As in many countries, audience measurement for outdoor advertising media in the Netherlands is a hot topic. The different strategies of outdoor contractors are a complicating factor, since some of them sell billboards one-by-one according to the advertisers wishes, while others offer fixed Products consisting of standard packages of clearly defined sites spread across the country; the methodological problems in each case being quite different. While awaiting the results of SUMMO negotiations, Alrecon Media, a representative of the second kind of contractor, asked Inter/View Nederland to develop a research programme that could supply media planners with data on their products. In 1988 and 1989 several Rondjes Nationaal of different media (Buses, Bus shelters. Railway Station Postering and Billboards), were measured. The methodology was quite different from the more usual OSCAR-method, and also different from Route Reconstruction methods. In order to achieve fast results, a Diary Panel method using mechanical counters was set up for four weeks. Respondents were selected from the SummoScanner database. As a result of questioning the same respondents once again, a single source database is now available for use in computerised media planning. For the first time there is now the possibility of comparing different types of media, deluding outdoor media, on the basis of single source research data.