What is an Off Highway Vehicle?
An off highway vehicle (OHV) is a vehicle used on steep or uneven ground and covers vehicles that may be used in construction or agriculture. OHVs are designed for off-road use, and may be enclosed or open air.
Off highway vehicles include quad bikes, dirt bikes, dune buggies and there are many types of all terrain vehicles (ATVs) included, but their intended purpose can be very different than a motor vehicle built for industrial and agricultural purposes.
The typical “off highway vehicle”, is characterized by its large tires with deep treads, flexible suspension and may occasionally have caterpillar tracks. This includes tractors, forklifts, cranes, combine harvesters, bulldozers, etc.
What does Off Highway Use Mean?
Off highway use simply means using a vehicle in the off-road environment. While many off highway vehicles are designed to travel on roads, such as ATVs with proper license plates, other off highway vehicles are used, for the most part off road, away from public roadways and lands as how they are used in OHV recreation.
For the purposes of this FAQ we will draw the line surrounding construction and agricultural vehicles and ATVs – separated and taken differently.
What is the Difference between OHVs and ATVs?
OHV generally means a 4X4 type off highway vehicle, made with automotive manufacturing means. ATV generally means a smaller type of off road motorcycle manufactured or designed by motorcycle manufacturers.
While most OHVs used in agriculture and construction (‘heavy machines’) are not that, there are many types of OHV which are not industrial, including:
All Terrain Vehicles (ATV)
The types of vehicles that are all-terrain vehicles (ATV) include three or four wheeled bikes which use a low pressure tire. These OHVs are not always street legal where they are being used, such as some states in Australia, Canada and the United States.
Both OHV use permits and OHV registration are often used for safe and responsible operation of these types of vehicle, and a requirement to meet emissions standards, which could be the same as registered road-based vehicles or not.
ATVs typically have a handlebar for steering, have the driver straddle the vehicle for riding on a seat similar to a motorcycle.
Recreational Off Highway Vehicles (ROV)
Other types of OHVs may be recreational. Recreational OHVs have 4 or more wheels, have bucket or bench seats, and use automotive controls for steering throttle and brakes (vs. motorcycle type control and steering).
These types of vehicle may also use roll bars, occupant restraints and also travel over 30 mph. These vehicles are often raced in motorsports.
Utility Task Vehicles (UTV)
Other OHVs that are not used in agriculture or industry are utility vehicles with many of the same abilities as ROVs. UTVs are like ROVs in many ways, and can often be used for things such as user group sight-seeing in areas with difficult to cover ground that typically have low traction.
Since these vehicles have such high off-road clearance and traction, they are well-suited for this job, aside from the fact that most UTVs will not go faster than 30mph.
History of Off Highway Vehicle
The development of large machines for industrial use and development of other types of OHVs grew in parallel, but the work performed with trades today with large agricultural machines, was done by animal power or human power, before the 19th and early 20th centuries.
Those first changes occurred with the invention of steam engines when early varieties of combine harvester and steam tractor first appeared.
The next major change with new machines occurred with the internal combustion engine with kerosene and ethanol engines being replaced by diesel engines. The first mass-produced heavy machine was the Fordson tractor produced in 1917.
On the other hand, in history construction vehicles drew their roots from the first continuous tracked vehicle with the Lombard Steam Log Hauler in 1901. Of course, tracks served as a short term method of use in World War I on tanks and then civilian use on machines like the bulldozer.
Bucket wheel excavators, which have been in an ongoing development since the 1920s as mobile land machines, while smaller electric powered vehicles, cited as forklifts were developed subsequently.
As stated, the development and use of industrial vehicle has developed in parallel with the other forms of OHVs.
Over a decade, between 1906 and 1916, Adolphe Kégresse designed the original Kégresse track, a conversion for the car of the Czar Nicholas II of Russia which employed the flexibile belt on the caterpillar track, rather than interlocking metal segments.
These systems could also be adapted onto a standard truck or car so that it was a half-track capable of travelling on rough or soft ground.
