Boston — Teen-age drivers and liquor - often-lethal companions on American roadways - may soon have a tougher time getting together.
Although progress toward keeping them apart is a lot slower than many highway safety officials, law-enforcement officers, and concerned citizens would like, within recent months there has been at least modest headway on several fronts:
* Statutes raising the minimum legal drinking age from 18 to 19 have been enacted in Connecticut and New York; and Maryland has moved to take beer and wine out of the hands of 18- to 20-year-olds (21 is still the legal drinking age for other liquor).
* Penalties for selling liquor to teen-agers were stiffened in Massachusetts under a measure signed into law recently by Gov. Edward J. King.
* High school students in several states have formed Students Against Driving Drunk (SADD) chapters, bent on encouraging their peers not to drink and drive.
The New York legislation, signed into law June 7 by Gov. Hugh Carey, is viewed by some as significant since the state is the nation's second largest in population, and the minimum liquor age there has been 18 since the end of prohibition nearly a half century ago.
Passage of the law, effective Dec. 7, brings to 19 the number of states that over the past five years have lifted their drinking age. Those 18 states are among 28 which during the early to mid-1970s responded to the ''old enough to fight, old enough to drink'' youth slogan of the Vietnam war by lowering their drinking age for some or all alcoholic beverages from 21 to 18 or 19.
But efforts to reverse that drinking age drop have been under way in most of those states and seem likely to continue as lawmakers either concede their earlier action was a mistake, or yield to constituent pressure to get liquor out of the hands of teen-agers.
Spurring the push are not only headline-grabbing road accidents involving young drunken drivers, but insurance industry and highway-safety studies indicating that up to 60 percent of all crashes involving 16- to 20-year-old motorists are liquor-related.
Besides Connecticut, Maryland, and New York, the states that have raised their drinking age by at least one year since 1977 are Florida, Georgia, Illinois, Iowa, Maine, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, New Jersey, North Dakota, Rhode Island, Tennessee, Texas, and Virginia.
Sixteen states now have set their minimum drinking age at 21. Five, all but one of them in New England, have set it at 20. Sixteen have a drinking age of 19 , and five retain 18 as the minimum age. The remaining eight states and the District of Columbia permit 18-year-olds to buy beer and wine but allow other forms of liquor only for those over 20.
A study by the University of Michigan's Highway Safety Research Institute noted a 20 percent decline in the number of liquor-related crashes involving drivers under 20 in 1979 - the year after the Michigan drinking age was raised back up to 21 from 18.
That report, released last November, concluded that ''the net effect of restoring the drinking age to 21 was 1,100 fewer accidents,'' notes Alexander C. Wagenaar, who conducted the study.
The study also monitored the positive results from the 1978 drinking age hike from 18 to 20 in Maine. There, the total of property damage-producing accidents involving 18- and 19-year-olds dropped 17 percent.
While funds for followup studies have not been available, Dr. Wagenaar says the reductions in liquor-related accidents in both Maine and Michigan ''appear to be holding constant.'' The University of Michigan study, he explains, took into consideration other factors such as the state's economic decline, which presumably affected the amount of driving done.
Dr. Wagenaar sees as especially significant the fact that liquor-related accidents among drivers under 21 declined at a greater rate than among older drivers, or among drivers in other states which have not raised the drinking age.
Gov. Richard A. Snelling vetoed in April a measure passed by the Vermont General Assembly to raise the drinking age, and instead announced plans recently for legislation to restrict liquor purchases by persons under 21 to those who have completed a state-run alcohol education program.
Even youths from out of state, such as New York where the drinking age will be 19 and Massachusetts and New Hampshire where it has been 20 since 1979, would have to meet this requirement to obtain needed identification cards.
The promise of such legislation is viewed in some Vermont political circles as designed to prevent the Snelling veto from becoming an issue in the fall gubernatorial campaign.
Mr. Snelling and other critics of simply lowering the drinking age, contend that it is not the answer to the problem. They question whether such measures would discourage young drinkers from getting behind the wheel.
Besides neighboring Vermont, which some advocates of raising the drinking age warn could become overrun with teen-agers from neighboring states in quest of liquor, only four states - Hawaii, Louisiana, West Virginia, and Wisconsin - allow 18-year-olds to purchase alcoholic beverages of all kinds.
The drinking age was an issue in the 1978 Massachusetts gubernatorial campaign, in which then governor Michael S. Dukakis, who had recently vetoed legislation to raise the drinking age, was upset in the Democratic primary by now Governor King, a staunch booster of the measure.
Mr. Dukakis, who currently is seeking to regain the governorship from his successor, partially attributed his 1978 unseating to his position then on the drinking age question.
Since the 1979 passage of the Massachusetts statute bringing the liquor age from 18 to 20, the number of highway accidents involving drivers under 20 who had been drinking has declined by nearly 50 percent, according to the Department of Public Safety.
It says that in the six years (1973 to 1978) in which those 18 and 19 could drink legally in the commonwealth, an average of 106 of these youths were killed in liquor-related accidents. Last year, the third since the minimum age went back up to 20, there were 56 such fatalities.
The Bay State's newest alcohol control measure, on the books less than a month, raises the fine for selling alcoholic beverages to anyone under age 20 from $200 to $1,000.
Besides the higher drinking age, the decline in liquor-related accidents is attributed in part to the efforts of SADD members whose chapters have sprung up in several parts of the state during the past nine months.
The group, since its inception at Wayland (Mass.) High School last fall, has spread across the commonwealth and into several other states, encouraging fellow teen-agers and others not to both drink and drive.
Massachusetts public safety officials are particularly pleased that during the recent high school prom season there were no liquor-connected fatal accidents involving youths.
''The young people are getting the message across,'' says Robert Anastas, the Wayland public health teacher who first set the educational and lobbying program's wheels in motion.