THIS SATURDAY, as you step off the curb into any D.C. street to make the daring journey to the other side, the right of way will belong to you, not to the automobiles you may encounter at the intersection.

Perhaps you thought your rights as a pedestrian in this city, if not exactly constitutionally guaranteed, were nevertheless inalienable. But in fact the D.C. law protecting pedestrians against motorists was neither explicit nor vigorously enforced. There was a question, for instance, whether pedestrians had the right of way in unmarked crosswalks. Such legal ambiguities, coupled with some awful driving habits, have led motorists to usurp the roadways, while people on foot remain stalled and frustrated.

This forbidding atmosphere for pedestrians would have been reason enough to amend the law. But the deaths last November and January of several people who were simply attempting to cross the street, as well as an increase in the number of complaints from citizens, prompted the D.C. Council to rewrite it altogether. The new law, the "Pedestrian Protection Act of 1987," which goes into effect Saturday, strengthens the rights of pedestrians and increases the penalties for injuring or killing them. The act:

makes explicitly clear that pedestrians have the right of way in both marked and unmarked crosswalks;

requires vehicles to yield to pedestrians in any portion of the crosswalk (the old law permitted motorists to pass on one side of the roadway as pedestrians entered an intersection on the other side);

allows pedestrians who commence crossing the street with a "WALK" signal to complete that crossing even if the signal changes to "DON'T WALK" (the old law required pedestrians to turn back or to seek a safety island);

increases the penalty for failing to yield the right of way to a pedestrian and for colliding with a pedestrian from $50 to a fine of not more than $500 or imprisonment for not more than 30 days, or both; and

states that anyone driving in a careless, reckless or negligent manner who kills a pedestrian in a marked or unmarked crosswalk will be charged with negligent homicide, an offense that carries a penalty of up to five years' imprisonment and/or up to a $5,000 fine.

The D.C. Council's Committee on the Judiciary says that one purpose of the law is to "change the driving habits of motorists in the District of Columbia." It may take some time before motorists in these parts reflexively yield to people at intersections who are just waiting for an opening in the traffic. But the new law, along with stepped-up enforcement, should lead many to modify their behavior. Let's hope so.