The Influence of Spillback Modelling when Assessing Consequences of Blockings in a Road Network

Robustness of a network is a main objective for road network managers these days, and has therefore become an important study area for transportation scientists. This article discusses one specific aspect in assessing road network robustness: the consequences of the closure of a link. These spillback effects have been examined in a dedicated traffic simulator in which the representation of spillback can be switched on and off. The impacts are studied in a simulation study of a road network of a regional size in which sequentially links are blocked. Two scenarios for route choice are considered: a fixed route choice based on a daily congestion pattern and a route choice adapted to the actual congestion caused by the closure. The study has also shown the influence of information which makes travellers adapt their routes. Road network robustness and characteristics of vulnerable links are evaluated for both spillback and non-spillback cases. It is found that a valid spillback modelling is a prerequisite for correctly analysing the robustness of the network as a whole, as well as for correctly indicating the locations in the network where a closure causes the largest delays. Furthermore, without simulating spillback, it is not possible to identify correctly the most vulnerable links for the network performance

Optimal Redesign of the Dutch Road Network

The Dutch national road network has been developed over several decades. In the past, roads were constructed according to the then current spatial and transportation planning philosophies. Because the existing road network is a result of a long process of successive developments, the question can be asked whether this network is the most appropriate from the current point of view, especially taking in consideration the current socio economic structure of the Netherlands. To answer this question an optimization algorithm for designing road networks has been developed. With this algorithm the Dutch road network has been redesigned based on minimization of the travel and infrastructure costs and by taking into account the socio economic structure of the Netherlands. A comparison between the existing network and the new design shows that the redesigned Dutch national road network has significantly lower total costs than the existing road network. It is found that the construction of less roads with more lanes on different locations leads to a reduction of the total travel time and the total vehicles kilometers traveled

Advanced OR and AI Methods in Transportation PATH SEARCHING AND FILTERING FOR NETWORK SIMULATION TOOLS AIMED AT ROBUSTNESS ANALYSIS

Abstract. Traffic simulation models dealing with road networks are already available for several years. Most of them include procedures to distribute traffic over alternative routes between an origin and destination. However, most of these tools are not capable to include ADAS and route guidance systems realistically. In addition, the interest in the design of reliable and robust networks is growing, while a tool to analyze and quantify these properties is still missing. One important element in such a tool would be the realistic distribution of traffic over logical paths, and the availability of dissimilar alternative paths in case of emergencies. An overview and a new approach are presented in this paper. 1

Learning from a Failed Innovation Process: Personal Rapid Transit for a Dutch City

The technological and institutional innovation process in public transport is slow and difficult to control. Because many forces work on this process, predicting its outcomes is difficult. This was demonstrated in a project in Eindhoven, the Netherlands, where a pilot was prepared to demonstrate the potential of personal rapid transit. The pilot was part of an innovation process to lead to a more sustainable urban transport system. The guidelines of the bureau for sustainable technological development were followed to guarantee the long-term feasibility and effectiveness of the process. Although the process was designed carefully with concern for the predictable risks, the pilot had to be stopped because of unforeseen political problems. A change of policy priorities and key people caused the project’s failure. In addition, strict regulations for tendering bids slowed the process and favored bidders without project knowledge. This paper analyzes the different risk factors and gives conclusions for improving chances for success in future similar innovation projects. Checklists provide a tool to make an ex ante analysis of an innovation project’s feasibility and to give guidance for optimal conditions for success

Probabilistic models for queues at fixed control signals

The estimation of queues at signalized intersections is a classical problem in transportation engineering and operations research. Nevertheless, a general theory able to explain how queues form and cause delays to the drivers is still missing. Typically, queue dynamics are modelled as deterministic, causal phenomena, and under rather limiting assumptions; however, especially in urban networks, these are far from being deterministic or certain. This paper presents a new probabilistic queuing model that can explain the dynamic and stochastic behaviour of queues at fixed controlled signals. The probabilistic approach allows one to capture the temporal behaviour of queues, and to measure the uncertainty of a queue state prediction by computing the evolution of its probability in time, assumed any temporal distribution of the arrivals. This can be fundamental information in, e.g., travel time estimation, network reliability, design and planning of urban areas, and to estimate complex effects that can be observed in congested networks such as spillback or gridlock. Comparison with microscopic simulation shows very good consistency both under the assumption of stationary and non-stationary arrival distributions.Queuing theory Probability theory and Markov Chains Fixed controls Spillback

Traffic Control and Route Choice: Occurrence of Instabilities

Transport and Plannin