Evaluation of the impact on capacity at incidents
In order to achieve the best possible traffic management during incidents, effective decision support is needed for the traffic management centers. The safety at the incident site for both road users and rescue units is of course the first priority. However, the choice of traffic management strategy and the timing for the incidents also affect capacity and traffic efficiency. Today, it is difficult to estimate the effects of an intended traffic management strategy as knowledge of how different types of incidents and traffic management strategies affect capacity and accessibility is limited.
One problem in analyzing the effects on traffic efficiency and capacity of incidents is that information about how many lanes an incident blocks or how many lanes that are closed by the traffic management center is not saved (alternatively not saved with sufficient detail level). Furthermore, information is not saved on how long time lanes are blocked or closed, time from the report of the incident to the arrival of rescue leaders, rescue vehicles, time required for partial progress in incident management (such as medical care, rescue, etc.). All this information is essential in the development of incident support decision-making to ensure that the best traffic management strategies are used. Collection of this type of information needs to be done through automatic logging or with the help of outside observers as traffic managers, roadside assistance and rescue personnel need to have full focus on handling the incident.
Better knowledge of the impact of incidents on capacity and traffic efficiency is also an important for prediction of travel times. To ensure the best possible travel time forecasts during incidents, knowledge is needed on how the incident and the planned traffic management strategy will affect the capacity at the incident site. Most travel time forecasts are based on measurements of the current situation which, together with a traffic model, are used to estimate how travel times will change. Knowledge of planned traffic management strategies and their effect on capacity is thus essential for correct prediction.
In this project the aim is to propose empirically well-founded relationships between different types of incidents, capacity and traffic efficiency for motorways. The project results should be applicable in traffic flow models for impact assessment of incidents and for travel time prediction during incidents. The existing data sources the proposed methodology is illustrated in Figure 1.
The project is carried out by VTI and LiU and is funded by Trafikverket via Centre for Traffic Research (CTR).
