Prediction of reliability of travel time using a transport forecast model. Nowadays it is not easy anymore to predict the time use of a trip. The amount of trip kilometres has grown relatively faster than the length of the infrastructure, the utilization of the network has therefore risen. The outcome is a smaller capacity reserve for reducing the effects of incidents : as a result, larger delays and more congestion are expected. The reliability of predicted travel times has decreased quickly, whereas the importance of reliability for travellers is great. In a ‘normal’ transport forecast model it is not straightforward to estimate the variability of travel times because of the vast amount of situations that can cause unreliability (accidents and road work can occur on each existing road track). The input and calculation of this high number of situations is in most cases too time-consuming. The SMARA model (Strategic Model for Analyzing the Reliability of Accessibility) is built on a innovative method in which stochastics in a Monte Carlo simulation result in reliability intervals of travel times. In short, SMARA draws the amount of transport demand, and the capacity of transport supply, making use of adjustable distribution functions. The changed supply and demand have effect on the door-to-door travel times. By executing this method a number of times, reliability intervals can be derived. (Author/publisher)
Abstract