cover SdF_Rubino 10.2016The paper deals with some methodological and empirical issues related to adjusting the so called IRPET Web Application devised to help appraise investment projects arranged under PPP schemes at the local level as to encompass the building and management of an urban parking lot. A concise overview of parking decisions micro-foundations is coupled by a discussion of the major externalities which arise in the field and by the presentation of the institutional and regulatory framework in place in Italy. The paper then goes on to present the main features  of a would-be routine aimed at expanding the Web Application with a specific focus on a parking lot or facility to be managed under a time based park-and-pay system.