I. Introduction
The last European Parking Association (EPA) report estimates a total of 230 million of parking spaces in the EPA countries [1]. In addition, the United States parking spaces are estimated to be 800 million [2]. However, finding a parking spot is still a challenging task in most metropolitan areas. According to [3] drivers spend an average of 20 minutes searching a parking space. This time can increase to 40 minutes in European cities such as Madrid [4]. The generated traffic resulting from this parking search affects to the environment, increasing the emissions of CO2 [5]. If we take into account the growth projections of the world's population (9 billion by 2044) [6], city parking and its environmental impact are almost certainly going to get worse.