This work, part of the European project ‘Intelligent Roads’, aims to achieve real-time data collection and innovative methods for road traffic monitoring, focusing on some performance indicators: travel time and traffic density. Data fusion provides a consistent and comprehensive picture of network conditions, based only on available data sources: No sensor expense, but improved data quantity and quality. Two main sources are used: Classical loop detectors and probe vehicle reports (floating car data, toll stamp reports). Data is collected on several European sites. Very encouraging results are obtained on performance indicators. Data fusion will be applied to safety indicators too.