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Safety

 

Although cars have become faster, current models are safer than many of those manufactured in previous decades. Modern cars incorporate beams at their front and rear, which crumple progressively in order to absorb energy, while having a strong central cell to protect occupants in the event of a crash.

Braking has greatly improved in recent years and most systems feature servo assistance. This harnesses the vacuum produced by the engine to actuate the brakes, so that the driver does not need to apply an excessive amount of pressure to the pedal.

A further refinement is an automatic braking system. This sophisticated anti-locking device operates in conjunction with the vehicle’s engine management unit, and was initially used on expensive cars to prevent skidding.

 

Electric Cars  
The only vehicle to meet the requirements of the California Clean Air Act is the electric car. This type of car produces no harmful exhaust fumes, and does not absorb power when stationary. In 1996 General Motors became the world’s first major car manufacturer to put a purpose-designed electric car, the EV1, into production.

 

Reducing Car Pollution  
In recent years environmental considerations and growing concern over traffic pollution have had a profound effect on car design. The United States introduced the first regulations on noxious car emissions in 1967; the California Clean Air Act requires that, by 2003, 10 per cent of all new cars sold in that state must have zero exhaust emissions. However, as these restrictions become more rigorous, their effects on the power and efficiency of car engines grow more adverse. Noxious emissions include carbon monoxide, nitrogen oxides, volatile organic compounds, and particulates. In 1986 the Japanese Toyota company introduced the more efficient multivalve twin overhead camshaft engine, a unit more usually associated with high-performance models. This concept has now been widely adopted by the world’s motor industries.

All new cars sold in Europe since 1990 have had to be capable of running on unleaded petrol. Lead has been added to petrol since the 1920s to improve engine performance, but was found to be a health hazard when emitted from car exhausts. In Britain unleaded fuels account for 67 per cent of petrol sales.

Similarly, the exhaust systems of all new cars have had to be fitted with catalytic converters since 1993. In its basic two-way form, the catalytic converter uses platinum and palladium to catalyse the carbon monoxide and hydrocarbons that are produced by the engine’s combustion process into carbon dioxide and water.

Manufacturers are currently undertaking research into "lean-burn" engines, which use less petrol and therefore produce a lower level of harmful emissions. The diesel-engined car has grown in popularity but recent evidence shows that the minute specks of soot, called particulates, that it produces are likely to exacerbate conditions such as bronchitis and asthma, mostly in city centres.

 

Performance and Four-Wheel Drive  
 From the 1970s the performance of such vehicles had also been enhanced by the development of the turbocharger. Driven by otherwise wasted exhaust gases, it is a small, high-revolution pump that forces air into the cylinders at pressure and is invariably used in conjunction with an intercooler. This cools incoming air to make it denser, further increasing engine power.

Performance cars were usually front-engined (and sometimes rear-engined) until the appearance, in 1966, of the Lamborghini Muira, which had a mid-located power unit. This meant a better-balanced car, but at the expense of greater interior noise and loss of rear seating.

Yet a further development in performance was the four-wheel drive with superior road holding. This was a luxury fitment until the arrival, in 1980, of the Audi Quatto, a make that had also introduced, in 1976, the petrol-fuelled five-cylinder engine. Four-wheel drive had already been incorporated in the cross-country Land Rover, its design inspired by the American Jeep. It first appeared in 1948 and paved the way to the better-equipped Range Rover.