154 research outputs found

    A Testing and Experimenting Environment for Microscopic Traffic Simulation Utilizing Virtual Reality and Augmented Reality

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    Microscopic traffic simulation (MTS) is the emulation of real-world traffic movements in a virtual environment with various traffic entities. Typically, the movements of the vehicles in MTS follow some predefined algorithms, e.g., car-following models, lane changing models, etc. Moreover, existing MTS models only provide a limited capability of two- and/or three-dimensional displays that often restrict the user’s viewpoint to a flat screen. Their downscaled scenes neither provide a realistic representation of the environment nor allow different users to simultaneously experience or interact with the simulation model from different perspectives. These limitations neither allow the traffic engineers to effectively disseminate their ideas to various stakeholders of different backgrounds nor allow the analysts to have realistic data about the vehicle or pedestrian movements. This dissertation intends to alleviate those issues by creating a framework and a prototype for a testing environment where MTS can have inputs from user-controlled vehicles and pedestrians to improve their traffic entity movement algorithms as well as have an immersive M3 (multi-mode, multi-perspective, multi-user) visualization of the simulation using Virtual Reality (VR) and Augmented Reality (AR) technologies. VR environments are created using highly realistic 3D models and environments. With modern game engines and hardware available on the market, these VR applications can provide a highly realistic and immersive experience for a user. Different experiments performed by real users in this study prove that utilizing VR technology for different traffic related experiments generated much more favorable results than the traditional displays. Moreover, using AR technologies for pedestrian studies is a novel approach that allows a user to walk in the real world and the simulation world at a one-to-one scale. This capability opens a whole new avenue of user experiment possibilities. On top of that, the in-environment communication chat system will allow researchers to perform different Advanced Driver Assistance System (ADAS) studies without ever needing to leave the simulation environment. Last but not least, the distributed nature of the framework enables users to participate from different geographic locations with their choice of display device (desktop, smartphone, VR, or AR). The prototype developed for this dissertation is readily available on a test webpage, and a user can easily download the prototype application without needing to install anything. The user also can run the remote MTS server and then connect their client application to the server

    Simulating the Impact of Traffic Calming Strategies

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    This study assessed the impact of traffic calming measures to the speed, travel times and capacity of residential roadways. The study focused on two types of speed tables, speed humps and a raised crosswalk. A moving test vehicle equipped with GPS receivers that allowed calculation of speeds and determination of speed profiles at 1s intervals were used. Multi-regime model was used to provide the best fit using steady state equations; hence the corresponding speed-flow relationships were established for different calming scenarios. It was found that capacities of residential roadway segments due to presence of calming features ranged from 640 to 730 vph. However, the capacity varied with the spacing of the calming features in which spacing speed tables at 1050 ft apart caused a 23% reduction in capacity while 350-ft spacing reduced capacity by 32%. Analysis showed a linear decrease of capacity of approximately 20 vphpl, 37 vphpl and 34 vphpl when 17 ft wide speed tables were spaced at 350 ft, 700 ft, and 1050 ft apart respectively. For speed hump calming features, spacing humps at 350 ft reduced capacity by about 33% while a 700 ft spacing reduced capacity by 30%. The study concludes that speed tables are slightly better than speed humps in terms of preserving the roadway capacity. Also, traffic calming measures significantly reduce the speeds of vehicles, and it is best to keep spacing of 630 ft or less to achieve desirable crossing speeds of less or equal to 15 mph especially in a street with schools nearby. A microscopic simulation model was developed to replicate the driving behavior of traffic on urban road diets roads to analyze the influence of bus stops on traffic flow and safety. The impacts of safety were assessed using surrogate measures of safety (SSAM). The study found that presence of a bus stops for 10, 20 and 30 s dwell times have almost 9.5%, 12%, and 20% effect on traffic speed reductions when 300 veh/hr flow is considered. A comparison of reduction in speed of traffic on an 11 ft wide road lane of a road diet due to curbside stops and bus bays for a mean of 30s with a standard deviation of 5s dwell time case was conducted. Results showed that a bus stop bay with the stated bus dwell time causes an approximate 8% speed reduction to traffic at a flow level of about 1400 vph. Analysis of the trajectories from bust stop locations showed that at 0, 25, 50, 75, 100, 125, 150, and 175 feet from the intersection the number of conflicts is affected by the presence and location of a curbside stop on a segment with a road diet

