Abstract  Brief encounters between acquainted and unacquainted motorcyclists are enjoyable moments. This truly mobile form of social interaction is difficult to study through traditional ethnographic fieldwork. However, the method is applicable when integrated into a design approach where the participants collaborate to integrate the field study, the design, and the evaluation. This has made it possible to generate a novel mobile service. The service, named Hocman, is a peer-to-peer application with mobile wireless ad hoc networking for PDAs. It enhances brief traffic encounters between bikers by playing a sound clip and automatically exchanging personal HTML pages. We have positively demonstrated through performance tests and field trials that it is successful in doing this, and that bikers enjoy such added value to biking, especially hearing the sound clip when meeting other bikers.