Boston — * In Michigan, liquor-related car crashes involving teen-agers dropped 18 percent in 1979. * In Massachusetts, fatal alcohol-connected highway accidents among teen-agers declined 18.5 percent during the past two years.
These improved safety records are credited in at least some quarters to passage of state laws raising the minimum legal drinking age.
Despite continuing, sometimes vigorous, resistance from civil libertarians and others who would not deny young adults access to liquor, at least a dozen states in the past five years have banned alcoholic beverages for 18-year-olds, and -- in some places -- 19- and 20-year-olds as well.
In the past 12 months, four states -- Florida, Georgia, New Jersey, and Rhode Island -- increased the legal drinking ages for all types of liquor. And a fifth state, Virginia, has greatly restricted beer sales to 18-year-olds.
The Virginia measure, signed into law Feb. 21 by Gov. John Dalton, forbids anyone under 19 from buying beer at liquor package stores. Other types of alcoholic beverages remain out of bounds for all 18- through 20-year-olds in the state.
Some 48 other proposals for lowering the legal drinking age by at least one year have been under consideration in 1981 legislative sessions in 22 states from Vermont to Hawaii.
More than half of these measuress still are alive, although only a few appear to have made much progress.
In Texas, two bills to hike the age minimum from 18 to 19 are before a conference committee assigned to work out differences.
The Vermont House of Representatives similarly has approved a drinking age measure, but one that the state Senate seems unlikely to go along with since it would ban 18-year-olds from drinking at home but permit them to be served liquor at bars. The latter inconsistency was inserted by its foes in hopes of scuttling the bill. Despite their efforts, however, the legislation cleared the Vermont House on a 73-to-72 roll call.
Texas and Vermont are among eight states where liquor of all types can be bought by 18-year-olds. The others are Connecticut, Hawaii, Louisiana, New York , West Virginia, and Wisconsin. In addition, these older teen-agers can purchase beer with 3.2 percent alcohol content in Colorado, Kansas, Ohio, and South Dakota, and beer and wine in the District of Columbia, Maryland, Mississippi, North Carolina, and South Carolina. These states and the District of Columbia, however -- like Virginia -- restrict other types of liquor to persons 21 or older.
Illinois also has a liquor age minimum of 21 -- except for beer and wine, which can be purchased by 19-year-olds.
Except for Michigan, none of the 12 states that have increased their legal drinking ages since 1976 went back to age 21, where they were prior to the early 1970s. Even so, the move apparently is popular with Michigan voters, who affirmed their satisfaction with it by better than 3-to-2 last November in the face of a statewide referendum to lower the age to 19 again.
Much of the support for reversing the field and bringing the drinking age minimums to at least 19 has come from school administrators, for whom liquor in the hands of 18-year-old high-school seniors has caused serious problems, such as drunkenness in classrooms and at school functions.
Youths able to legally buy alcoholic beverages are blamed for giving them to schoolmates below the minimum age.
While almost nobody suggests that raising the drinking age, even all the way to 21, would completely take liquor out of the hands of adolescents, boosters of the current legislation are optimistic that substantial progress in this direction can be expected.
Teen-age drinking problems are underscored by a recently released study by a North Carolina-based research organization for the National Institute on Alcohol Use and Alcoholism, which concluded that one-third of American high school students are problem drinkers.
Three out of every 10 of these were termed moderate to heavy drinkers and 87 percent of those in grades 10 through 12, in the nearly 5,000-pupil national sampling, reported having had at least one drink of liquor in the previous year. Forty-nine percent said some of their drinking had been in cars; 23 percent admitted driving after drinking.
Critics of raising the liquor age contend it will not reduce teen alcohol problems and question the accuracy of statistics that indicate fewer highway traffic deaths involving liquor and youthful drivers.
Much of the opposition to a higher liquor age in states like Connecticut and Vermont stems from a concern that those too young to get a drink in their states would cross the border to New York, where 18-year-olds can buy drinks, and in the process perhaps get into auto accidents.
Three other states abutting New York now have higher drinking ages -- New Jersey (19), Massachusetts (20), and Pennsylvania (21).
Besides New Jersey, whose new law took effect last January, six others have hiked the minimum liquor age to 19 in the past few years: Minnesota (1976), Iowa and Montana (1978), Tennessee (1979), and Florida, Georgia, and Rhode Island ( 1980). Rhode Island is scheduled to advance the age to 20 on July 1. Legislation to delay this or repeal the measure outright is awaiting lawmakers' consideration.
Maine in 1977 and Massachusetts and New Hampshire in 1979 increased their liquor age minimum from 18 to 20.
Michigan now is among 14 states that ban liquor for persons under 21. The others, all of which kept this level despite the earlier trend, are Arkansas, California, Indiana, Kentucky, Missouri, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, Pennsylvania, Utah, and Washington.
Delaware is the only state outside New England with a legal minimum drinking age of 20.
Fourteen states now have age 19 drinking minimums. Beside those already mentioned, they are Alabama, Alaska, Arizona, Idaho, Nebraska, and Wyoming .