Detalhes bibliográficos
| Autor(a) principal: |
Fernandes, Paulo |
| Data de Publicação: |
2016 |
| Outros Autores: |
Pereira, S. R.,
Bandeira, J. M.,
Vasconcelos, Luís,
Bastos Silva, Ana |
| Tipo de documento: |
Artigo
|
| Idioma: |
eng |
| Título da fonte: |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
| Texto Completo: |
http://hdl.handle.net/10400.19/3157
|
Resumo: |
This paper addresses the impact of turbo-roundabouts located in urban areas on pollutant emissions using field measurements of vehicle activity data and road congestion levels. The research also compares the emissions of vehicles moving along a turbo-roundabout and a conventional multi-lane roundabout. Based on field measurements taken at turbo-roundabouts without curb dividers located in Grado (Spain) and multi-lane roundabouts in Aveiro (Portugal), three representative speed profiles for each speed trajectory were identified: no stop (I), stop once (II), and multiple stops (III). This study also develops discrete models for turbo-roundabouts and multi-lane roundabouts in which the relative occurrence of those speed profiles is expressed as a function of the entry and conflicting traffic flows. The Vehicle Specific Power (VSP) methodology is then employed to estimate second-by-second pollutant emissions. This study tests the hypotheses that emissions are impacted by the differences in: 1) the characteristics of speed profiles in each movement; 2) the volumes of entry and conflicting flows; 3) the overall saturation level; and 4) the transportation facility considered (turbo-roundabout /multi-lane roundabout). Considering the selected case studies and traffic demands, vehicles at turbo-roundabouts generated more emissions (15-22%, depending on the pollutant) than multi-lane conventional roundabouts, especially under medium and high congested levels. These findings suggest that there are no advantages in implementing turbo-roundabouts from an environmental point of view, even in no saturated conditions. |