The minimum and usual mainlane width is 12 ft [3.6 m]. The number of lanes required to accommodate the anticipated traffic in the design year is determined by the level of service evaluation as discussed in the Highway Capacity Manual.
Adj. groovy is 1853 in lit. sense of of a groove; 1937 in slang sense of excellent, from jazz slang phrase in the groove (1932) performing well (without grandstanding).. As teen slang for wonderful, it dates from 1944; popularized 1960s, out of currency by 1980.
It originated as a word in the 1960s gay slang language Polari--isn't that interesting enough?) The two great exceptions are snafu (situation normal: all fucked up) and fubar (fucked up beyond all recognition), which grew out of the military's RFA (rage for acronyms) in World War II.