H4

H4, H04, or H-4 may refer to:

Biology and medicine

Technology

Transport

Automobiles and roads

Aviation

Headlamp

A headlamp is a lamp attached to the front of a vehicle to light the road ahead. While it is common for the term headlight to be used interchangeably in informal discussion, headlamp is the term for the device itself, while headlight properly refers to the beam of light produced and distributed by the device.

Headlamp performance has steadily improved throughout the automobile age, spurred by the great disparity between daytime and nighttime traffic fatalities: the US National Highway Traffic Safety Administration states that nearly half of all traffic-related fatalities occur in the dark, despite only 25% of traffic travelling during darkness.

Other vehicles, such as trains and aircraft, are required to have headlamps. Bicycle headlamps are often used on bicycles, and are required in some jurisdictions. They can be powered by a battery or a small generator.

History of automotive headlamps

Mechanics

The earliest headlamps were fueled by acetylene or oil, and were introduced in the late 1880s. Acetylene lamps were popular because the flame is resistant to wind and rain. The first electric headlamps were introduced in 1898 on the Columbia Electric Car from the Electric Vehicle Company of Hartford, Connecticut, and were optional. Two factors limited the widespread use of electric headlamps: the short life of filaments in the harsh automotive environment, and the difficulty of producing dynamos small enough, yet powerful enough to produce sufficient current.

H4 (classification)

H4 is a Paralympic cycling classification. The UCI recommends this be coded as MH4 or WH4.

Definition

PBS defined this classification as "Athletes with higher function and stability are in classes H2 and H3, and H4 is for athletes who can kneel on the handcycle." In 2012, UCI defined this classification broadly as: "Paraplegic with impairments corresponding to a complete lesion from Th11 or below,· Double below or Double through knee amputee".The Telegraph defined this classification in 2011 as "H 1-4: Athletes on handcycles, with lower limb dysfunctions and limited stability"

The cycle

This classification can use ATP3 knee-seat cycle that is forward leaning on a rigid frame.

Classification history

Cycling first became a Paralympic sport at the 1988 Summer Paralympics. In September 2006, governance for para-cycling passed from the International Paralympic Committee's International Cycling Committee to UCI at a meeting in Switzerland. When this happened, the responsibility of classifying the sport also changed.