The Department of Sanitation (DSNY) snow removal designations were added to NYCityMap. Snow removal designations determine the snow plowing priority of each City street. The designations in priority order are: primary, secondary and tertiary. Private streets are not handle by DSNY but are shown on the map for completeness. The data is current for the 2011-2012 winter season.
To access the application click here. From this search form on the Severe Weather site, the data will by default be turned on with the legend highlighted and scrolled to the top. To turn the layer directly from NYCityMap, search for a location click Show Additional Data on Map then click in the box next to the Snow Removal layer.