An approach is provided for building single-path communication signal map data for road links. The approach involves, for example, using, by one or more processors, map data and/or vehicle sensor data to make a determination that one or more single-path communication signals are detectable on a particular road link or on one or more portions of the particular road link. The approach also involves, based on the determination, generating or storing, by the one or more processors, a road-link map attribute indicating that one or more single-path communication signals are detectable on the particular road link or on the one or more portions. The approach further involves, based at least on the road-link map attribute, providing, by the one or more processors, coverage information indicating that one or more single-path communication signals are detectable on the particular road link or on the one or more portions.