http://www.ifac-papersonline.net/ en Copyright 09:10 AM Saturday 18, 2013 IFAC-PapersOnline http://www.ifacpapersonline.com 09:10 AM Saturday 18, 2013 09:10 AM Saturday 18, 2013 ET webmaster@ifac-papersonline.net webmaster@ifac-papersonline.net http://www.ifac-papersonline.net/Detailed/30951.html 04:00 PM Wednesday 31, 1969 http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30952.html 04:00 PM Wednesday 31, 1969 Vehicle intelligence has been advocated as a potential way of improving safety, driver comfort, traffic flow characteristics and efficiency in general. Despite considerable research efforts in vehicle technologies, vehicles continue to be treated as passive users of the traffic network while highway traffic operates as an open loop dynamical system most of the time. The purpose of this paper is to present and analyse vehicle technologies which could help close the loop with the highway system. Vehicle to road communication would allow vehicles to act as sensors and actuators by having the vehicles communicate to the roadway their speed, location, origin/destination and status and respond to the roadway by obeying speed limits and ramp metering lights. This communication technology together with a traffic management and control system could lead to a new generation of highway system which could be effectively controlled to operate as close to capacity as possible. In this paper we describe the structure of the proposed controlled highway system and present some preliminary results. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30953.html 04:00 PM Wednesday 31, 1969 With Beijing's successful winning of its bidding for the 2008 Olympic Games, Beijing is striving to become a modern international metropolis and builds a NEW BEIJING TRANSPORT SYSTEM for the Games. The paper introduces the characteristics of the Olympic transport and urban transport objectives, and develops a strategy for the Games. Citizen in Beijing know that the Olympic Games are a great opportunity, to accelerate the development of Beijing transport system, to improve the traffic consciousness, to establish a "user service" idea in the minds of transport managers, and to provide wonderful systematic travel services in order to hold unique and successful Olympic Games. Beijing now makes great efforts to grasp this opportunity. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30954.html 04:00 PM Wednesday 31, 1969 Large events impose additional loads on the transport system. Regular and surplus event based traffic is modelled in order to improve traffic operations during arrival and departure of the visitors. This paper presents three modelling approaches applied in Germany over recent years. in Hanover. First micro simulation is applied to evaluate access to parking facilities to the Allianz-Arena in Munich. Second a mesoscopic model has been used at the EXPO2000 in Hanover to forecast travel times and third a macroscopic traffic model supplemented by a new propagation algorithm is being used in Berlin for multiple purposes including traffic flow estimation during the FIFA championship. All examples contain simultaneous modelling of various traffic control measures. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30955.html 04:00 PM Wednesday 31, 1969 Presented is a real-world testbed for Automatic Incident Detection (AID) systems that consists of an online data warehouse storing a month of traffic video, the corresponding traffic data and an operator log of incident start/end times. A proof-of-concept field evaluation is conducted whereby the testbed is used to calibrate, and then analyze the performance of four AID systems: California Algorithm 8, McMaster Algorithm, GAID Algorithm, and Citlog-VisioPAD. The pilot evaluation shows considerable advantages of the testbed in its ability to analyse the performance of the AID systems. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30956.html 04:00 PM Wednesday 31, 1969 This paper addresses the problem of freeway traffic flow estimation. The freeway is considered as a network of components representing different freeway stretches called segments. The evolution of the traffic in a segment is modelled as a dynamic stochastic system, influenced by states of neighbour segments. Measurements are received only at boundaries between some segments and averaged within regular time intervals. An Unscented Kalman filter is developed and its performance is compared with a particle filter both for synthetic data and for real traffic data. The intended application is to supply traffic control systems with the estimated traffic state. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30957.html 04:00 PM Wednesday 31, 1969 For effective (network) traffic control, such as route guidance, one of the key requirements is to derive an estimate of the current state in the traffic network. A principle method of doing so, is to combine a traffic network model with available measurement data by means of an Extended Kalman filter (EKF). One of the virtues of using an EKF is that aside from an estimate of the mean traffic state on each link also an estimate of the state estimation error covariance matrix is obtained, which reflects the uncertainty in the state estimates. This paper describes how this can be done analytically in the case of a first order traffic flow model and discusses some preliminary results. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30958.html 04:00 PM Wednesday 31, 1969 This paper presents the evaluation of the incident information transmission on highways from a vehicle that detects or encounters an incident to following vehicles over the inter-vehicle communications by relaying the information. The transmission is evaluated with the transmission range with the communication unit penetration rate. The evaluation is conducted with simulation studies based on the Monte Carlo method as well as an analytical approach. The results show that the penetration rate for a feasible incident information transmission system is at least 10 % to 20 % depending on the traffic volume. