Fuzzy Sets and Systems for a Motorway

Microscopic simulation modelling has recently become attractive to researchers in traffic engineering as it appears to offer a cost effective and ‘safe’ way of investigating Intelligent Vehicle-Highway System (IVHS) at a fundamental level. However, the deterministic approach used assumes a consistency of behaviour which may severely detract from model validity. This may be overcome by using a ‘fuzzy’ approach to describe drivers’ decisions. This paper describes the development of the Fuzzy LOgic motorWay SImulation Model, (FLOWSIM). Emphasis is placed on the research undertaken to establish fuzzy sets and systems for motorway driving behaviour models, the collection of data on appropriate motorway driving behaviour, fuzzy sets and systems calibration, and model validation. Model validation results have shown that the fuzzy model (FLOWSIM) can closely replicate real systems and in test cases have performed better than some common deterministic models such as the ‘GHR’, ‘Gipps’ and ‘MISSION’ models.