Capacity reductions at incidents sites on motorways

Incidents cause a large part of the delays in road networks. This is caused by a decrease of the capacity at the incident site. A detailed knowledge of the queue discharge rate can improve for instance the traffic prediction and thereby improve delay information or routing advice. Therefore, this study determines the queue discharge rate for many incident locations during an incident situation and these are compared with the queue discharge rate at the same location in normal conditions. Ninety incidents meet the requirements to apply the proposed methodology. It is found in case a driving lane is blocked, the queue discharge rate for each available lane is reduced by 50%. In case the driving lanes are open but there is a distraction of an incident at the emergency lane or on the roadway for the opposite direction, the queue discharge rate is reduced by 30%.