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30959.html 04:00 PM Wednesday 31, 1969 The Dutch national road authority Rijkswaterstaat is responsible for effective incident management. To this end Rijkswaterstaat continuously searches for detection schemes that allow the robust, timely and because of cost constraints preferably automated detection of incidents. The quality of such algorithms is measured against the dimensions of detection rate, false alarm rate and response time. For that purpose, we investigated in what way the currently available loop detector data of traffic speed and flow can be used to detect incidents. Faster and more accurate incident detection is the first step in making the process of incident management more efficient. In this paper, we present a comparison of an earlier presented Dutch algorithm with a number of different algorithms. These algorithms were specifically developed for this study, with the aim to improve the current possibilities of detecting incidents. It appears that one algorithm offers improvements over our original algorithm, and that another algorithm offers the potential of improvements. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30960.html 04:00 PM Wednesday 31, 1969 Speed-density relationships are a classic way of modeling stationary traffic relationships. Besides offering valuable insight in traffic stream flows, such relationships are widely used in simulation-based Dynamic Traffic Assignment (DTA) systems. In this paper, alternative approaches for modeling traffic dynamics, appropriate for traffic simulation, are proposed. Their basic premise is the wide availability of sensor data. The approaches are based on machine learning methods such as locally weighted regression and support vector regression. Neural networks are also considered, as they are a well-established approach, successful in many applications. While such models may not provide as much insight into traffic flow theory, they allow for easy incorporation of additional information to speed estimation, and hence, may be more appropriate for use in DTA models, especially simulation based. In particular, in this paper, it is demonstrated (using data from a network in Irvine, CA) that the use of such machine learning methods can improve the accuracy of speed estimation. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30961.html 04:00 PM Wednesday 31, 1969 The offset control module of the TUC strategy for urban traffic control strategy is replaced by a bandwidth maximisation module. Bandwidth maximisation is performed online based on split and cycle changes. Simulations of a five junction arterial were carried out with results indicating that performance is comparable to optimally adjusted fixed-time plans. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30962.html 04:00 PM Wednesday 31, 1969 Progression systems synchronize traffic signals to maximize the green band, so that vehicles entering the band at one end of the arterial can pass the other unimpeded. Although traffic control systems optimize other criteria, such as travel time and traffic flow, synchronization remains a desirable feature as drivers are averse to frequent stops. This paper gives a short account of progression systems based on bandwidth maximization, including MAXBAND and MULTIBAND, which can be cast as mixed-integer linear programming problems. To this end, the paper offers a brief review of cutting-planes, before developing a Chvátal-Gomory-based cutting-plane algorithm for bandwidth maximization and reporting numerical results. The cutting planes proved to be effective in the first iterations, inducing a substantial reduction on the upper bound for the maximum green band, but became ineffective in the remaining iterations. This paper finalizes with a research agenda to develop fast, effective algorithms for real-time applications. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30963.html 04:00 PM Wednesday 31, 1969 The coordination of signal controls in a traffic network has a significant impact on throughput and journey times. Traditionally, signal coordination is optimized as a separate model step, after route flows have been obtained from an assignment. A better integration of both steps requires a model of signal coordination which admits a fast solution method. We describe such a model and a solution based on mathematical optimization techniques for mixed-integer problems. Compared to existing approaches, our method supports non-uniform cycle lengths and yields optimal solutions (w.r.t. the objective function of our model) in less computation time. We use microsimulation to compare the resulting signal phasing to one obtained from an industry standard model and report on effectiveness and computational effort. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30964.html 04:00 PM Wednesday 31, 1969 This paper studies a control of traffic flow dynamics in urban road networks. The signal control system of the congestion length is described by a nonlinear time-varying discrete dynamic system and synthesized by using the hierarchical control. A signal control algorithm in which the three signal control parameters consisting of the cycle length, green split and offset are searched systematically so as to minimize the sum of congestion lengths in the urban road network is presented. The dynamic route guidance system is consisted of both the evaluation for the mean OD travel time and the route search algorithm. The traffic flow control system, which is most effective to reduce the congestion lengths in urban road networks, is designed by connecting the signal control system with the dynamic route guidance system in real time. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30965.html 04:00 PM Wednesday 31, 1969 The problem of optimal traffic coordination in rectangular street networks is presented in the paper. The problem description was simplified as much as possible, by defining minimal set of decision variables and deriving necessary constraints on their values. The properties of optimal solution for quadratic goal function were established and the optimal solution has been derived analytically for mutual vehicle group positions. The optimal undisturbed coordination is compared with node capacity constrains in fuzzy form to find a degree of fulfilment of capacity constrains in street network. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30966.html 04:00 PM Wednesday 31, 1969 Present air traffic demand expected growth assume that current airport services levels must increase in the same percentage in order to avoid congestion problems. SPADE is a distributed computer system which integrate different specific commonly used tools that supply a simple workflow to answer some questions to help airport planners and operators in the decision making process. