Implication of Eco-Driving at a Single Lane Roundabout

Eco-driving applications in the context of signalized intersections have been extensively discussed in previous studies. However, very few of them examined the impacts of eco-driving on the operations and especially, on emission characteristics in a roundabout. This paper attempts to explore the eco-driving impacts on vehicle emissions generated in the situation of a single-lane roundabout through a driving simulator-based test. Twenty subjects were recruited to drive through the roundabout with the aid of an in-vehicle advance voice warning system, which provides advance voice warning messages on an approaching roundabout at different locations, from 150 m to 50 m distance to the stop line of the roundabout. Results showed that, the carbon dioxide emissions in the scenario with an earlier warning message in 150 m trigger distance are less than the one with latter warning message in 50 m trigger distance. Compared with baseline scenarios without warning messages, an early warning message could induce the less emissions in most scenario groups. It is concluded that, under certain circumstances, vehicle emissions can be reduced if the drivers start to decelerate at an approaching distance of 150 m to a roundabout.