Washington witnessed a dramatic decrease in traffic deaths last year despite the swelling of normal motorist and pedestrian ranks by droves of Bicentennial visitors, D.C. police have reported.

The total of 60 traffic fatalities logged by police in the city during 1976 was down sharply from the 74 deaths that occurred in 1975 and represented the lowest annual tally in 15 years. It was less than half the yearly figures for 1967, 1968, 1969 and 1970.

The total for traffic injuries in the city last year, at 7,163, was the lowest since 1969.

The total deaths here last year included 34 pedestrians or others not in vehicles, among them three persons who were killed while sitting at a table playing cards when a truck smashed into their house.

Total traffic accidents in the District slipped to 22,588 last year form the 1975 figure of 24,053.

More aggressive law enforcement and public education programs were key factors in the lower death, injury and accident statistics for the Bicentennial year, according to D.C,. Deputy Police Chief Ernest Prete, who commands the traffic division, and Capt. Brian Traynor who heads its traffic operations branch.

They reported a total of 6,973 arrests last year for pedestrian violations such as jaywalking or disobeying "Walk/Don't Walk" signals, up sharply form the 2,926 arrests in 1975 abd 1,274 in 1974.

The total of 186,471 arrests last year for speeding, improper turns and other "moving violations" was 13 per cent above the year-earlier 165,652 and nearly half again the 1974 arrest total of 126,814.

Reflecting a crackdown on motorists driving under the influence of alcohol, arrests for this offense soared last year to 2,572 up 59 per cent from 1975 and 175 per cent form 1974.

Police traffic officials set up a special alcohol enforcement unit last year after finding that drinking was a factor in about half of all traffic accidents. With a grant from the U.S. Department of Transportation, Capt. Traynor began equipping traffic cruisers with videotape recorders and training officers to recognize the less obvious signs of drunk driving.

Police officers were also given additional training in how to prepare drunk-driving cases for presentation in court with an eye to boosting conviction rates.

As for public education, D.C. police with federal grant funds equipped a van with a public address system and labeled the vehicle with current pedestrian traffic statistics. They used the van to patrol areas rated dangerous for pedestrians, broadcasting safety messages and enforcing the law where necessary.

Outside the District, Maryland State Police Supt. Thomas S. Smith said the total of 673 traffic deaths throughout his state last year was the lowest figure in 12 years.

The Virginia state police superintendent, Col. H.W. Burgess, said last year's total of 1,015 traffic deaths in that state was the fourth year-to-year decrease in a row, a trend unprecedented since the state began keeping traffic records. The 1976 death toll was the lowest since 1963.

Col. Burgess said Virginia's enforcement of the 55 miles per hour speed limit was an important factor in reducing traffic fatalities.

Traffic fatalities since 1956 are as follows:(TABLE) 1956(COLUMN) 57 1957(COLUMN) 73 1958(COLUMN) 63 1959(COLUMN) 63 1960(COLUMN) 72 1961(COLUMN) 60 1962(COLUMN) 65 1963(COLUMN) 98 1964(COLUMN)115 1965(COLUMN)101 1966(COLUMN) 97 1967(COLUMN)131 1968(COLUMN)127 1969(COLUMN)127 1970(COLUMN)121 1971(COLUMN) 96 1972(COLUMN) 73 1973(COLUMN) 76 1974(COLUMN) 78 1975(COLUMN) 74 1976(COLUMN) 60(END TABLE)