David Jeffery

Data requirements and sources for the calibration of microscopic motorway simulation models

At higher levels of demand, the flow of traffic on motorways can become unstable with flow breakdowns and an increase in accident risk. Improvements in capacity and stability may be achieved by modifying behaviour or control, and this process is the target of research into preventative IVHS measures. However, to understand the effects it is necessary to develop and use appropriate microscopic simulation models. To calibrate a microscopic simulation model, a large amount of checking should be performed to ensure that the model behaves correctly, at both a microscopic and a macroscopic scale. This procedure is not straightforward as microscopic data is complex to obtain and interpret, due to the diversity of the information required, and because many parameters used in model formulation are not directly related to easily observable quantities.<<ETX>>

Validation of capacity reductions in traffic monitoring systems

Both planned and unplanned events can reduce the capacities on roadways and result in congestion and delay. Currently, there are no complete and reliable sources which can be used by traffic operators to estimate capacity reductions. On many occasions, operators have to estimate capacity reductions using a large degree of subjectivity. This paper describes a methodology developed to validate capacity reductions from data collected within the traffic monitoring system. Methods for the determination of normal capacity, short-term and long-term capacity reductions are introduced. The proposed method has been successfully applied to derive capacity reductions using operational data. The results obtained are encouraging. It is believed that the method could be implemented in many traffic control centres to improve capacity reduction estimations

Traffic operations from open to dedicated e-Lane

This paper describes the investigation of traffic operations on both dedicated and open e-Lanes. The scenario is regarded as a migratory stage towards eventually full automation of urban principal road traffic operation. The traffic operations were investigated using a be-spoke microscopic simulation model. It was found that under certain Dual Mode Vehicle (DMV) demand level and at certain headway policy, the open e-Lane operation can be further improved by migrating to a dedicated e-Lane operation.