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Towing is the process of coupling one object to anothers, so that one can be pulled along behind the other. The towing source (lead object) is usually a truck or other motorized land vehicle, but anything from waterborne vessels to tractors to animals to people can tow cargo. The coupling may consist of a chain, rope, bar, integrated platform, or some other means of keeping the two objects together while in motion.
A common use of the term is for moving a disabled or seized vehicle via a tow truck or "wrecker." However, any kind of secondary object, including cargo carriers hooked in a tractor-trailer combination, or carriers (trailers) hooked to small- or medium-duty vehicles via trailer-hitch, may be said to be an instance of towing. Many countries or industries have standards for carriers, lighting, and coupling for trucks and cars, to ensure safety and interoperability of towing equipment.
Troop carrying and cargo carrying gliders were towed behind powered aircraft during WWII and remains a popular means for modern leisure gliders to take off. In the maritime industry in particular, towing is a refined science.
This section refers to the towing of a cargo-carrying device behind a truck or car.
Most trailers fit into one of three categories:
There are many safety considerations to properly towing a caravan or trailer / travel trailer starting with vehicle towing capacity and ranging through equalizer hitches to properly and legally connecting the safety chains.
According to the United States National Highway Traffic Safety Association, more than 65,000 crashes involving passenger vehicles towing trailers occurred in 2004 in the US, jumping nearly 20 percent from the previous year.
In 2006, Master Lock did their annual study on towing safety to see how many Americans tow their cargo correctly. The study, Towing Troubles included responses from trailer owners across the country and found that while the majority of trailer owners believe they know what they’re doing when it comes to towing, most were lacking the proper education. Master Lock reported that 70 percent of trailer owners did not fully know the correct way to tow their cargo.
An important factor in towing safety is tongue weight, the weight with which the trailer presses down on the tow vehicle's hitch. Insufficient tongue weight can cause the trailer to sway back and forth when towed. Too much tongue weight can cause problems with the tow vehicle.
Of the many cars fitted with towbars, most are likely to have fitted towing electrics which are ‘hidden’ from the car. This electrical installation is commonly called ‘By-pass electrics’. This system is used to protect the car's lighting systems from potential damage if wiring in a trailer should malfunction. It is a tried and tested system in very wide use. Bypass systems are found both in "universal" (non-vehicle-specific) systems and in dedicated and OEM systems.
Since the early 2000s, vehicle technology has moved forward introducing CANbus network systems which allowed the interaction of different systems, and also the detection of a trailer or caravan. In some cases, the manufacturers have not only designed automobiles to sense the presence of a trailer, but they have also created enhanced new features within the systems connected to the network. This actually makes it important that these particular vehicles can "see" the trailer or caravan. A few of these new features are for safety and stability, but most are merely convenience things like automatically switching off the rear fog light and parking sensors. The main new safety feature, appearing now on some cars, is the Trailer Stability Program which automatically turns on when a trailer detected in the network through the dedicated sensors.
Some of the advanced systems being introduced in certain vehicles, that may make use of detecting the presence of a trailer are: lane change assistant, brake electronics, adaptive cruise control, suspension system (ASS), engine electronics, engine cooling system, parking aids, and reversing camera.
TSP or Trailer Stability Program is one feature which has been added to some vehicles, to help correct the ‘snaking’ action of a trailer. With such advanced technology, some braking systems have even evolved further by being operated electronically, without the need for hydraulics. Braking can become more controlled with faster braking efficiency when towing. Some suspension systems can now detect a trailer and allow for a more level towing adjustment when the load is applied on the towing hitch. ACC (Adaptive Cruise Control) systems are meant to ‘detect’ a trailer in order to create a greater braking distance between vehicles. It might be considered unwise to bypass such vehicles' trailer detection systems as these vehicles may be designed to behave in a different way when a trailer is attached.
Some manufacturers either put a prepared connector in the vehicle which is a preparation on the network (Ford, Volvo) to accept a specially designed towing module, or have designed the trailer to be ‘detected’ through connections directly onto the databus (VAG, BMW). With such connections the vehicle will know when a trailer plug is connected to the socket.
On vehicles that do not have safety features that depend on the vehicle sensing the presence of a trailer, bypass systems, properly installed by expert fitters, are very efficient and cost effective alternatives to expensive OEM and other dedicated kits. All bypass kits will be type approved for use on vehicles (check for the (e) mark). They have the built-in advantage of completely isolating the trailer from the vehicle's lighting system, thus protecting against damage to the car caused by any failure within the trailer's wiring. However, a number of manufacturers do not recommend connections to be made on the lighting harnesses.
