EU Science Hub

Traffic Simulation: Case for guidelines

As part of the MULTITUDE project a survey was undertaken in 2011 regarding how practitioners used traffic simulation models. This revealed that 19% of those polled, conducted no calibration of their models, and of those that did, only 55% used guidelines during this process. To investigate this issue further a second survey was performed to identify which documents were being used most, and areas of concern, where it was felt that further/better guidance was needed. In this report we have examined these areas, their strengths and weaknesses, and have isolated five gaps, where improvements would allow better overall guidance to be produced: • Data, where a greater quality and quantity needs to be available not only for the performance of calibration and validation but also to allow a greater understanding of the variability of conditions likely to be encountered. • Standardisation and definitions in basic methodology, where greater clarity is required as to what (for example) MoPs are acceptable and more importantly, essential. • Illustration, Comparison and Evaluation, with a greater need for comparable case and meta studies. • Variability, where guidance is needed as to which (for example) parameters effect differing macroscopic observables, the so called ‘hierarchy of parameters’ which can be uncovered through greater sensitivity and uncertainty analysis. • Assisted calibration, where automated codes would aid in sensitivity analysis, batch analysis and, through reduced project ‘run times’, potentially an increase in the number of runs undertaken. In addition, and through stakeholder engagement, it has been revealed that there are a number of non technical issues slowing advances in this area which are related to a lack of clarity of the purpose of guidelines, their target/required audience and simple economics. This has lead to the production of five recommended cross-cutting actions: A. Agencies need to consider a better communication programme as to what is expected of contractors as regards adherence to their guidelines, when and how to depart from them. B. A greater education is needed among practitioners as regards simulation and traffic fundamentals and as such there may be a need for a core qualification of some description. C. Agencies need to ensure that contractual expectations as regards guideline observance are not in contradiction with budgetary constraints. D. Manufacturers need to be encouraged to provide software to expedite all stages of the simulation project life cycle. E. A heavily practitioner centric, pan-European forum, is needed for the ongoing debate of simulation issues with, as far as possible face to face meetings and the performance of short term working groups.