    Validation of a microsimulation of the port of Dover

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    Modelling and simulating the traffic of heavily used but secure environments such as seaports and airports is of increasing importance. Errors made when simulating these environments can have long standing economic, social and environmental implications. This paper discusses issues and problems that may arise when designing a simulation strategy. Data for the Port is presented, methods for lightweight vehicle assessment that can be used to calibrate and validate simulations are also discussed along with a diagnosis of overcalibration issues. We show that decisions about where the intelligence lies in a system has important repercussions for the reliability of system statistics. Finally, conclusions are drawn about how microsimulations can be moved forward as a robust planning tool for the 21st century

    Development of a micro-simulation model toevaluate shuttle-lane roadwork operations

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    This thesis focuses on the development of a micro-simulation model for urban shuttle-lane roadworks. The aim of this research is to study the effectiveness of shuttle-lane roadworks traffic management controls (i.e. operated by temporary traffic signals) on capacity, delays and safety.SIMSUR (SIMulation of Shuttle-lane Urban Roadworks) micro-simulation model is based on car-following and shuttle-lane rules, considers the various decisions undertaken whenapproaching temporary traffic signals at urban shuttle-lane roadworks (i.e. tailgating, crossingthrough amber or even violating the red light). Data from six different sources were collected(from 23 different sites with over 54 hours of traffic data video recordings). This includes data from visited roadworks sites, Individual Vehicle Data (IVD) from UK motorways anddata from typical signalised junctions.Temporary traffic signals operation modes, including Fixed Time (FT) and Vehicle Actuated (VA) signals, have been integrated within the developed micro-simulation model. Thedeveloped model has been verified, calibrated and validated using real traffic data.Various scenarios were tested using the developed simulation model such as the effect of various parameters on system capacity, delays and safety (i.e. site length, HGVs%,directional split, and drivers’ non-compliance with temporary traffic signals). The resultsrevealed that the maximum shuttle-lane roadworks capacity values which could be achieved(using existing temporary traffic signals settings) for two-way flow are 1,860 and 2,060veh/hr for FT and VA signals, respectively. Regression analysis was also carried out usingdifferent factors and could be used in analytical models to provide a more accurate estimationof system capacity compared to existing equations. Using improved signals settings, capacitycould be increased by about 3.5%. Making the assumption that Microwave Vehicle Detector(MVD) could be simulated within the model, various ranges were tested and the optimumrange was found to be 80m (rather than the existing 40m) which could result in an increase insystem capacity of 4.2%. Using speed reduction (i.e. speed hump) in advance of the stop linecould reduce the effect of dilemma zone by reducing the number of vehicles crossing at theonset of amber or violating the red light by about 33%

    Safety impact of connected and autonomous vehicles on motorways: a traffic microsimulation study

