International Journal for ITS Research

 

Research

Urban network travel time estimation

Most of the research on travel time estimationis limited to freeways. However, on the urban networks, presence of signalised and non-signalised intersections; loss or gain of vehicles due to parking etc makes the problem more challenging.

The model is based on the principle that the area between the cumulative plots at the entrance and exit of the link defines its total travel time. Analytical modelling is performed to accurately estimate cumulative plots based on the availability of the data. The accuracy of the estimation is enhanced by data fusion with probe vehicle.

The model can be applied for Performance evaluation of the system and Level of Service of different intersections. The performance of the system provides feedback to the signal controller to optimise its parameters. The model is also applicable to:
• Advanced Traveller Information Systems;
• Dynamic route guidance; and
• Public Transport Priority System.

 

Improved method for dynamic OD estimation

Most OD matrices used for traffic operation studies are adapted from OD estimated for transport planning. As the resolution demanded of a transport planning model is less rigorous, the use of this OD matrix for dynamic traffic assignment in micro simulation may not be appropriate. Instead of adjusting static ODs using Wardrop’s user equilibrium, this research uses micro simulation to achieve a dynamic equilibrium which will be the basis for time dependent OD estimation. Challenges in this research include calibration of the simulation model and adjustment of OD matrices to ensure convergence of the methodology. The result of this research will be an integrated approach to estimate dynamic OD matrices suitable for transport planning and traffic operations.

 

FUSAIN (FUsion of SAfety INdicators)

FUSAIN is a research project supported by the Swiss FEDeral Road Office (FEDRO). With the rapid deployment of Intelligence Transportation Systems (ITS), real-time characterisation and prediction of network state play a key role in various ITS applications, such as Advanced Traffic Management Systems (ATMS), Dynamic Vehicle Navigation Systems (DVNS) and Advanced Travel Information Systems (ATIS). This real-time characterisation is quite well addressed from traffic perspective, with a variety of performance indicators. However, there is a huge need for real-time, reliable and effective indicators to assess traffic situation from a safety perspective. This is precisely the target of FUSAIN. Moreover, the big influence of the meteorology on traffic conditions and in particular traffic safety, makes the study of the meteorological data particularly important and interesting for FUSAIN. One of the innovative aspects of this project is to use the meteorological sensors, which are at present used only for the winter maintenance (salting), to improve the road safety in real time, according to the local meteorology.

The main objectives of FUSAIN within the framework of the safety of the motorway traffic are:
to use, adapt and create safety indicators based on traffic detector data,
to develop a method of combining the indicators to know with confidence - and in   real-time - the state of traffic safety, and
to take into account weather conditions in the safety indicators (fog, wet road,   snows, frost), notably by the effect of these conditions on the road friction,   visibility, etc.

Once FUSAIN has produced its consolidated safety indicator, we will hence study, in the extensions of FUSAIN, the effect of different regulation measures on traffic performance and safety. The final goal is to help manage the motorway traffic not only in term of traffic performance - as done currently -, but also in term of safety, notably by disseminating information or regulation measures to the users in order to reduce the risk of accident and mitigate the effects of accidents.