SmartRoadSense is a collaborative project aimed at monitoring road surface conditions exploiting the sensors, i.e., accelerometers and GPS, commonly embedded in most mobile devices. Given a smartphone connected to the cabin of a car travelling on a road, the SmartRoadSense app analyzes the accelerometer signals and extracts a roughness index (based on a linear predictive coding analysis) characterizing the quality of the road. The roughness index and the corresponding GPS data are periodically sent to a central server, which associates the data to a specific road/location and aggregates data coming from different users. The resulting data are freely available for graphical visualization and download. Activated in Italy in February 2015, in nine months SmartRoadSense has already covered more than 24,000 km, which correspond to around 5% of the Italian road network. The demo aims at illustrating the signal processing analysis performed in SmartRoadSense app and showing how data are aggregated on central server. Participants will be able install and test the app on their smartphones and to follow all processing steps. More information about SmartRoadSense is available at http://smartroadsense.it/.