4 On the Need of Trustworthy Sensing and Crowdsourcing for Urban Accessibility in Smart City CATIA PRANDI, SILVIA MIRRI, STEFANO FERRETTI, and PAOLA SALOMONI, University of Bologna Mobility in urban environments is an undisputed key factor that can afect citizens’ well-being and quality of life. This is particularly relevant for those people with disabilities or with reduced mobility who have to face the presence of barriers in urban areas. In this scenario, the availability of information about such architectural elements (together with facilities) can greatly support citizens’ mobility by enhancing their independence and their abilities in conducting daily outdoor activities. With this in mind, we have designed and developed mobile Pervasive Accessibility Social Sensing (mPASS), a system that provides users with personalized paths, computed on the basis of their own preferences and needs, with a customizable and accessible interface. The system collects data from crowdsourcing and crowdsensing to map urban and architectural accessibility by providing reliable information coming from diferent data sources with diferent levels of trustworthiness. In this context, reliability can be ensured by properly managing crowdsourced and crowdsensed data, combined when possible with authoritative datasets, provided by disability rights organizations and local authorities. To demonstrate this claim, in this article we present our trustworthiness model and discuss results we have obtained by simulations. Categories and Subject Descriptors: C.2.4 [Computer-Communication Networks]: Distributed Systems General Terms: Design, Management, Measurement Additional Key Words and Phrases: Crowdsourcing, Crowdsensing, Urban Accessibility, Credibility, Trust- worthiness ACM Reference format: Catia Prandi, Silvia Mirri, Stefano Ferretti, and Paola Salomoni. 2017. On the Need of Trustworthy Sensing and Crowdsourcing for Urban Accessibility in Smart City. ACM Trans. Internet Technol. 18, 1, Article 4 (October 2017), 21 pages. https://doi.org/10.1145/3133327 1 INTRODUCTION As world populations concentrate in cities, mobility in urban environments is becoming one of the most prominent and interesting research felds in the smart city context. A well-known def- nition of smart city is provided in Gifnger et al. (2007), and it says that a smart city is “a city well performing in a forward-looking way in economy, people, governance, mobility, environment, and living, built on the “smart” combination of endowments and activities of self-decisive, independent Author’s addresses: C. Prandi, S. Mirri, S. Ferretti, and P. Salomoni, Department of Computer Science and Engineering, University of Bologna, Mura Anteo Zamboni 7, 40126, Bologna, Italy; emails: {catia.prandi2, silvia.mirri, s.ferretti, paola.salomoni}@unibo.it. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for proft or commercial advantage and that copies bear this notice and the full citation on the frst page. Copyrights for components of this work owned by others than the ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specifc permission and/or a fee. Request permissions from permissions@acm.org. © 2017 ACM 1533-5399/2017/10-ART4 $15.00 https://doi.org/10.1145/3133327 ACM Transactions on Internet Technology, Vol. 18, No. 1, Article 4. Publication date: October 2017.