Abstract: Beamforming is a standard method of determining the Direction-of-Arrival (DoA) of wave energy to an array of receivers. In the case of acoustic waves in an air medium, the array would comprise microphones. The angular resolution of an array depends on the frequency of the data, the number of microphones, the size of the array relative to the wavelengths in the medium, and the geometry of the array, i.e., the positions of the microphones in relation to each other. The task of finding the right balance between the aforementioned parameters is microphone-array optimization. This task is rendered even more complicated in the particular context of sound classification and localization for self driving cars as a result of the design limitations imposed by the automotive industry. We present a microphone array optimization method suitable for designing arrays to be placed on vehicles, which applies beamforming using the Radon transform. We show how our method produces an array geometry with reasonable angular resolution for audio frequencies that are in the range of interest for a road scenario.