Car controls

From Infogalactic: the planetary knowledge core
Jump to: navigation, search
In the Ford Model T the left-side hand lever sets the rear wheel parking brakes and puts the transmission in neutral. The lever to the right controls the throttle. The lever on the left of the steering column is for ignition timing. The left foot pedal changes the two forward gears while the centre pedal controls reverse. The right pedal is the brake.

Car controls generally refers to controls in cars and most other powered road vehicles, including trucks, buses, and specialized vehicles (e.g. heavy equipment), that are used for driving, parking, and passenger comfort and safety. Modern car controls are now standardised, but this was not always the case. Controls are evolving in response to new technologies, for example the electric car.[clarification needed]

Since the car was first invented, many of its basic controls have become fewer and simpler through automation; for example, all cars once had manual, physical controls for the choke valve, clutch, ignition timing, and a crank instead of an electric starter. However, new controls have also been added to vehicles, making them more complex. Examples include air conditioning, navigation systems, on-board computers, and in car entertainment. Another trend is the replacement of physical knobs and switches with touchscreen controls. These may be limited to secondary controls as in BMW's iDrive and Ford's MyFord Touch, or may substitute an entire set of controls, as seen in vehicles by Tesla Motors.

While the following components usually apply to most road vehicles, there are exceptions, in which the controls may be located and operated differently from road vehicles (such as motorcycles, whose throttle is controlled by a hand lever and the gear shift by a pedal). Additionally, some characteristics of road-vehicle controls may be found in rail vehicles; for example, some trams or light rail vehicles (most notably the PCC streetcar) use automobile-style pedals to control the speed, usually in conjunction with a dead man's switch.


1969 Citroen DS Pallas interior with hydraulic gear selector mounted top right of steering column with a single spoke steering wheel. Note the so-called mushroom brake pedal. (The pedal on the left is the parking brake).

The first automobiles were steered with a tiller. In 1894, Alfred Vacheron competed in the Paris–Rouen race with a Panhard et Levassor with a steering wheel, which is thought to be the earliest deployment of the wheel.[1] From 1898, Panhard et Levassor cars came with steering wheels.

Steering wheels for passenger automobiles are generally circular, mounted to the steering column. Where cars drive on the left side of the road, the steering wheel is typically on the right side of the car, and vice versa.

Power steering makes it easier to turn the wheels. Power steering has mostly been hydraulic, but is now being replaced by electrical systems.


Hanging pedals in a Subaru Legacy. From left to right: foot rest, clutch, brake, gas.
Standing pedals in a Saab Sonett (clutch, brake, throttle)

An automobile or other road vehicle may have two to three pedals. They can be either "hanging" from the firewall (bulkhead) or "standing" on the floor; the latter is usually used in trucks and buses. The arrangement is the same for both right- and left-hand traffic. From left to right:

  • normally operated by the left foot:
  • normally operated by the right foot:
    • brake pedal, which is sometimes wide and elevated above the car floor
    • throttle (known as the "accelerator" or "gas pedal"), controls fuel and air supply to the engine. It is usually narrow and close to the floor allowing the driver's heel to rest on the floor. It has a fail-safe design in that it automatically returns to the idle position when not depressed by the driver.

Since the right foot is normally used (for the accelerator or brake) there is no foot rest on the right, even in cars with cruise control. The left foot only has to operate the clutch intermittently (or has no function in an automatic vehicle), so sometimes a foot rest is provided to the left of the pedals. The left foot also operates the parking brake pedal if so equipped, while applying the brakes with the right foot.

Some drivers practice left-foot braking, however it has proved to be difficult to train the left foot to skilfully press the brake pedal thus bringing the vehicle to a smooth stop; instead, the outcome is usually a sudden stop. Another technique that eases pedal operation on vehicles is heel-and-toe.


Early cars such as the Ford Model T had a hand lever to control the throttle.[2] Later cars used both a foot pedal and a hand lever where the hand lever set the minimum throttle, an early form of cruise control. Modern cruise control was invented in 1948[3] and is usually operated via buttons on the steering wheel. Many vehicles now include pedals with electric adjustment, a modern iteration of a manual adjustment system available sporadically since the 1950s.

Cars used to be equipped with a manual choke valve on the carburetor. Modern cars had an automatic choke, and today the control is unnecessary as fuel injection has supplanted carburettors. Another adjustment once made manually was ignition timing.[4]

Early Chevrolets had the starter pedal to the right of the accelerator. Because it was difficult to operate this and the throttle pedal, there was a secondary Throttle control knob on the dashboard.

