Formula One drivers have no spare concentration for operating fiddly controls, or trying to look at small, hidden gauges. Hence the controls and instrumentation for modern Formula One cars have almost entirely migrated to the steering wheel itself - the critical interface between the driver and the car.
Early Formula One cars used steering wheels taken directly from road cars. They were normally made from wood (necessitating the use of driving gloves), and in the absence of packaging constraints they tended to be made as large a diameter as possible, to reduce the effort needed to turn. As cars grew progressively lower and cockpits narrower throughout the 1960s and 1970s, steering wheels became smaller, so as to fit into the more compact space available.
The introduction of semi-automatic gearchanges via the now familiar 'paddles' marked the beginning of the move to concentrate controls as close to the driver's fingers as possible. The first buttons to appear on the face of the steering wheel were the 'neutral' button (vital for taking the car out of gear in the event of a spin), and the on-board radio system's push-to-talk button.
As time went on the trend continued. Excepting the throttle and brake pedals, few Formula One cars have any controls other than those on the face of the wheel. Buttons tend to be used for 'on/off' functions, such as engaging the pit-lane speed limiter system, while rotary controls govern functions with multiple settings, such as the traction control programme, fuel mixture and even the car's front-to-rear brake bias - all functions the driver might wish to alter to take account of changing conditions during the race. Among the most recent additions are the boost button, used to call on the temporary additional power available in cars equipped with a KERS system, and controls for the moveable front wing.
The steering wheel is also used to house instrumentation, normally via a multi-function LCD display screen and - more visibly - the ultra-bright 'change up' lights that tell the driver the perfect time for the optimum gearshift. Race control can also communicate with the driver via a compulsory, steering-wheel mounted GPS marshalling system. This displays warning lights, with colours corresponding to the marshals flags, to alert drivers to approaching hazards, such as an accident, on the track ahead.
The steering wheels are not designed to make more than three quarters of a turn of lock in total, so there is no need for a continuous rim, instead there are just two 'cut outs' for the driver's hands.
One of the most technically complicated parts of the whole Formula One car is the snap-on connector that joins the wheel to the steering column. This has to be tough enough to take the steering forces, but it also provides the electrical connections between the controls and the car itself. The FIA technical regulations state that the driver must be able to get out of the car within five seconds, removing nothing except the steering wheel - so rapid release is vitally important.
Formula One cars now run with power assisted steering, reducing the forces that must be transmitted by the steering wheel. This has enabled designers to continue with the trend of reducing the steering wheel size, with the typical item now being about half the diameter of that of a normal road car.