The long hood of a locomotive is usually about as tall as the cab roof in order to fit the large prime mover and its related subsystems. Originally the short hood of the locomotive was the same height, which is referred to as a "high-nose" or, confusingly, "high short hood." Starting in the mid to late 1950s, the height of the short hood was reduced to increase visibility, creating a "low-nose" or "low short hood" locomotive. Some locomotives that were originally built with a high nose were later modified to have a low nose. Lately it has become common to make the short hood not only lower but also full-width, creating a wider nose which is usually referred to as a "North American Safety Cab" or Canadian comfort cab.