Measuring the Reliability of Methods and Algorithms for Route Choice SetGeneration: Empirical Evidence from a Survey in the Naples Metropolitan Area

Background:Route choice set definition is a very sensitive phase of the route choice simulation. Several heuristics, generally based on shortest path algorithmrepetition, give as output choice sets that are very large, lading to questions about their behavioural consistency. Objective:This paper proposes a comparison of the main route choice set generation methods, contrasting the results of the commonly implemented heuristicswith the revealed choice sets of a sample of employees and students moving within the Metropolitan Area of Naples. Methods:We described the data collection process and provided a statistical analysis of the sample data. In addition, since coverage measures andperformance indicators, usually applied in the literature, do not take into account any possible biases related to the generated choice set cardinality.The current work proposes an analysis of the coverage of routes that are generated by the heuristics towards the revealed routes. Results:We observed that when the heuristics did not provide overlapped routes, although giving higher network coverage, they introduced a highernumber of links not belonging to any observed route. In general, this may cause significant network loading errors. Therefore, the quality of amethod for choice set generation should be measured as a function of the trade-off amongst network coverage and network loading bias due toexcessive cardinality of the generated choice-sets. Conclusion:We found the randomization method, which is also less computational demanding, provided the best trade-off amongst network coverage andnetwork loading bias