After the 1917 Russian Revolution, Kégresse returned to France, and he applied the system to Citroën automobiles between 1921 and 1937. These were the prototypes of many of today’s off-highway (OHV) and military vehicles.
Thomas Poulter created the first large wheeled vehicle between 1937and 1939 – the Antarctic Snow Cruiser. Although it featured many innovative features, it was discontinued because it would not operate under extreme conditions.
Following World War II, the market for small utility vehicles burgeoned, with Jeep being the most famous.
This contributed to the burgeoning of recreational off-road usage by civilians, and spurred similar vehicles being developed in the UK by Land Rover, and in Japan by Toyota, Datsun/Nissan, Suzuki and Mitsubishi.
These civilian examples were developed from the 1960s onwards through to the present day, with a growing number of luxuries added in the subsequent decades – eventually becoming the basis for the crossover and Sports Utility Vehicles (SUV) of the present day.
Future of Off Highway Vehicle
Similar to regular electric vehicles, now many heavy machinery manufacturers are developing fully or partially electric-powered equipment. Some commercial workable models are already entering the marketplace, while other equipment is still being developed.
Heavy machinery OHV manufacturers are also exploring robotics and autonomy, with a handful of units already available. With the demand for more sustainable solutions and the push for Net Zero, we can be sure the developments will continue to grow in the years to come.
Characteristics of an Off Highway Vehicle
Off highway vehicles can differ greatly in construction, but share certain attributes.
All vehicles want low ground pressure so they do not sink into the soft ground, good ground clearance so they do not bottom out on obstacles and wheels/tracks that maintain contact with the ground so the vehicle can establish traction.
Wheeled vehicles accomplish this by using either large tires or added tires, as well as high and flexible drive suspension. Tracked vehicles maintain ground contact in two ways – by using wider tracks, or if they utilize wheels (as in half-tracks), using flexible suspension on the wheels.
Most off highway vehicles also utilize low gear ratios, meaning keeping a portion of the engine’s horsepower available while travelling slow across difficult terrain.
This can be through a very low first gear (called ‘granny’) or as a result of another gear box in line with the first (called a ‘reduction drive’). Some types of vehicles may also be able to include torque converters to facilitate the gear reduction.
Wheels or Tracks?
The debate really comes down to cost and suitability with tracked drives being more costly to manufacture and maintain than wheels. Wheels will also give a greater top speed but tracks are better in adverse conditions.
Off-road vehicles typically provide power to all of the wheels so as to maintain traction on slippery surfaces.
This means four-wheel drive but these vehicles that are designed to be used both on-road and off-road usually allow for this to be switched to two-wheel drive for an on-road setting.
The majority of heavy equipment will utilize tracks to handle severe service conditions, however many heavy machines will utilize tyres. These specific tyres can be very expensive, and there are several classifications for different uses:
- Off-the-Road Tyres – Transport (for earthmoving machines), work (for slow moving machines) and load and carry (for moving material and digging)
- Off-Highway Tyres – Compactor (C), Earthmover (E), Grader (G), Loader (L), Log-Skidder (LS) and Mining and Logging (ML)
These tyres have different tread styles for hard packed surfaces, soft surfaces and rock.
For recreation use, the tyres are classified in a couple different ways, those for all terrain (AT), those for muddy terrain (MT), but then there are sand blaster and mud bogging tyres which are for extreme off-road environments such as dirt, sand and in some cases, water allowing the driver to maintain traction at steep angles and higher speeds associated with off-road motorsport.
What is the Difference between Green and Yellow Off Highway Vehicles?
Many OHVs, when referring to construction or agricultural use and it has become a convention of referring to these vehicles as green (agricultural) or yellow (construction).
Yellow off highway vehicles are used for earthmoving, and other construction tasks. Green off highway vehicles can be tractors, combine harvesters and many other agricultural vehicles.
This neat colour differentiation comes because many traditional agricultural manufacturers (like John Deere) painted their agricultural equipment green, while many of the construction vehicles manufactured (like JCB) painted their vehicles yellow.
There of course may be other available colours for these vehicles, however these terms established themselves over time.