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30967.html 04:00 PM Wednesday 31, 1969 Air traffic flow management in Europe has to deal with capacity constraints in en route airspace, in addition to the usual capacity constraints at airports. The enroute sector capacity constraints, in turn, generate complex interactions among traffic flows. A new deterministic mathematical model for the European ATFM problem is presented. The model designs flow management strategies involving combinations of ground and airborne holding. The paper illustrates the complex nature of EU ATFM solutions, the benefits that can be obtained by assigning some airborne holding delays in addition to ground delays, and the issues of equity that arise in the EU ATFM context as a result of the interactions among traffic flows. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30968.html 04:00 PM Wednesday 31, 1969 In this work, both univariate and multivariate air transport demand ARIMA models are proposed to estimate the demand levels about Reggio Calabria regional airport (South of Italy), in order to make available a tool able to analyse the impact of recent modifications in the supply (new links, new destinations and lower fares) that are expected to produce an increase in the air transport demand, also due to induced trips generated by the new supply. Differences between the univariate and multivariate models are highlighted. The models calibrations have been obtained by using the Box-Jenkins procedure. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30969.html 04:00 PM Wednesday 31, 1969 Weather is one of the most impacting sources of delay in terms of air traffic. Many applications have shown that the use of weather forecast enables the airport controllers to improve the efficiency and the safety of an airport. To date, it is still challenging to analyse a set of weather factors to predict the airport's capacity or the travel time of single aircraft. Mostly, this is due to the high complexity of the data. In this paper the results of an application that visualises complex weather data and its impact on air traffic are shown. Support Vector Regression (SVR) is then applied to demonstrate the prediction of aircraft flight duration by means of a modern nonlinear statistical technique. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30970.html 04:00 PM Wednesday 31, 1969 The critical density of a freeway link is subject to changes over time owing to such circumstances as environmental conditions (snow, rain, etc.) and traffic incidents. The critical density affects the performance of some ramp metering strategies that make use of it as a threshold value for control action; therefore, it is imperative to trace the real value of the critical density. The focus of this paper is to evaluate the effects of the novel online critical density estimation methods proposed by Ozbay et al. (2006) on the performance of the two new feedback-based coordinated ramp metering strategies, namely C-MIXCROS and D-MIXCROS (Kachroo and Ozbay 2003), which explicitly consider ramp queues using microscopic simulation models on an 11-mile corridor of I- 295 in South Jersey under various demand conditions. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30971.html 04:00 PM Wednesday 31, 1969 The ACCEZZ ramp metering algorithm is an adaptive control approach based on Fuzzy Logic. Results from its calibration and validation as well as its evaluation using a microscopic simulation show how different control strategies can improve traffic conditions especially during peak hours. To evaluate the potential of ramp metering the ramp metering software TRANSRAMP has been developed, implemented and tested at a demonstration site in Munich (Germany). Since December 1st, 2005 TRANSRAMP controls traffic at two consecutive on ramps successfully with the ACCEZZ algorithm. Data for a cross-algorithm (with ALINEA) and a cross-site evaluation will be collected until April 2006 within the European research project EURAMP. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30972.html 04:00 PM Wednesday 31, 1969 A nonlinear rolling-horizon model-predictive hierarchical coordinated ramp metering scheme is presented. The hierarchical control structure consists of three layers: the estimation/prediction layer, the optimization layer and the direct control layer. The second layer incorporates the previously designed optimal control tool AMOC while the local feedback strategy ALINEA is used in the third layer. Simulation results are presented for the Amsterdam ring-road. It is shown that control of all on-ramps including freeway intersections leads to the optimal utilization of the available infrastructure. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30973.html 04:00 PM Wednesday 31, 1969 To control the traffic flows near on-ramps and off-ramps, ramp metering installations can be used. We compare on-ramp metering and off-ramp metering, with respect to queue forming and total time spent. Both control measures are used to improve traffic flow on freeways, and both have influence on the route choice of the drivers. Although the two measures are very similar, there are some major differences. The use of ramp metering installations can change the traffic assignment in the network because the inflows or outflows of the freeways are limited. This will result in a change in travel times in the network. And since drivers make a route choice based on these travel times, the route choice (and thus the traffic assignment) can change as well. This can lead to a relocation of queues in the network. With a case study we illustrate the differences between on-ramp and off-ramp metering, with three different control methods: fixed time control, ALINEA and a model predictive control-based method. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30974.html 04:00 PM Wednesday 31, 1969 During morning peak hours highway A12 is highly congested. Traffic from surrounding towns is concentrated on highway A12 towards the city of Arnhem. In order to optimise the traffic flow on highway A12 and on the neighbouring secondary roads a network control system has been developed and tested in the microscopic simulation model VISSIM. Using a real time decision model the amount of traffic entering highway A12 is continuouslys and automatically increased or decreased using the existing traffic controls near the on-ramps. Simulation results show a 25% decrease of travel time and a reduction of total delay time of 200 hours (-16%). http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/30975.html 04:00 PM Wednesday 31, 1969 This article deals with the establishment of a new real-time routing strategy for road traffic networks. On the basis of the Lighthill-Whitham-Richards single order model, a "system-optimal" strategy is developed and validated with numerical simulations. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif