Examination of Attributes and Value of Ecologically Friendly Route Choices

Significant progress has been made recently in the development of ecologically friendly routing (ecorouting) navigation systems that suggest a travel route that uses the least amount of fuel or that produces the least amount of emissions. Previous research has shown that these ecoroutes are not always the same as the shortest or the fastest route. However, other questions that need further investigation to understand the attributes and value of these ecoroute choices better remain. For example, how often are the ecoroutes different from other routes (e.g., the routes with the shortest distance or the shortest time)? When the ecoroutes are not the same as the fastest route, what is the trade-off between the amount of fuel and emission savings and the added travel time? The objective of this study was to examine these questions systematically through the use of real-world case studies in the Los Angeles, California, metropolitan area. The attributes (i.e., distance, travel time, and fuel consumption) of two routes for the same trip were first compared. This comparison revealed the relationship and trade-off between the route attributes; the trade-offs proved the validity of the ecorouting concept. On the basis of an extensive simulation, an analysis of the trade-off between fuel savings and increased travel time for ecoroutes and for the fastest routes was performed. The results show that the elasticity of fuel for travel time ranges from -0.63 to -0.90. For trips shorter than 10 mi, the ecoroute would save more fuel but take more time as the trip distance increases.