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Diagram of an engine using pressurized lubrication
Wikimedia Commons has media related to Internal combustion piston engine lubrication systems.
Surfaces in contact and relative motion to other surfaces require lubrication to reduce wear, noise and increase efficiency by reducing the power wasting in overcoming friction, or to make the mechanism work at all. At the very least, an engine requires lubrication in the following parts:
Between pistons and cylinders
Big end bearings
Valve gear (The following elements may not be present):
Timing chain or gears. Toothed belts do not require lubrication.
Economics of car use
The costs of car usage, which may include the cost of: acquiring the vehicle, repairs and auto maintenance, fuel, depreciation, driving time, parking fees, taxes, and insurance,5 are weighed against the cost of the alternatives, and the value of the benefits ? perceived and real ? of vehicle usage. The benefits may include on-demand transportation, mobility, independence and convenience.7 During the 1920s, cars had another benefit: "couples finally had a way to head off on unchaperoned dates, plus they had a private space to snuggle up close at the end of the night."48
Similarly the costs to society of encompassing car use, which may include those of: maintaining roads, land use, air pollution, road congestion, public health, health care, and of disposing of the vehicle at the end of its life, can be balanced against the value of the benefits to society that car use generates. The societal benefits may include: economy benefits, such as job and wealth creation, of car production and maintenance, transportation provision, society wellbeing derived from leisure and travel opportunities, and revenue generation from the tax opportunities. The ability for humans to move flexibly from place to place has far-reaching implications for the nature of societies.8
About Occupational driving - Wikipedia:
Work-related roadway crashes are the leading cause of death from traumatic injuries in the U.S. workplace. They accounted for nearly 12,000 deaths between 1992 and 2000. Deaths and injuries from these roadway crashes result in increased costs to employers and lost productivity in addition to their toll in human suffering.5 Truck drivers tend to endure higher fatality rates than workers in other occupations, but concerns about motor vehicle safety in the workplace are not limited to those surrounding the operation of large trucks. Workers outside the motor carrier industry routinely operate company-owned vehicles for deliveries, sales and repair calls, client visits etc. In these instances, the employer providing the vehicle generally plays a major role in setting safety, maintenance, and training policy.5 As in non-occupational driving, young drivers are especially at risk. In the workplace, 45% of all fatal injuries to workers under age 18 between 1992 and 2000 in the United States resulted from transportation incidents