Baher Abdulhai

Enhancing the universality and transferability of freeway incident detection using a Bayesian-based neural network

Development of a universal freeway incident detection algorithm is a task that remains unfulfilled despite the promising approaches that have been recently explored. Incident detection researchers are realizing that an operationally successful detection framework needs to fulfill a full set of recognized needs. In this paper we attempt to define one possible set of universality requirements. Among the set of requirements, a freeway incident detection algorithm needs to be operationally accurate and transferable. Guided by the envisioned requirements, we introduce a new algorithm with potential for enhanced performance. The algorithm is a modified form of the Bayesian-based Probabilistic Neural Network (PNN) that utilizes the concept of statistical distance. The paper is divided into three main sections. The first section is a detailed definition of the attributes and capabilities that a potentially universal freeway incident detection framework should possess. The second section discusses the training and testing of the PNN. In the third section, we evaluate the PNN relative to the universality template previously defined. In addition to a large set of simulated incidents, we utilize a fairly large real incident databases from the I-880 freeway in California and the I-35W in Minnesota to comparatively evaluate the performance and transferability of different algorithms, including the PNN. Experimental results indicate that the new PNN-based algorithm is competitive with the Multi Layer Feed Forward (MLF) architecture, which was found in previous studies to yield superior incident detection performance, while being significantly faster to train. In addition, results also point to the possibility of utilizing the real-time learning capability of this new architecture to produce a transferable incident detection algorithm without the need for explicit off-line retraining in the new site. In this respect, and unlike existing algorithms, the PNN has been found to markedly improve in performance with time in service as it retrains itself on captured incident data, verified by the Traffic Management Center (TMC) operator. Moreover, the overall PNN-based framework promises potential enhancements towards the envisioned universality requirements.

Multiagent Reinforcement Learning for Integrated Network of Adaptive Traffic Signal Controllers (MARLIN-ATSC): Methodology and Large-Scale Application on Downtown Toronto

Population is steadily increasing worldwide, resulting in intractable traffic congestion in dense urban areas. Adaptive traffic signal control (ATSC) has shown strong potential to effectively alleviate urban traffic congestion by adjusting signal timing plans in real time in response to traffic fluctuations to achieve desirable objectives (e.g., minimize delay). Efficient and robust ATSC can be designed using a multiagent reinforcement learning (MARL) approach in which each controller (agent) is responsible for the control of traffic lights around a single traffic junction. Applying MARL approaches to the ATSC problem is associated with a few challenges as agents typically react to changes in the environment at the individual level, but the overall behavior of all agents may not be optimal. This paper presents the development and evaluation of a novel system of multiagent reinforcement learning for integrated network of adaptive traffic signal controllers (MARLIN-ATSC). MARLIN-ATSC offers two possible modes: 1) independent mode, where each intersection controller works independently of other agents; and 2) integrated mode, where each controller coordinates signal control actions with neighboring intersections. MARLIN-ATSC is tested on a large-scale simulated network of 59 intersections in the lower downtown core of the City of Toronto, ON, Canada, for the morning rush hour. The results show unprecedented reduction in the average intersection delay ranging from 27% in mode 1 to 39% in mode 2 at the network level and travel-time savings of 15% in mode 1 and 26% in mode 2, along the busiest routes in Downtown Toronto.

GENETIC ALGORITHM-BASED OPTIMIZATION APPROACH AND GENERIC TOOL FOR CALIBRATING TRAFFIC MICROSCOPIC SIMULATION PARAMETERS

GENOSIM is a generic traffic microsimulation parameter optimization tool that uses genetic algorithms and was implemented in the Port Area network in downtown Toronto, Canada. GENOSIM was developed as a pilot software as part of the pursuit of a fast, systematic, and robust calibration process. It employs the state of the art in combinatorial parametric optimization to automate the tedious task of hand calibrating traffic microsimulation models. The employed global search technique, genetic algorithms, can be integrated with any dynamic traffic microscopic simulation tool. In this research, Paramics, the microscopic traffic simulation platform currently adopted at the University of Toronto Intelligent Transportation Systems Centre, was used. Paramics consists of high-performance, cross-linked traffic models that have multiple user adjustable parameters. Genetic algorithms in GENOSIM manipulate the values of those control parameters and search for an optimal set of values that minimize the discrepancy between simulation output and real field data. Results obtained by replicating observed vehicle counts are promising.

