Boston — Small children are to be seen but not hurt -- this is the philosophy, if not the theme, of a car-safety drive fast catching on with lawmakers around the nation.
Within the past six months, nine states, more than double the previous total, have mandated the use of car-safety seats for children under four or five years old. Similar measures are pending in at least seven others.
Supporters claim the various laws and proposals can protect little ones from what is by far the major cause of death among babies and young children. National Safety Council officials estimate that 1,500 children under age five are killed annually in car crashes.
But foes are concerned that mandating car-safety seats is an intrusion on parental rights and will force the poor to buy special seats they cannot afford.
''I have some real problems with the bill,'' says Ohio state Sen. Ben M. Gaeth, chairman of the Agriculture, Commerce, and Labor Committee, where a child car-seat measure is pending. ''I am concerned about regulating young parents and (police) stopping a car (just because) a young mother has a baby in her arms whom she is nursing.''
The Defiance, Ohio, Republican says parents with several children have contacted him, wondering if all the necessary restrainer seats would fit in their compact cars.
Dr. Robert S. Sanders disagrees. ''We must immunize our young children against this epidemic,'' says the Rutherford County, Tenn., health officer whose early efforts and persistence led to passage of this nation's first such law -- in Tennessee -- in 1977.
He declines to speculate how many infants and toddlers may have escaped car crashes because of the statute and its rigid enforcement. But he cites ongoing studies in various states that indicate small child crash injuries are reduced by 80 percent and deaths by 90 percent.
In his home state, Dr. Sanders notes that during the three years prior to passage of the measure small child vehicle crash fatalities averaged 20 to 25 a year. But since 1979, when tough enforcement began, the number of infants and tots killed in vehicle accidents has dropped each year from 22 to 10 in 1981.
Although the Tennessee law was the first of its kind in the United States, similar requirements have been established for some time in Australia, New Zealand, and much of Western Europe.
Nationwide in 1978, the last year for which official federal statistics are available, such accidents resulted in the death of 1,287 children aged 1 to 5 -- more than double the number of fatalities from the next leading cause within that age group.
Boosters of such legislation credit much of the current momentum in the US to the strong support of the American Academy of Pediatrics (AAP), which has made it a top priority, and the backing of other groups like the National Safety Council and the Insurance Institute for Highway Safety, based in Washington, D.C.
Car-crash tests conducted for the latter ''have demonstrated a great deal of violence takes place within the vehicle even at speeds of 20 miles an hour,'' says Albert Benjamin Kelley, the institute's senior vice-president. A small child, unless secured properly, can be catapulted from the seat.
At least 30 infant seats and fastening devices now on the market meet essential child safety standards, notes Marsha Grobman, the AAP project coordinator.
Child car-restraint measures are in effect in Kansas, Massachusetts, Michigan , Minnesota, New York, Rhode Island, Tennessee, and West Virginia. Similar laws become operational within the next 13 months in Alabama, Connecticut, Florida, Kentucky, Nebraska, North Carolina, Virginia, and Wisconsin. The Nebraska measure, however, applies only to those who operate day-care centers, not parents or guardians.
Besides the 16 states with such measures on their books, three others -- California, Indiana, and Maine -- have provided educational programs to alert parents and others to the need for using such protective seats.
Before its strengthening last year, the original Tennessee law deemed acceptable the holding of an infant by an accompanying adult. ''That was all we could get,'' says Sanders, noting how the original legislation took two years to win approval of state lawmakers, and then only by a narrow margin.
Violators are subject to penalty in all but four states -- Kansas, Kentucky, Minnesota, and North Carolina. In the latter, however, a penalty will only be experimented with in the third year of the program. Fines range from $10 to as high as $200, depending on the state and whether it is a repeat violation.
The intent is not to punish but to provide maximum protection to small children, Dr. Sanders says. Usually, penalties are waived if the parent or guardian can later show proof of purchase of a restraining device.
The new Virginia statute, to take effect next January, provides that money collected through fines is to be used to purchase the necessary restrainers for loan to those unable to afford them. In Tennessee, all state troopers carry extra child-safety seats with them, which are lent to motorists until they can purchase such equipment.
Meanwhile, proposals for mandating their use are being considered in California, Delaware, Illinois, New Jersey, Ohio, Oklahoma, Pennsylvania, and Washington, D.C., where hearings are to begin shortly.