Other vehicles

Heavy vehicles on caterpillar tracks such as bulldozers or tanks may have two brake pedals; for the left and right side tracks respectively. These vehicles do not have a clutch pedal but two manually operated levers; the clutches and brakes are used for differential steering.

In a bulldozer the gas pedal operates in an opposite way to an automobile; depressed pedal = idle, released pedal = full open throttle.

A twin engined wheel tractor-scraper has two gas pedals next to each other; one for the front engine and one for the rear engine.


A floor-mounted gear lever in a modern passenger car with a manual transmission

Vehicles are equipped with a transmission or gearbox to change the speed-torque ratio and the direction of travel: forward or reverse. In electric vehicles clutches and multi-speed gearboxes are not required, as electric motors can drive the vehicle both forward and reverse from zero speed and typically operate over a wider speed range than combustion engines.[5] In some four-wheel drive vehicles there is a gear lever that engages a low-ratio gearbox, used on tough terrain. Other levers may switch between two- and four-wheel drive, or engage differential locks.

Some cars have a freewheel that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. Saab used a freewheel system in their two-stroke models and maintained it in the Saab 96 V4 and early Saab 99 for better fuel efficiency, but at the cost of engine braking. Some cars, such as the Rover P4, included a manual switch to engage or disengage the freewheel.[6]


Manual transmissions feature a driver-operated clutch and gear stick. Historically, cars had a manual overdrive switch.


The desire for driver convenience has led to the widespread implementation of the semi-automatic transmissions, automatic transmissions and CVTs. Some automatic transmission vehicles have extra controls which modify the choices made by the transmission system depending on engine and road speed. Automatic transmissions traditionally have had a straight pattern beginning at the most forward position with park (which locks up the transmission), and running through reverse, neutral, drive (all gears available), and then the lower gears (often two or three more positions, each locking out a successive upper gear), with the rear-most position allowing first gear only.

Signalisation and lighting

Cars include controls for headlamps, fog lamps, turn signals and other automotive lighting. Turn signals are activated by the driver on one side of the vehicle at a time to advertise intent to turn or change lanes toward that side.[7] Electric turn-signal lights date from as early as 1907.[8] The modern turn signal was patented in 1938, and later most major automobile manufacturers offered this feature.[9] As of 2013 most countries require turn signals on all new vehicles that are driven on public roadways. The turn signal lever is usually activated by a horizontal lever protruding from the left side of the steering column.


Cars include a variety of instruments to indicate driving parameters and the state of the mechanics, for example a speedometer, odometer, fuel gauge, temperature gauge, and tachometer. Early cars were often equipped with an ammeter to measure the performance of the electrical system, but in modern cars the gauge has been replaced by a warning light.


1917 Packard crankholder

Before the advent of the starter motor, engines were started by various methods, including wind-up springs, gunpowder cylinders, and human-powered techniques such as a removable hand-crank. These were difficult and dangerous. The first electric starter was installed on an Arnold.[10] In 1911 Charles Kettering and Henry Leland invented and filed U.S. Patent 1,150,523 for the first electric starter in America. Starters were first installed on the Cadillac Model Thirty in 1912.

Before Chrysler's 1949 innovation of the key-operated combination ignition-starter switch,[11] the starter was often operated by the driver pressing a button mounted on the floor or dashboard. This type of control has now returned because of the use of keyless entry.


  1. Duncan, H.O. (1927). The World on Wheels - Volume I. Paris. pp. 456–457, picture of the Vacheron-Car on p. 457.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  2. "The Ford Model T". Retrieved 29 March 2014.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  3. Speed control device for resisting operation of the accelerator. Ralph R. Teetor. US-Patent 2519859 A
  4. "1928 Chevy Owner's Manual". Retrieved 30 March 2014.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  5. "2007 Tesla roadster". 2006-07-19. Retrieved 2011-09-01.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  6. "Rover P4 Manual". Retrieved 29 March 2014.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  7. Federal Motor Vehicle Safety Standards; Lamps, Reflective Devices, and Associated Equipment: Final Rule 12/04/2007
  8. U.S. Patent 912,831
  9. U.S. Patent 2,122,508
  10. G.N. Georgano (1985). Cars: Early and Vintage, 1886–1930. London: Grange-Universal. ISBN 1-59084-491-2.
  11. "Chrysler Family Debut", ''Popular Mechanics'' April 1949, p.122. Retrieved 2013-09-30.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>