How to Adjust Cost-Benefit-Analyses for Evaluation of V2I Technologies?

Abstract

Methods and specific procedures for Cost-Benefit-Analyses (CBA) of transportation infrastructure projects are well established in many countries. Nevertheless they are tailored for appraising civil engineering constructions which lead to significant changes in traffic flow patterns which can be predicted with macroscopic models. The paper describes which adjustments to the CBA procedure are necessary and how they are implemented to evaluate upcoming applications of Intelligent Transportation Systems (ITS) in general, and those using Vehicle-to-Infrastructure (V2I) communication in particular. First, the effect predictions of different scenario cases must be based on a microscopic traffic simulation where the ITS / V2I functionalities are modelled in a way that results comply with the CBA structure. Therefore the macroscopic sub-models for each beneficial criterion are replaced by microscopic ones. New approaches to noise and accident prediction are considered as well. The high time discretisation rate of results enables better extrapolation from a few simulated hours up to annual outcomes. Furthermore the combination of multiple technological scenarios within the appraisal period is necessary. The sensitivity to different cost unit rates and especially to those of time savings is discussed, since ITS applications may enable only seconds per user to be saved and thus might not contribute to this important beneficial criterion. An approach of ITS costs determination and an alternative to the net present value as rating indicator are given due to their uncertain and fuzzy nature. The considerations are backed by examples of national and EU R&D projects where different CBA procedures were applied.