Traffic accidents claimed fewer lives in Washington last year than in any of the 56 years since the city began recording such statistics.

Fifty-one men, women and children, including 24 pedestrians, were killed on the city's streets in 1978, according to the traffic division of the D.C. police department. It was the third consecutive year in which the number of traffic deaths declined in the city.

A three-year crackdown on drunk driving, a strict program to curb jaywalking, improved street signs and better maintenance of the city's streets all contributed to the record low number of deaths in 1978, said Capt. Wayne Layfield, head of the traffic division.

To battle the two great traffic killers, drunk drivers and speeders, the city recently purchased a $29,700 van equipped with a machine that measures a driver's alcoholic intake, and with radar and a jail cell.

More than 50 percent of last year's fatal accidents involved drivers or pedestrians who had been drinking, police said.

Before 1978, the record year for the fewest traffic deaths was 1956, when 57 were killed, of whom 36 were pedestrians. The most traffic deaths occurred in 1934 when 135 people died, including 95 pedestrians.

There were 58 traffic deaths in 1977, 60 in 1976 and 74 in 1975.

There have been no deaths so far in 1979.

Paul S. Meads, 68, of 6645 Georgia Ave. NW, became last year's first fatality when he died on Jan. 23 from injuries suffered Nov. 3, 1977, when he was hit by a car while trying to cross Georgia Avenue near Webster Street NW.

On Dec. 30, Christina Hall, 30, and Leo Thomas, 63, both of 1210 Stevens Rd. SE., became the last two fatalities when they were killed while attempting to cross Suitland Parkway near Firth Sterling Avenue SE, one of the city's most dangerous intersections.