Coming of age
In the United States, teenagers are allowed to drive at 16 in all states except New Jersey, which requires drivers to be 17 and older, and sometimes receive the responsibility of owning their own car. Teenagers may drive at age 15 in Idaho and Montana. At 16, teenagers are also old enough to donate blood and work in most establishments. At 18 one is legally considered an adult and can vote and join the military. The legal age for purchasing and consuming alcohol and recreational marijuana, the latter of which is only legal in the District of Columbia, Colorado, Oregon, Washington, California, Hawaii, Massachusetts, Nevada, and Alaska, is 21. The legal age for purchasing and consuming tobacco products is 18 in most states; 19 in Alabama, Alaska and Utah; and 21 in California, New Jersey, Oregon, Hawaii and Maine. Multiple localities have also raised the minimum purchase age independent of state laws.
King v Jones
But it was argued for King that the South Australian "Age of Majority (Reduction) Act 1970" had altered the age at which people in South Australia are legally considered adults from 21 to 18. Lionel Murphy also suggested that "adult person" really meant a person considered to be mature, and that in 1972, a person over 18 years old was considered mature, at least in South Australia. Murphy also raised the examples that people over 18 can, by law, marry, be tried as adults under Australian criminal law, and can serve in the Australian Defence Force. Murphy cited a range of dictionaries, including legal dictionaries, which gave the definition of adult as a person who is considered mature.