Environmental Performance Assessment of Urban Roundabouts.

To meet continuous and sustainable improvement on road infrastructures, new technologies and smart devices are encouraging the development of a mobile crowdsensing system for collecting and monitoring data to be used in efficiency assessment. In this view, the paper proposes a methodological approach that employs in an integrated way vehicle trajectory data collected in the field, the Vehicle Specific Power methodology and a microscopic traffic simulation model for estimating emissions at urban roundabouts. For a first characterization of the emissive phenomenon reference was made to an existing two-lane roundabout in Palermo, Italy, where vehicle trajectory data were collected using a smartphone app in a test vehicle. The case study addresses the issue of converting existing roundabouts into turbo roundabouts, and gives an insight into how to assess the impacts of alternative designs from an environmental perspective.