Forecasting of short-term traffic-flow based on improved neurofuzzy models via emotional temporal difference learning algorithm

Bounded rationally idea, rather that optimization idea, have result and better performance in decision making theory. Bounded rationality is the idea in decision making, rationality of individuals is limited by the information they have, the cognitive limitations of their minds, and the finite amount of time they have to make decisions. The emotional theory is an important topic presented in this field. The new methods in the direction of purposeful forecasting issues, which are based on cognitive limitations, are presented in this study. The presented algorithms in this study are emphasizes to rectify the learning the peak points, to increase the forecasting accuracy, to decrease the computational time and comply the multi-object forecasting in the algorithms. The structure of the proposed algorithms is based on approximation of its current estimate according to previously learned estimates. The short term traffic flow forecasting is a real benchmark that has been studied in this area. Traffic flow is a good measure of traffic activity. The time-series data used for fitting the proposed models are obtained from a two lane street I-494 in Minnesota City, USA. The research discuss the strong points of new method based on neurofuzzy and limbic system structure such as Locally Linear Neurofuzzy network (LLNF) and Brain Emotional Learning Based Intelligent Controller (BELBIC) models against classical and other intelligent methods such as Radial Basis Function (RBF), Takagi-Sugeno (T-S) neurofuzzy, and Multi-Layer Perceptron (MLP), and the effect of noise on the performance of the models is also considered. Finally, findings confirmed the significance of structural brain modeling beyond the classical artificial neural networks.

Emergency evacuation planning as a network design problem: a critical review

Abstract Planning for emergency evacuation has evolved and matured substantially during the last two decades. The significant rise in natural and man-made disasters in recent years created a surge in the need for improved emergency evacuation planning. Voluminous studies, formulations, and control approaches have been presented in the literature with the common goal of improving the evacuation process to save precious time and lives. Proposed methods for improving the efficiency of emergency evacuation include reversing lanes in the direction of evacuation (contra-flow), staging the evacuation process, optimally controlling traffic, and providing route guidance to the evacuees. The objective of this paper is to review and compile the main strategies and approaches of emergency evacuation planning. Since most of these strategies can be generally viewed as a network design problem, particular attention has been given to briefly reviewing the network design problem (NDP) and the mutual mapping to the evacuation planning problem. In addition, this review touches upon the role of simulation in replicating the transportation network and the optimization in solving the evacuation problem. As we summarize the common schools of thought in evacuation planning, we critique the limitations, gaps, and challenges that hinder the development of an integrated optimal evacuation planning model. We also propose a framework that compiles evacuation strategies, network design problem formulation, traffic simulation and optimization tools in an attempt to fill some of the identified gaps/limitations.

Managing Large-Scale Multimodal Emergency Evacuations

This article presents the development of a novel framework that optimizes the evacuation of large cities using multiple modes including vehicular traffic, rapid transit, and mass-transit shuttle buses. A large-scale evacuation model is developed for the evacuation of the City of Toronto in case of emergency. A demand estimation model is first designed to accurately quantify the evacuation demand by mode (drivers vs. transit users), over time of the day when the crisis begins, and over space (location). The output of the demand estimation model is then fed into two optimization platforms: (1) an optimal spatio-temporal evacuation (OSTE) model that synergizes evacuation scheduling, route choice, and destination choice for vehicular traffic and (2) a model based on a new variant of the vehicle routing problem to optimize the routing and scheduling of mass-transit vehicles. The study concluded that OSTE can clear the City of Toronto 4 times faster than the do-nothing strategy. The OSTE average automobile evacuation time for the 1.21 million people using their cars is close to 2 h. The optimization of the routing and scheduling of the readily available Toronto Transit Commission fleet (4 Rapid Transit lines and 1320 transit buses used as shuttles) can efficiently evacuate the transit-dependent population (1.34 million) within 2 h.

