The basic aim of this project is to identify the effect of RTI measures on the existing relationships between speed flow and capacity on interurban roads.
Conversely, the effects of traffic flow and behavioural conditions on the performance of RTI systems will be considered.
Work has been concerned with the development and use of a series of calibrated microscopic simulation models to investigate the potential range of road transport informatics (RTI) measures to provide improvements in efficiency, safety and economy on interurban highways.
The 3 main devices investigated in the simulation models have been:
headway advice and control systems, acting on vehicle to vehicle following relationships (the headway element governs the longitudinal distance or time spacing between vehicles, by giving advice on following distances);
speed advice and control systems;
lane changing aids on multilaned roads and overtaking aids on 2-lane, 2-way roads (these attempt to influence the lateral movements of vehicles and seek to aid both safety and capacity by achieving a more optimal flow and desired speed).
After a review of empirical studies and existing microscopic simulation models, as well as of RTI technologies, the most appropriate modelling techniques will be determined for the project.
It is anticipated to use two simulation models out of 3 available currently by partners of the consortium, and modify and develop them appropriately in order to fulfil the basic aims of the project, i.e. to represent traffic-flow-capacity relationships on a wide range of interurban road conditions (from 2- lane single carriageway roads to multi-lane motorways) and assess the effects of the introduction of RTI facilities on them.
The 2 models will be validated - calibrated on field data representing a wide range of European conditions, by taking measurements in 4 countries, i.e. Germany, U.K., Greece and Norway and using various modern data collecting techniques (e.g. video techniques, aerial observations, etc...)
Where, there is a new need emerging, new model elements will be developed accordingly.
If measurements of traffic flow and associated parameters are available from other Projects these data will be used to validate the RTI elements within the simulation models.
Subsequently the 2 models, after their calibration, will be used to run an extensive series of simulation runs covering various road, traffic and environmental conditions.
These runs will be repeated with and without superimposition of the RTI technology, so that the effects of RTI systems on speed-flow-capacity relationships will be determined under various conditions.
The driver's behavioural response to RTI aids will be assessed through a series of additional sensitivity tests.
The results on all the above simulation runs under various conditions will be analysed statistically in order to draw conclusions in a systematic way of the effect of RTI systems' introduction on fundamental traffic relationships.
Finally, an attempt will be made to analyse and evaluate the implications of RTI systems at the inter-urban/urban interface, and to explore the links which should connect inter-urban and urban RTI systems.
Reports on finalisation of models, completion of simulations and estimation of RTI effects, recommendations.