On-the-fly generalization, denotes the use of automated generalization techniques in real-time. This process creates a temporary, generalized dataset exclusively for visualization, not for storage or other purposes. This makes the process well suited to highly interactive applications such as online mapping, mobile mapping and SOLAP. BLG tree is a spatial hierarchical structure widely used in cartographic map generalization and particularly in the context of web mapping. However, this structure is insufficient in the context of SOLAP applications, because it is mainly dedicated to the geographic information processing (geometric features), while SOLAP applications manage a very important decision information that is the measure. In this paper, we propose a new structure, SOLAP BLG Tree, adapted to the generalizaion process in the SOLAP context. Our generalization approach is based on this structure and uses the simplification operator. Combining the topological aspect of geographical objects and the decisional aspect (the measure).Our experiments were performed on a set of vector data related to the phenomenon of road risk.