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    Connected and Autonomous Vehicles (CAVs) promise to improve road safety greatly. Despite the numerous CAV trials around the globe, their benefit has yet to be proven using real-world data. The lack of real-world CAV data has shifted the focus of the research community from traditional safety impact assessment methods to traffic microsimulation in order to evaluate their impacts. However, a plethora of operational, tactical and strategic challenges arising from the implementation of CAV technology remain unaddressed. This thesis presents an innovative and integrated CAV traffic microsimulation framework that aims to cover the aforementioned shortcomings.A new CAV control algorithm is developed in C++ programming language containing a longitudinal and lateral control algorithm that for the first time takes into consideration sensor error and vehicle platoon formulation of various sizes. A route-based decision-making algorithm for CAVs is also developed. The algorithm is applied to a simulated network of the M1 motorway in the United Kingdom which is calibrated and validated using instrumented vehicle data and inductive loop detector data. Multiple CAV market penetration rate, platoon size and sensor error rate scenarios are formulated and evaluated. Safety evaluation is conducted using traffic conflicts as a safety surrogate measure which is a function of time-to-collision and post encroachment time. The results reveal significant safety benefit (i.e. 10-94% reduction of traffic conflicts) as CAV market penetration increases from 0% to 100%; however, it is underlined that special focus should be given in the motorway merging and diverging areas where CAVs seem to face the most challenges. Additionally, it is proven that if the correct CAV platoon size is implemented at the appropriate point in time, greater safety benefits may be achieved. Otherwise, safety might deteriorate. However, sensor error does not affect traffic conflicts for the studied network. These results could provide valuable insights to policy makers regarding the reconfiguration of existing infrastructure to accommodate CAVs, the trustworthiness of existing CAV equipment and the optimal platoon size that should be enforced according to the market penetration rate.Finally, in order to forecast the conflict reduction for any given market penetration rate and understand the underlying factors behind traffic conflicts in a traffic microsimulation environment in-depth, a hierarchical spatial Bayesian negative binomial regression model is developed, based on the simulated CAV data. The results exhibit that besides CAV market penetration rate, speed variance across lanes significantly affects the production of simulated conflicts. As speed variance increases, the safety benefit decreases. These results emphasize the importance of speed homogeneity between lanes in a motorway as well as the increased risk in the motorway merging/diverging areas.</div

    Transportation evacuation strategies based on vehicular disaster management system in urban network environment Zubaida

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    The importance of emergency response systems have grown tremendously in the recent times due to the many manmade and natural disasters in recent years such as September 2001, July 2005 London bombings and the 2011 Japan earthquake and tsunami disaster. Disasters cost huge human, social and financial losses. For example, in Typhoon Haiyan, as of November 2013, the official death toll from Philippines‟s devastating storm has passed 10,000 people. In addition, based on early estimates, the reconstruction costs could come to as much as $20bn (£12.3bn). Conventional methods for disaster management have shown little prospects of realizing the true potential of current and emerging technologies.This PhD research aims to propose and evaluate a disaster management system based on the emerging ICT technologies with a focus on transportation in urban environments. This work is presented on an Intelligent Disaster Management System based on Vehicular Ad hoc Networks (VANETs) and Cloud Computing. Our research objective is to increase the safety and system efficiency, to reduce the accidents, congestion, and manage the emergencies and disasters. The effectiveness of the intelligent system has been demonstrated through modelling the impact of disaster on real city transport environments and compares it with the case where the intelligent proposed system was in place, and ability of generalizing the concept was increased through applying the proposed system on different cities. By applying our system, substantial benefits have been achieved in terms of improved and balanced traffic flow and smooth evacuation rates.Furthermore, a micro-simulation software model has been developed which employs the vehicular disaster management system in order to investigate the transportation evacuation strategies potential in reducing the human and economic losses.The particular contribution of my thesis is in the modelling and simulation of the traffic for disaster and evacuation scenarios. To this end, this project uses a range and mix of modelling and simulation technologies including macroscopic and microscopic simulation models; OmniTRANS and S-Paramics transport planning software.xixDuring the course of this PhD, disaster scenarios of varying scales involving 2-3 different cities of various sizes and characteristics have been modelled and analysed, thereby presenting a system which deliver advanced services in managing disasters which results in lower losses.Also, the Average Vehicle Occupancy impact on the evacuation process time has been investigated. Literally, it represents the higher number of car occupancy which means less number of trips required to the evacuation process. The results have shown that AVO contributes effectively in evacuation plans that are in place.Additionally, two different evacuation strategies have been applied and evaluated simultaneously and isolated. Subsequently, either continues the processes or perhaps there is a need to change the strategy where applicable and appropriate. In other words, after propagating the evacuation strategy, the traffic situation has been assessed and observed the effectiveness of the disaster management system on the network by comparing the performance of the proposed system against the traditional system. To sum up, the comparison between both scenarios shows the ability to secure more of vehicles, up to double the number, and hence improve the network performance in terms of safety. Moreover, there is an improvement in flow rate of many critical links. Many blocked links are turned into some reds and blues which means an improvement seemed to occur to the whole network
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