Sure, the library is not directly connected to CARLA.
The ad_rss library is designed to be even completely independent from an actual map representation.
The ad_rss_map_integration library is demonstrating a possibility on how on could derive the required input to RSS based on vehicle states and underlying map data. For this, the ad_map_access library is used which is published under the github carla project. But also that map library is completely independent from CARLA simulator itself -- it's just reusing the OpenDRIVE reader code from CARLA. Some tools around OpenSCENARIO creation/editing are also relying on that ad_map_access library.
The only tight connection to CARLA is the actual integration of the RSS Sensor within CARLA which makes use of the libraries from with ad-rss-lib.
Can the Ad-rss-lib be used in a different environment other than carla?