Dear Rabbi Lamm: The days and hours which alternate-side-of-the-street parking are to be effective are determined by the New York City Department of Sanitation. That Department requests the New York City Traffic Department to authorize such regulations. After installation, the Traffic Department sees to it that these regulations are in proper condition. If you require the information as to why Saturdays were reinstated as alternate-side-of-the-street parking days, we recommend that you write to the New York City Department of Sanitation at 125 Worth Street.We are sorry that we could not be of further aid to you in this matter.Very truly yours,SAMUEL HOCHSTEINDirector of Highway Patrol