This system is used to protect the car's lighting systems from potential damage if wiring in a trailer should malfunction. It is a tried and tested system in very wide use. Bypass systems are found both in "universal" (non vehicle-dedicated) systems and in dedicated and OEM systems. It works by taking a small current signal from the vehicle's lighting harness to trigger a relay and send a direct power supply to the towing socket. It does not communicate with the vehicle and will not activate any safety or convenience systems. It has the built-in advantage of isolating the trailer wiring from that of the towing vehicle and thus preventing overloading the vehicle's own lighting harness which may be minimal gauge cabling. The connection onto this harness will cause damage if solder or crimp connectors are used! However, by-pass systems should protect the car's electrical modules from damage should the wiring in a towed trailer malfunction. It is not advised for use in cars that depend on sensing the presence of a trailer to activate towing-related safety features within the car.(See Trailer Stability Programme). In addition to this, there are a number of vehicle manufacturers that do not recommend or actually ban any connections to be made from the vehicle lighting harness.
12N is the designation for the older 7-pin lighting socket conforming to ISO 1724, used when towing just a trailer or caravan (without the need for charge or fridge functions). In the UK it has all the functions of the rear lights on a vehicle except for reverse. These sockets are not waterproof and suffer from "pin burn-out" when worn.
12S is an additional 7-pin socket conforming to ISO 3732, mainly used when towing caravans. It consists of a permanent 12v power supply, and usually a switched 12v power supply for the fridge (UK). It also contains a feed for the reverse lights on the caravan.
ISO 11446 is the new 13-pin standard socket being fitted for all new U.K. caravans and trailers sold from 2009 onwards. It can be wired with the same functions as both the 12N and 12S sockets, or with just the lighting functions including reverse (required on all trailers and caravans from October 2012). The socket has been designed to be waterproof, easy to fit/remove (twist operation), the same size as one 12N socket (ideal for detachable towbars as unobtrusive), and with good fitting quality terminals that avoid any pin burnout or voltage failure.
Another advance in trailer safety is the development of the Trailer Stability Program, built into some Electronic Stability Control systems in today's motor vehicles. These systems can detect the "snaking" of a trailer or caravan and counteract it by braking individual wheels, reducing engine torque and slowing the vehicle down. It is important to note that activation of TSP normally requires a vehicle-specific wiring loom to be installed.
Towing capacity is a measure describing the upper limit to the weight of a trailer a vehicle can tow and may be expressed in pounds or kilograms. Some countries require that signs indicating the maximum trailer weight (and in some cases, length) be posted on trucks and buses close to the coupling device.
For cars and light trucks, towing is accomplished via a trailer hitch. In addition to the vehicle limits, the hitch assembly may have its own set of limits, including tongue weight (the amount of weight that presses downward on the hitch) and trailer weight (the full weight of the trailer, including contents). When the hitch is a factory option, the hitch capacity is usually stated in the vehicle documentation as a towing speciifcation, and not otherwise marked on the vehicle.
Towing capacity may either refer to braked or unbraked towing capacity.
Braked towing capacity is the towing capacity of a vehicle if the trailer being towed has its own braking system, typically connected to the vehicle's braking system via the trailer cable. Braked towing capacity is typically significantly greater than unbraked towing capacity.
Unbraked towing capacity is the towing capacity of a vehicle towing a trailer that does not have its own braking system.
A tow hitch, tow bar or recovery point is a device attached to the chassis of a vehicle for towing.
It can take the form of a tow-ball to allow swivelling and articulation of a trailer, or a tow pin and jaw with a trailer loop - often used for large or agricultural vehicles where slack in the pivot pin allows the same movements. A further category is the towing pintle used for military vehicles around the world with a hook and locking catch.
In the case of towing hitches designed to carry other vehicles, there are more specialized types, described immediately below.
Towing of cars and trucks is a unique form, with an industry dedicated to it. Specialized "tow truck" vehicle types are most often used. Some of these are flatbed, with hydraulic tilting beds and winches and dollies to position the car behind the bed and pull it up onto the bed. Others have a specialized boom hitch instead of a flatbed, which will lift one end of the car and allow it to ride on its remaining tires; they otherwise have similar equipment to the flatbeds and position and perform much like them. In other cases, a specialized vehicle dolly can be attached to a standard vehicle hitch; for example, some moving vehicle rental companies, such as U-Haul, will rent these dollies for one-way transport of cars.
Hitch tow trucks are mostly sized for cars and light duty trucks. Larger versions, with a long, weighted body and heavier duty engines, transmissions, and tow hooks, may be used for towing of disabled buses, truck tractors, or large trucks. The artificial sizing and weighting must be designed to withstand the greater weight of the towed vehicle, which might otherwise tip the tow truck back.
