The technology of Global Positioning Systems (GPS) provides new ways for collecting information about travel behavior. When it is used in combination with an electronic travel diary, valuable information of high quality about travel behavior becomes available. To learn about the possibilities of this new technology, a pilot study involving 151 people was performed in the Netherlands. What makes this pilot unique is the monitoring of all modes of travel, not just travel by motorized vehicles. The findings suggest that although it is possible to monitor all travel modes, data quality differs among them. The GPS device registered nearly all car driver trips, compared to half of the tram and train trips. When trips are registered, public transport trips are registered with a higher accuracy level than car trips. For specific trips, respondents did not use the equipment because of the burden placed on them or because of a lack of time. This was especially the case for walking, cycling, public transport, shopping trips, and visits. Concerning route, distance, and trip segments, it can be concluded that although valuable information is collected, there remain many difficulties to be overcome.