As my competitor in covering Metro and other transportation agencies a few years back, Tom Crosby always was given to hyperbolic prose in his stories for The Washington Star.

He's crossed the street, to become top press spokesman for the Potomac division of the American Automobile Association, but he hasn't lost his touch for dramatization.

"The sounds of 20,000 marching feet will resound throughout the nation's capital," his latest news release declares, "as the 51st annual school safety patrol parade makes its way up Constitution Avenue on Saturday . . . from 10 a.m. to 2 p.m."

Tom's arithmetic is solid: The next paragraph assures us that the 20,000 noisy feet belong to 10,000 youngsters from 185 patrol units in the District of Columbia, Maryland and Virginia who will be in the parade along with more than 100 bands, drill teams, floats and other entries. The reviewing stand will be opposite the Washington Monument grounds.

Among the marchers will be Joelle Patton, 12, a Beltsville seventh-grader who won the AAA school safety patrol lifesaving award for saving the lives of three kindergarteners while on safety patrol duty.

Another who will attend the parade is Billy DeRosa, a patrol captain when the area's first school safety patrol was organized at Washington's Brightwood School in 1926.

A word of warning to Virginia motorists: If you want to drive into downtown during parade hours on Saturday, avoid the 14th Street bridge--or use the Third Street NW (I-395) tunnel to get there.