How sustainable is route navigation?: a comparison between commercial route planners and the policy principles of Road categorization

In-Vehicle route planning is used to support a driver’s route choice and to guide a driver to a destination. The suggested route takes less account of environmental aspects, which could lead to cut-through traffic. The Flanders Spatial Structure plan describes certain categories of roads for the optimization of the road network based on selectively prioritizing either accessibility or liveability. The aim of this paper is to examine to what extent route planners apply the principles of this (policy-made) road categorization while calculating a route. Three route planners were used to calculate routes. These routes were compared to a ‘desired’ route which follows the principles of the spatial structure plan. This paper will describe the in-depth analysis of this research. The results show that differences in road usage are apparent. These deviations are mostly found in the use of low and/or high categorized roads. Especially roads of the lowest category are frequently used by route planners to guide through-traffic without considering the lower function of these roads. For some of these suggested routes, the desired route is a feasible alternative.