Transumo (Transition Sustainable Mobility, www.transumo.nl) is a national Dutch research program that aims to initiate and support a transition to a sustainable mobility system that supports an international competitive position of the Dutch economy (¢â‚¬Ëœprofit'), that respects the environment (¢â‚¬Ëœplanet'), and that offers high quality accessibility and mobility for people and the goods they need (¢â‚¬Ëœpeople'). Transumo is funded for 50 percent by the Dutch government and for 50 percent by the private sector and by knowledge institutions with a combined budget of 60 Million Euros spread over five years. One of the key themes in Transumo is to explore and capitalize the (widely acknowledged) potential of Intelligent Transport Systems, Services and Solutions (ITS) to enable, facilitate or possibly even force transitions to a more sustainable mobility. The Advanced Traffic Monitoring (ATMO) project (www.atmo.tudelft.nl), with a budget of 2.5 ME is one of the (over 20) research projects, which has contributed (and still contributes) to this goal. Within ATMO, the TRAIL research school, two universities (Delft University of Technology and the University of Twente), various public organizations (the Ministry of Transport, the Province of South¢â‚¬ÂHolland and the municipalities of Delft and Utrecht) and a number of representatives from the private sector (TNO, Vialis, Siemens and ARS T&TT) collaboratively address the question "how to translate large amounts of raw traffic data from all sorts of sensors and systems into useable and meaningful information for traffic information, sustainable traffic management and control?". In the context of sustainability, this entails not just "classic" traffic data and information, such as average speed, volume, or delay and travel time, but also more diffuse concepts such as congestion severity, travel time reliability, traffic safety and environmentally related quantities. This paper will overview the scientific and practical results obtained within ATMO from its inception in 2004 until 2008, and provide a brief outlook on the anticipated results in its final year (2009) and beyond, where the paper will also outline further avenues for both research as well as collaboration between partners. The paper is organized as follows. The next section provides a first birds¢â‚¬Âeye overview of the ATMO project. The research objectives, scope and structure are discussed and a brief sketch of the various subprojects is given. In the section thereafter, a selection of three subjects addressed in ATMO are discussed in more detail, these are, travel time prediction; travel time reliability; and real time monitoring of vehicle emissions. The paper closes with a discussion on the various lessons learned throughout the project and avenues for further research.