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Title:

Empirical Assessment of Turbo-Roundabout Operations on Traffic and Emissions

Accession Number:

01551590

Record Type:

Component

Availability:

Transportation Research Board Business Office

500 Fifth Street, NW
Washington, DC 20001 United States

Abstract:

In the past decade there has been a significant increase in the number of turbo-roundabouts constructed in several European countries. This paper investigates the impact of turbo- roundabouts located in urban areas on pollutant emissions generated from vehicles through an empirical assessment. The research also compares the emissions of vehicles moving through a turbo-roundabout and a conventional multi-lane roundabout. Based on field measurements taken at turbo-roundabouts and multi-lane roundabouts located in Grado (Spain) and Aveiro (Portugal) three representative speed profiles for each speed trajectory type 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 the conflicting traffic flows. The Vehicle Specific Power (VSP) methodology is employed to estimate second-by-second pollutant emissions. This research testes 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). The results show that vehicles emit more pollutants at turbo-roundabouts compared with multi-lane roundabouts regardless of the traffic demands at the entry and the circulating areas. These findings suggest that there are no advantages on implementing turbo-roundabouts from an environmental point of view even the capacity of the intersection is rather below to the maximum.

Supplemental Notes:

This paper was sponsored by TRB committee ADC20 Transportation and Air Quality.

Monograph Accession #:

01550057

Report/Paper Numbers:

15-1532

Language:

English

Corporate Authors:

Transportation Research Board

500 Fifth Street, NW
Washington, DC 20001 United States

Authors:

Fernandes, Paulo
Pereira, Sérgio Ramos
Bandeira, Jorge M
Vasconcelos, Luís
Bastos Silva, Ana
Coelho, Margarida C

Pagination:

20p

Publication Date:

2015

Conference:

Transportation Research Board 94th Annual Meeting

Location: Washington DC, United States
Date: 2015-1-11 to 2015-1-15
Sponsors: Transportation Research Board

Media Type:

Digital/other

Features:

Figures; References; Tables

Geographic Terms:

Aveiro (Portugal); Grado (Spain)

Subject Areas:

Environment; Highways; Operations and Traffic Management; I15: Environment; I73: Traffic Control

Source Data:

Transportation Research Board Annual Meeting 2015 Paper #15-1532

Files:

TRIS, TRB, ATRI

Created Date:

Dec 30 2014 12:34PM