Combining contribution interactions to increase coverage in mobile participatory sensing systems

Participatory sensing systems use people and their smartphones as a sensing infrastructure, and getting people to make contributions remains a critical challenge. Little work details how system designers should combine different interactions to increase coverage of service location. Tiramisu, a participatory sensing system, invites transit riders to crowdsource real-time arrival information by sharing location traces when they commute. We extended this system with a new feature that allows riders at stops to "spot" buses passing by. To better understand the impact of this new feature, we conducted an observational log analysis, examining changes in coverage and user behavior before and after the new feature. Following the addition of the spotting feature, participants' contributions increased coverage (the number of trips with real-time data) by 98%, and they used the app more than twice as much. The addition of the spotting feature was also followed by a significant increase of trace contributions.