Fusing a Bluetooth Traffic Monitoring System With Loop Detector Data for Improved Freeway Traffic Speed Estimation

Anonymous probe vehicle monitoring systems are being developed to measure travel times on highways and arterials based on wireless signals available from technologies such as Bluetooth. Probe vehicle data can provide accurate measurements of current traffic speeds and travel times due to their excellent spatial coverage. However, presently probe vehicles are only a small portion of the vehicles that make up all of the traffic in the network. Alternatively, data from conventional loop detectors cover almost all the vehicles that have traveled along a road section, resulting in excellent temporal coverage. Unfortunately, loop detector measurements can be imprecise; their spatial sampling depends on the loop detector spacing, and they typically only represent traffic speed at the location of the detector and not over the entire road segment. With this complementarity in mind, this article explores several data fusion techniques for fusing data from these sources together. All methods are implemented and compared in terms of their ability to fuse data from loop detectors and probe vehicles to accurately estimate freeway traffic speeds. Data from a Bluetooth traffic monitoring system are fused with corresponding loop detector data and compared against GPS collected probe vehicle data on a stretch of Highway 401 in Toronto, Canada. The analysis shows that through data fusion, even a few probe vehicle measurements from a Bluetooth traffic monitoring system can improve the accuracy of traffic speed estimates traditionally obtained from loop detectors.

Real-Time Optimization for Adaptive Traffic Signal Control Using Genetic Algorithms

Control methodologies of traffic signals have significantly improved during the recent past along with advancements in technology. Adaptive traffic signal control is the most recent and advanced control type of traffic signals. Adaptive control is able to efficiently relieve traffic congestion by continuously adjusting signal timings according to real-time traffic conditions. Conventional optimization methods such as integer programming, hill climbing, or descent gradient searching have been gradually overshadowed by genetic algorithms in many areas including traffic signal operation. The research presented in this article is distinct from previous studies in that it focuses on real-time adaptive signal optimization using genetic algorithms. The proposed adaptive signal system provides acyclic signal operation based on a rolling horizon real-time control approach. The algorithm was tested using microsimulation for on-line evaluation and comparison to fixed-time plans generated from the latest TRANSYT-7F version 9.7, which has a genetic optimization feature. The developed signal system consists of three major components including a genetic algorithm optimization module, an internal traffic simulation module, and a database management system all working in cooperation to optimize signal timings in real time. Using the pseudo on-line simulation platform, three testing scenarios for high, medium, and low level of traffic demands were conducted focusing on evaluating several important features of the proposed adaptive signal control system. The test results indicated that real-time genetic control outperformed fixed-signal timing plan in all scenarios based on total vehicle delay.

Multiobjective Optimization for Multimodal Evacuation

This paper proposes a multimodal optimization framework that combines vehicular traffic and mass transit for emergency evacuation. The multi-objective approach optimizes the multimodal evacuation framework by investigating three objectives: minimizing in-vehicle travel time, minimizing at-origin waiting time, and minimizing fleet cost in the case of mass transit evacuation. For auto evacuees, an optimal spatiotemporal evacuation (OSTE) formulation is presented for generating optimal demand scheduling, destination choice, and route choice simultaneously. OSTE implements dynamic traffic assignment techniques coupled with genetic optimization to achieve the objective functions. For transit vehicles, a multiple-depot, time-constrained, pickup and delivery vehicle routing problem (MDTCPD-VRP) is formulated to model the use of public transit shuttle buses during evacuation. MDTCPD-VRP implements constraint programming and local search techniques to achieve the objective function and satisfy constraints. The OSTE and MDTCPD-VRP platforms are integrated in one framework to replicate the impact of congestion caused by traffic on transit vehicle travel times. This paper presents a prototype implementation of the conceptual framework for a hypothetical medium-size network in downtown Toronto, Ontario, Canada. The results show that including the waiting time and the in-vehicle travel time in the objective function reduced the network clearance time for auto-evacuees by 40% compared with including only the in-vehicle travel time. For mass transit, when considering fleet cost, an increase of 13% in network clearance time for transit evacuees was observed with a decrease of 12% in fleet size. Mass transit was shown to provide latent transportation capacity that is needed in evacuation situations.

SPATIO-TEMPORAL INDUCTANCE-PATTERN RECOGNITION FOR VEHICLE RE-IDENTIFICATION

Abstract Very recent research efforts started investigating the possibilities of more ‘intelligent’ usage of Inductive Loop Detectors (ILD), to possibly derive ‘wide-area’/‘section-related’ measures from their outputs, as opposed to the limited conventional point measurements. This research attempts to improve the accuracy of vehicle re-identification at successive loop detector stations through improving the distance measures for pattern nearness in the pattern matching process. Vehicle inductance-signature data, collected by a California team of researchers, were further analysed at the University of Toronto. Several new techniques including neural networks, new distance measures and waveform warping-reduction processes were investigated to match the vehicle signature waveforms showing potential for significant accuracy improvement compared to features reported in the literature.