Auto theft is still 'big business,' despite efforts to catch offenders. Recovery rates for stolen vehicles have declined; cars often are stripped of salvageable parts or sold to 'chop shops'

It was a bright Saturday afternoon. A Boston businessman drove his 1978 Oldsmobile to a nearby shopping mall, parked and locked it, and hustled off to do an errand. When he returned in a half hour, the car was gone. Five days later the vehicle, or its burned-out shell, was found five miles away on a secluded road.

A rainy morning, a few months later, a retired salesman heading off for church found his Mercury Comet had been broken into, the radio ripped out and the ignition disabled.

These are but two of thousands of car-theft stories scribbled each day on police blotters across the United States.

The problem, although hardly a new one, continues to grow in dimensions, especially in value of stolen vehicles, accessories, and contents.

The number of reported thefts of cars, trucks, and motorcycles dropped slightly last year in comparison with 1981 - from 1,073,988 down to 1,048,310. Even so, 1 in every 158 registered motor vehicles in the nation was burglarized or stolen in 1982. And the overall car-theft rate in '82 was one every 30 seconds, according to the National Auto Theft Bureau (NATB), an agency supported by the insurance industry.

Based in Illinois, the NATB notes that altogether there were 3,798,976 vehicle-involved larcencies, an average of one for every 484.5 registered vehicles, during the 12 months that ended last Dec. 31.

While some cars are taken by youthful offenders for so-called ''joy rides,'' the lion's share of stolen vehicles, accessories, and contents are by professional thieves, reports NATB president Paul W. Gilliland. He points out that despite considerable law-enforcement effort, stealing cars is ''big business, and it is getting bigger.''

Total value of stolen vehicles, accessories, and contents throughout the United States last year was $4.5 billion.

The vehicle theft problem, which has nearly quadrupled nationally over the past 25 years, is particularly critical in Massachusetts. Here, the rate of larcenies per 100,000 vehicles has continued to top all other states and is more than twice the average of all 50 plus the District of Columbia.

During the past five years, for example, more than 290,000 stolen vehicles were reported in the commonwealth. In 1982 alone the figure was 55,005, or an average of 968 per 100,000 registered vehicles, according to the Federal Bureau of Investigation's (FBI) uniform crime report released earlier this fall.

Thus, Massachusetts retains one of its least-cherished distinctions: the car-theft capital of the nation.

Ranking behind the Bay State on the latest list are New York at 780.8, Rhode Island - 737.7, Michigan - 691.7, California - 665.5, New Jersey - 628.8, Alaska - 594.3, and Texas - 579.1.

The safest states, in terms of fewest percentage of vehicles stolen last year , are South Dakota at 118.4, North Dakota - 180.3, Mississippi - 153.6, Iowa - 173.7, and Idaho - 174.9.

Determined to curb Massachusetts' stolen vehicle problem, Gov. Michael S. Dukakis has formed a 25-member auto theft strike force. The two-year program - involving representatives of state, metropolitian, and Boston police, the state registry of motor vehicles, and the FBI - will zero in on both the offenders and the main causes of such crimes.

''For car thieves - both professional and amateur - stealing vehicles has been a low-risk venture with a high rate of return,'' asserts Governor Dukakis, who holds that the time has come to shift from studying the problem to cracking down on offenders.

Anti-car theft measures on Massachusetts books include mandatory prison sentences for repeat offenders and for those convicted of auto larceny fraud.

Considerable attention is expected to be focused on the Greater Boston area, which ranked second only to the Houston metropolitan area in its 1982 stolen vehicle rate. (According to US Justice Department figures, for the first six months of this year Boston's auto theft rate has jumped 5.7 percent.)

New York City ranked third with a 1982 auto theft rate of 1,271.3 per 100,000 registered vehicles. New York is followed by Detroit with 1,242.7; Jersey City, N.J., with 1.239.7; Los Angeles-Long Beach with 1,104.2; and Cleveland with 1. 037.3.

There is more to stolen car reports than data reveal. According to Massachusetts state police Maj. Peter Agnes, who is heading the new strike force , some vehicles have been taken and disposed of so that the owner can collect insurance. He says this type of fraud most often occurs when the auto is worth less than its insured value or when the owner is behind on payments.

Particularly prevalent in recent years has been the theft of cars to be stripped of salvageable parts, later to be sold to so-called chop shops or burned.

This situation has contributed substantially to the low recovery rate of stolen vehicles. Nationally, in 1958, at least 92 percent of the 282,791 vehicles taken were later found. Last year, only 54 percent of the 1,048,310 stolen vehicles were recovered, including a large portion damaged so badly they were of no use to the owners.

What might be a significant step toward putting chop shops out of business is the indelible stamping of the vehicle identification number (VIN) not only on engines, now required in most states, but on other major parts of autos and trucks.

Legislation to accomplish this now is pending in both branches of Congress, but prospects for passage are not bright since carmakers have been resisting the measure.

One of these measures, sponsored by US Sen. Charles H. Percy (R) of Illinois, would require the marking of up to 14 parts, such as fenders, doors, trunk, and steering mechanism, be imprinted with the VIN. The total cost could not exceed $ 10 per car.

A similar bill, being pushed in the House by US Rep. Timothy Wirth (D) of Colorado, has been referred to four separate committees.

Considerably more promising is an anti-car theft measure which is attached to the tariff law amendment bill, which cleared the House in June and awaits Senate floor action in January. It would require those exporting a used car to provide the US Customs Service with the VIN in advance of the shipment date, and the information would be available to law enforcement officials and groups like the NATB. This, it is felt, could greatly curb, or even halt, the stealing of vehicles for resale outside the United States.

Under current law, reports to customs officials need not be filed until 72 days after shipment, explains Chuck Taylor of the National Association of Independent Insurers, one of the groups interested in the measure's passage.

Although conceding there still is a long way to go before stolen car traffic will be slowed, auto insurance industry officials say they are encouraged that in 1982, for the second straight year, the number of stolen vehicles across the nation was down, if only slightly.

This modest improvement is attributed to toughened laws enacted in several states and to stricter enforcement of existing laws.

The average value of cars stolen in 1982, according to the NATB, was $3,545, up from $3,173 in 1981. The average value of stolen accessories was $214 last year, up from $192 in 1980. Contents burglarized in 1982 were worth an average

An increasing number of anti-theft davices for cars are generally credited with making it harder for would-be ''car-nappers,'' but those close to the scene , like police Major Agnes, caution that in many instances they tend only to slow down such crimes.

As soon as carmakers or others come up with new security devices, auto thieves figure a way to get around them, laments Thomas Carr of the Motor Vehicle Manufacturers Association of the United States.

Police, insurance industry officials, and others concerned with putting vehicle thieves out of business say the best protection against theft is to make sure the keys are out of the ignition, the car is locked, and it is parked in a well-lighted area.

Especially vulnerable are autos parked on lightly traveled streets or in shopping malls, where, as Governor Dukakis puts it, ''car thieves with their own shopping lists are stealing cars on order through them, thanks to sophisticated car-theft rings.''