When many cars are to be transported, rather than using a specialized vehicle, a specialized trailer may be used instead, attached to a standard tractor truck or other large vehicle. These "motor carriers" often bring cars from factories to dealers. They typically have two levels that each hold 3-5 cars, ramps for moving the cars from ground to either level, and hook/chain ties and mounts to secure the cars for transport. Their beds, on each level, may have channels or tracks to guide loading and further maintain transport stability.
Vehicle towing may be performed for the following reasons:
This section refers specifically to the laws of various countries regarding the towing of a car or truck by a specialty wrecker or tow truck.
The towing industry is known to have substantial potential for abuse, as towing most often occurs in difficult situations, without many options for the consumer to turn to. IN addition, in certain situations, towing operators may initiate a towing procedure that is unwarranted, and the consumer may be forced to make a payment to the operator before the vehicle is released. Various consumer citizen protection laws have been enacted by many jurisdictions to protect the consumer for predatory towing or predatory towing charges.
Other laws may govern training and licensing of tow truck operators and businesses, safety equipment, safe practices, and special permits for operating on certain roadways or in certain areas.
In the United States, several states have laws that regulate the circumstances under which a car may be towed. Some of these laws are designed to prevent "predatory towing" whereby a legally parked vehicle is towed — or an illegally parked vehicle is towed by a towing operator unaffiliated with the parking facility (private or public) — in order to charge high fees from the owner. Even when the predatory tow is stopped, if the vehicle is already hooked up to the tow truck in any fashion, the car is essentially disabled until the operator releases it, and the operator can therefore extort money from the consumer.
Even where towing is performed legally, and even with the consumer's request for a tow, the towing company gains physical possession of the vehicle. The towing fees may be unexpectedly high in the absence of regulation.
In some jurisdictions, kidnapping laws may ban the towing of occupied vehicles.
California law requires the tow company to immediately and unconditionally release a vehicle if the driver arrives prior to it being towed from the private property and in transit. The intent was to avoid the likelihood of dangerous and violent confrontation and physical injury to vehicle owners and towing operators, the stranding of vehicle owners and their passengers at a dangerous time and location, and impeding expedited vehicle recovery, without wasting law enforcement’s limited resources.
Some limited access highways, especially the Garden State Parkway and the New Jersey Turnpike, require specially designated towing businesses to be the only tow operators on them. This is to allow for better traffic flow and safety, as not all tow operators are familiar with the roads, access points and turnaround points, road construction quirks, and methods to quickly and safely remove disabled cars from the roadway. There is also the concern of arrival delay; the roadway authorities wish to avoid out of area tow companies, as the delay for arriving from far away increases the length of traffic delays in time and distance.
Oregon law requires that the tower release a vehicle at no charge only if the driver is present prior to the hookup being complete. The tower must also take at least one photograph of the vehicle and record the time and date of the photograph. The photograph must show the vehicle violation taking place.
Virginia and its municipalities have enacted anti-"predatory towing" legislation. Some features of the legislation include the requirement to post warning signs at all entrances, setting maximum fees for towing and storage, and requiring photographs to be taken before towing to show the condition of the vehicle as well as the lawfulness of the towing.
All Australian States have laws which regulate the towing industry, particularly that part of the industry engaged in towing light and heavy vehicles involved in road accidents.
The Accident Towing Services Act is the prime towing industry statute in the State of Victoria. The scheme sets economic, occupational and general consumer protection controls over the accident towing industry. First, the statute restricts the number of accident towing vehicles across the State and also contains a scheme regulating the orderly allocation of tow trucks to road accident sites. Second, the Act sets mimimum standards on the character of industry participants and also regulates the behaviour of participants once they enter the industry.
The framework of offences in the Act broadly seeks to give practical effect to the "chain of responsibility" concept in the accident towing sector. The concept seeks to identify the industry parties who are in a sufficient position of control over risks, in this case potentially unsafe and unethical conduct following road accidents, and to allocate responsibility through law accordingly in order to deter and punish those behaviours.
The behavioural controls in the Act cover a wide range of activities and practices including the allocation of tow trucks to accident sites in "controlled areas" and conduct at road accident sites and during post accident repair work. The scheme was broadly prompted by consumer protection sentiment, in particular, the recognition of the vulnerability of road accident victims. Care was evident during development of the scheme to maintain and enhance existing character standards in the sector due to past behavioural issues in Victoria including the infiltration of criminal elements into some areas and conflict at accident scenes.
As of the 1st of August 1998 all Passenger Carrying Vehicles up to 3500 kg Gross Vehicle Weight (M1 Vehicles) can only be fitted with European Type Approved towbars if the vehicle has received European Whole Vehicle Type Approval. Non M1 vehicles, Light Commercial Vehicles and private imports from outside the EEC are not required to use Approved Towbars.