if stepless entries are provided for accessibility...
s, 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 10 centimetres (4 in). Snow deeper than this however can clog the brushes, and most snow sweepers cannot be used to clear snow deeper than 15 centimetres (6 in). 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
Road slipperiness
Road slipperiness or skid resistance is the technical term for the cumulative effects of snow, ice, water, loose material and the road surface on the traction produced by the wheels of a vehicle...
. The wheel, allowed to roll freely, is slightly 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
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
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
Compact car
A compact car , or small family car , is a classification of cars which are larger than a supermini but smaller than or equal to a mid-size car...
or estate cars or to a small trailer
Trailer (vehicle)
A trailer is generally an unpowered vehicle pulled by a powered vehicle. Commonly, the term trailer refers to such vehicles used for transport of goods and materials....
, rather than the large trucks used for other winter service equipment, as the surface friction tester works best when attached to a lightweight vehicle.
External links
General- Snow removal site links—National Snow and Ice Data CenterNational Snow and Ice Data CenterThe National Snow and Ice Data Center, or NSIDC, is a United States information and referral center in support of polar and cryospheric research...
- Road Salt Management Best Practices-Transportation Association of Canada Resource Centre
Road snow removal
- Master Plan for Snow and Ice Control—City of Sapporo
- Driving in adverse weather conditions—The Highway CodeHighway CodeThe Highway Code is the official road user guide for Great Britain. In Northern Ireland the applies while the Republic of Ireland has its own Rules of the Road. It contains 306 numbered rules and 9 annexes covering pedestrians, animals, cyclists, motorcyclists and drivers...
- Winter Service—The Highways AgencyHighways AgencyThe Highways Agency is an executive agency, part of the Department for Transport in England. It has responsibility for managing the core road network in England...
- Snow Removal and Snow Driving—Virginia Department of TransportationVirginia Department of TransportationThe Virginia Department of Transportation is the agency of state government responsible for transportation in the state of Virginia in the United States. Headquartered in Downtown Richmond, VDOT is responsible for building, maintaining, and operating the roads, bridges and tunnels in the...
- Photograph: Road rolling-about 1885-under direction of James Little, overseer of highways, Calumet Township, Michigan, USA-The Bentley Historical LibraryBentley Historical LibraryThe Bentley Historical Library is a historical library located on the University of Michigan's North Campus in Ann Arbor. It was established in 1935 by the regents of the University of Michigan...
Airport snow removal
- Winter services at Dresden Airport—Dresden Airport
- Snow & Ice Control Procedures—St. Louis Downtown AirportSt. Louis Downtown AirportSt. Louis Downtown Airport is a public-use airport located in the St. Louis Metropolitan Area, one mile east of the central business district of Cahokia, in St. Clair County, Illinois, United States. It is owned by the Bi-State Development Agency. The airport is located less than 3 miles from...
- Snow clearance at Vnukovo International Airport—Vnukovo International AirportVnukovo International AirportVnukovo International Airport , is a dual runway international airport located southwest from the centre of Moscow, Russia. It is one of three major airports serving Moscow...