Simulation of urban environments requires the knowledge of the vehicle directional noise emission characteristics, in order to be more accurate and confer more authenticity to the 3D audio. This paper presents a methodology to extract the directional sound energy pattern, emitted by a moving vehicle, using a simple microphone array. The method consists in recording the vehicle pass-by sound with a set of two horizontal sensors and, based on the spectrogram and on a modified direction of arrival algorithm, determine the energy spectrum according to the direction between the source and the receivers. The proposed method is initially investigated with simulated data, where the analysis signals are generated by simulating the passage of a sound source with a known directivity pattern. Using white noise as source signal, the proposed algorithm was able to recover the directional pattern with errors up to 1 dB. The method is then applied to real measurements, conducted in a controlled environment, where four vehicles passed through the sensors at different speeds. As there were no ground-truth for such evaluation, the spectral characteristics of the directional data were compared to similar data in the literature. The results pointed to a convergence between estimated and expected data, showing that the proposed method is capable of extracting horizontal directional information from passing vehicles, which can be applied to determine the general directional emission pattern of vehicle categories or models, for application in acoustic virtual environments.