T The government through Perum Perumnas is trying to build core housing for the lower middle class. One example is Sector 3, Parung Panjang, Bogor Regency. However, the main road in this residential area causes high traffic frequency. Over time, this housing estate has experienced changes in building functions, such as becoming restaurants, clothing stores, and grocery stores. This research aims to study these changes and the factors that cause them. The method used in this research is spatial analysis with overlay and buffer techniques, and data processing using ACRGIS. The results of the analysis show that residential house owners change the function of the building to commercial trade without the appropriate permit. This change mainly occurs in residential units along the main road, reaching 61%. The change in function can occur because it is influenced by factors such as the lack of availability of trade facilities, strategic location and access, and weak control because the change does not have an appropriate permit.