Trunk (automobile)

An advertisement from 1924 for Moynat's rear-attached trunk, which held two specially designed suitcases. The 1931 Ford Model A features a separate trunk mounted to its rear rack (the open lid forward of it is for the car's rumble seat). Storage area was integrated within the body in later models. The 1967 AMC Marlin features a small trunk lid opening because of its fastback design. A covered spare tire is visible. On many rear-engined cars, such as this Porsche 911, the trunk is in the front. This add-on trunk on a small Smart car is a 21st-century throwback to the early 20th-century add-on trunks. 1970s/80s style Citroën 2CV boot extension used for touring. Traction Avant rears. The boot was lengthened and its volume doubled in Autumn 1952.

The trunk or boot of an automobile or car is the vehicle's main storage compartment. Trunk is used in North American English and Jamaican English, while boot is used elsewhere in the English-speaking world – except in South Asia, where it is usually called a dickie.

The compartment is most often located at the rear of the vehicle, as storage areas are normally at the end of the vehicle opposite to which the engine is located. Some mid-engined cars (such as the Ferrari 360) and rear-engined cars (such as the Volkswagen Beetle and the classic Porsche 911) have it in the front. Vehicles such as the Volkswagen Type 3 have storage compartments both in the front and in the rear, above the low-profile boxer engine. The mid-engined Fiat X1/9 also has two storage compartments, although the rear one is very small, but practically cuboid in shape. Sometimes during the life of the vehicle the lid may be restyled to increase the size or improve the practicality and usefulness of the boot/trunks shape. Examples of this include the Beetle redesign to the 1970s 'Super Beetle' and the pre-war and 1950s post war Citroën Traction Avant.

Etymology

The usage of the word "trunk" comes from that being the word for a large travelling chest, as such trunks were often attached to the back of the vehicle before the development of integrated storage compartments in the 1930s; while the usage of the word "boot" comes from that being the word for a built-in compartment on a horse-drawn coach (originally used as a seat for the coachman and later for storage). The usage of the word "dickie" comes from that being the British word for a rumble seat, as such seats were often used for luggage before cars had integrated storage.

In France, from 1900 onwards, the luggage maker Moynat became the indisputable market leader in automobile luggage, for which the house developed a number of patented products including the rear-attached limousine trunk with custom fitted suitcases. In 1928 came the side or lateral sliding trunk, a mechanism that foreshadowed the development of integrated trunks in vehicles from the 1930s onwards.

Classification

Open or closed compartments

Open compartments are those found in station wagons and SUVs, while closed compartments have a trunk lid and are typically found in saloon (sedan) or coupé bodies. Closed compartments are separated from the passenger compartment by rigid body elements or seats, and are generally trimmed in simple materials, whereas many station wagons are trimmed with better looking materials as the space is an extension of the passenger compartment. In order to hide the compartment content of station wagons or hatchbacks from thieves or sunlight, a cover may be fitted. On hatchbacks this often has the form of a rigid parcel shelf, while station wagons and many SUVs have a roller blind in a removable cassette.

Increased variability

To make the space more flexibility, many cars have foldable rear seats, which can increase the size of the trunk when needed.

Active and passive safety

Active safety by luggage retention

The trunk space can contribute to the active and passive safety of the vehicle. Active safety may be promoted in vehicles that are partially loaded. Here the use of lashing eyes to restrain luggage can prevent or reduce damage to the vehicle and its occupants in severe manoeuvres. In driving while cornering 'in-extremis', the prevention of sudden weight transfer due to poorly loaded luggage can be enough to prevent the vehicle losing grip, and potentially avoiding thereby an accident; active safety.

Passive safety by luggage retention

If a crash should occur, lashing eyes can reduce the severity of outcome of the accident by keeping the luggage in the loadspace compartment and thereby preventing projectiles from harming correctly restrained passengers in the passenger compartment. These lashing features may be in the form of fixed or foldable loops or in the case of certain European vehicles (for example BMW X3, BMW X5, and various VW and Audi models) combine sliding loops in a rail system to allow optimal positioning of the lashing eyes. At the same time this eases the integration of accessories for loadspace management; dividers, bike carriers etc. into the interior of the vehicle, a principle that has been applied in cargo vans and air transport for many years.

Barrier nets/grids

In vehicles with open luggage compartments, some are fitted with metal grids or guards to retain loose items in case of collision, or to simply create a bulkhead between the load in the trunk - for example animals - separated from the otherwise unprotected passenger space. Another solution for items that have not been restrained is the loadspace barrier net. These may be directly attached to the body structure or, in vehicles with loadspace cover cassettes, as a combined loadspace cover and barrier net (ger. Kombirollo), the net confining luggage to the loadspace in case of emergency braking and minor crash impacts. These nets have the advantage over metal guards that they can be rolled-up when not in use, taking up much less space than a comparable guard. A guard may however be tailored for an even tighter fit to the body interior contours than a roll-away net.

Additional functions

Beyond carrying luggage, the trunk/boot of most passenger vehicles commonly contains various other components often behind the trimmed surfaces of the interior. These components may be accessed by the customer or the service personnel through (in some cases lockable) hatches in the trim, or by removing carpet and support boards etc. Typical components:

• Emergency supplies
• Spare tire
• jack and lug wrench
• on-board tool kit for do it yourself repairs
• electronics for sound, video, GPS, etc.
• Battery and hybrid energy store (see plug-in hybrids).
• Fuse boxes
• CNG/LPG tanks (for bivalent engines)
• Additional folding, or 'third-row', seating (increasingly in open loadspaces)

Dangers

Children - and sometimes adults who climb in to work on the vehicle - trapped in trunks can die of suffocation or heat stroke. Once in the trunk, they may not be able to get out, even if they entered through the interior, because many rear seats only release to the trunk from inside the passenger area. Beginning with the 2002 models, a glow-in-the-dark inside trunk release is required on all vehicles with conventional trunks sold in the United States. Hatchbacks, wagons, vans and SUVs are exempt from this requirement because it is assumed a trapped person can kick out any cargo cover to gain access to the main interior and passenger doors.

Shelves and boards

Some vehicles offer configurable cargo conveniences such as a shelf or board. They often serve various purposes. The multiposition rear shelf on the Chrysler PT Cruiser can be used as a table for a picnic, a second cargo layer, or a security screen. The Citroën C3 has a foldable segmented false floorboard that compartmentalises the cargo area, makes loading easier, and evens out the load floor when the back of the rear seat is folded down.

Central locking

The locking of the trunk may be achieved together with the passenger compartment.

Main article: Power door locks

Remote opening

Some cars include a function to remotely open the trunk. This may be achieved through a variety of means

• release of the latch whereby the doorseals push the decklid away from the lock, the trunk is then open, and the lid may not have revealed the opening.
• release of the latch whereby a spring pushes the decklid away from the lock and open, the trunk is then open, and the lid reveals the opening.
• release of the latch and actuation of a drive, whether hydraulic (BMW 7 Series) or electric (BMW X6), which pushes the decklid away from the lock; the trunk is then open, and the lid reveals the opening. This may then be electrically closed again.

See also

• Car boot sale
• Continental tire
• Hood (vehicle)
• Refrigeration compartment
• Trunking (auto)
• Trunk (motorcycle)