Traffic plays an important role in urban areas. The ever advancing technology opens new ways to study traffic and its consequences in great detail. Remote sensing is one of these methods; it allows to research traffic from a birds eye view. Applying remote sensing, this paper examines the traffic in the city of Graz using high-resolution Ultracam data. The aim is to find out how accurately the number and the type of the vehicles can be determined with high-resolution aerial photography and additional photogrammetric surface models.The introductory part of the paper focuses on the basic principles and connections between remote sensing and vehicle detection. Different existing methods are examined and compared by the means of several examples. In the following, background data like the Ultracam aerial photographs and the photogrammetric surface models as well as the research area are introduced more closely.The next chapter explains the object based approach used in the practical application. Then, the necessary pre-processing of data will be described and the application of the selected method to various areas of the city of Graz carried out. Finally, the results of the practical trials will be discussed, the research questions answered and suggestions for future research made.