Formula 1: Engineering safety at 200mph
In the 10 years to 1972, there were five crashes for every four Formula 1 Grand Prix events. Accidents were almost three times as common by the turn of the centuryi .
The difference was, no drivers died.
Formula 1 has been, and probably always will be, a dangerous sport. Teams spend hundreds of millions of dollarsii on the best drivers and fastest cars that FIA regulations allow, with cars accelerating faster than space shuttles to top speeds of more than 200mphiii.
But safety has improved since the heady 1970s, when drivers such as James Hunt - whose rivalry with champion Niki Lauda was portrayed in the movie Rush - famously raced hungoveriv.
Nine driversv and six spectatorsi died in Formula 1 Grand Prix events between 1970 and 1979, prompting new safety regulations that defined seatbeltsvi, crumple zones and a near-indestructible core called the monocoque.
Consequently, there have been no driver deaths in F1 cars at Grand Prix events since 1994vii.
The Fédération Internationale de l'Automobile (FIA) presides over an evolving set of rules that ensure a minimum standard of safety in Formula 1 and defines the playing field for engineers each year.
FIA rules introduced safety walls in the 1970s, drug tests, crash tests and on-site medical centres in the 1980s, and the Formula 1 safety car in 1992vi.
Cockpits were redesigned in 1971 so drivers could be rescued within five seconds, which, with new fire-resistant clothing, improved their chances of survivalvi. Fire extinguisher regulations were tightenedviii, and to reduce the risk of a fire, the FIA added safety foam to fuel tanks which are within crash- and fire-resistant structures.
This year's race cars and their drivers must together weigh a minimum of 702kg - almost a third more than the 1970 minimum. Heavier cars go slower than lighter ones; the increased weight limit encourages teams to use more protective casing in their carsix, and curbs the practice of having drivers lose weight to gain a competitive edgex.
New materials have improved safety as well as performance, with strong, rigid, lightweight and moldable carbon fibre compositesxi replacing the aluminium alloy of the 70s.xii Modern Formula 1 cars are made almost entirely out of carbon fibrexiii.
The carbon-fibre monocoque, which comprises the cockpit and safety cell, is designed to be as strong as possible, with a 6mm bullet-proof layer to protect drivers from debris, and crash-protection structures that deform to absorb energy in an accidentxiv.
Changes to the Formula 1 rulebook have shifted engineers’ focus to various parts of the car, producing some incredible innovations in the name of speed.
In the 1970s, a majority of teams used a 450-horsepower Ford Cosworth DFV engine so the competition was all about the best driver and the most manoeuvrable carxv. Lotus pioneered aerodynamic ground effects, using side skirts and a contoured underbody to create a downforce that improved traction so drivers could take corners at higher speedsxvi.
Elf Tyrrell took a different approach to improving traction with its six-wheeled P34 in 1976xvii. The FIA effectively put an end to six-wheeled cars and ground effects in 1983, over logistics and safety concernsxviii.
Turbocharged engines dominated the late-'70s and '80s, reaching 1400 horsepower by the time the FIA banned turbocharged cars in 1989xix, believing them to be too powerful for existing racetracksxx.
Today's race cars are powered by what the FIA now calls a "Power Unit" instead of an engine, to account for 2014 regulation changes that introduced new, more fuel-efficient hybrid engines. By replacing the former standard 2.4-litre V8 engines with 1.6-litre hybrid V6 engines, the FIA said it was "coming into line with carmakers' everyday production models"xxi.
The FIA's new green focus could be a huge help to mainstream electric cars by sparking the development of new technologies that - like push-button ignition, roll cages, and rear-view mirrorsxxii - have trickled down from the racetrack to everyday passenger vehicles.