A Comparative Empirical Analysis of Eco-friendly Routes during Peak and Off-peak Hours

Automobile emissions reductions can come from several sources that include more efficient vehicles, cleaner fuels, and eco-friendly routing. Providing information about expected emissions on alternative routes can influence route choice of drivers, encouraging some to take more eco-friendly routes. During off peak hours, when substantial capacity is available, the eco-friendly route is likely to be non-changing. However, during peak periods, with limited additional capacity, the eco-friendliness of various routes may change, depending on traffic congestion. To explore this issue empirically, more than 13.330 km of data were collected using GPS equipped vehicles, in the US and Portugal. Specifically, data were collected in diverse locations: a large metropolitan area of Hampton Roads, VA, USA, intercity region of Oporto –Aveiro, Portugal, and the medium-sized city of Aveiro, Portugal. The results are based on second-by-second vehicle dynamics, using the Vehicle Specific Power (VSP) concept to extract the emissions on various route alternatives between origins and destinations. During peak hours (and off-peak), a selection of eco-friendly routes can lead to significant savings in global pollutants (up to 25% of CO2) and local pollutants (up to 60% for HC, NOX, and CO). Moreover, these savings are expected to be practically unchanged during the peak hours. In some situations the routes that allow more emissions savings are those that cut across urban areas, instead of bypassing them. The implications for future eco-routing systems are discussed.