Traffic Management Tool Research Articles

Parking Policy and Urban Mobility Level of Service – System Dynamics as a Modelling Tool for Decision Making

Parking policy is still the most directly available instrument for managing traffic demand in many cities. But policy design is subject to difficulties resulting from the complexity of the urban mobility system. This article presents a model framework, based on a system dynamics approach, aimed at assessing the effectiveness of parking policy and quantitatively identifying optimal design at an aggregate spatial level under a level of service maximization objective. An application to a city is developed and the results are discussed in view of their qualitative outcomes and quantitative validity and robustness. It is argued that system dynamics addresses several needs of modellers and decision makers regarding urban parking policy assessment, particularly if parking is used as a traffic management tool. The qualitative results of the model coincide with the prescriptions that would come from the economic theory, even with an objective function based on level of service instead of a broader indicator of efficiency. At the quantitative level, the validation testing of the model application with the available data provided positive indications and no case to reject that a quantitative accurateness useful for policy prescription could be attained provided that some data gaps are fulfilled. The necessary data for calibration seems to be possible to obtain by feasible local empirical observations.

Reporting Policies of ISPs: Do General Terms and Conditions (GTCs) Match with the Reality?

Technological progress allows Internet Service Providers (ISPs) to carry out network management practices in a discriminatory fashion without being detected by their customers. This creates an opportunity that providers will exploit this information asymmetry in an opportunistic way by blocking and/or throttling certain services and applications without informing their customers in an adequate fashion that their Internet service is a restricted one. The main objective of this paper is to investigate the extent to which reporting policies – as implemented through the General Terms and Conditions (GTCs) – of selected ISPs match with the display of discriminatory behavior by those ISPs as shown by Grove & Agic, (2012). Our analysis examines whether ISPs in Europe and the USA are informing their subscribers adequately about discriminatory traffic management. We, thus, analyze GTCs, signed between ISPs and their subscribers by applying a cross-country/provider approach, focusing on three main aspects of the contractual agreement: (1) availability of service, (2) obligations of the customers and (3) the contractual agreements concerning any intervention in services by ISPs. First results show that no significant evidence of contractual transparency regarding the actual adverse deployment of Deep Packet Inspection (DPI) and similar traffic management tools by the ISPs could be found. This supports the general goal to promote transparency regarding ISPs´ traffic management routines by suggesting compulsory rules that should oblige providers to make more accurate statements in terms of their general business practices. For policy makers, this is yet another factor that needs to be taken into account regarding potential regulatory interventions in this field and an explicit network neutrality stipulation may be required in order to safeguard the openness of the Internet and protect consumers´ basic rights of information and well-grounded choice.

Integrated Ramp Metering and Mainstream Traffic Flow Control on Freeways Using Variable Speed Limits

In this paper we integrate local ramp metering (RM) with Mainstream Traffic Flow Control (MTFC) enabled via Variable Speed Limits (VSL), which is a recently proposed freeway traffic management tool. The integration is performed by the extension of an existing simple local cascade feedback MTFC controller via a split-range-like scheme. The integrated controller remains simple yet efficient and suitable for field implementation. The controller is evaluated in simulation and compared to stand-alone RM or MTFC via VSL, as well as optimal control results. The controller's performance is shown to meet the specifications and to approach the optimal control results for the investigated scenario.

Comparison of Local Feedback Controllers for the Mainstream Traffic Flow on Freeways Using Variable Speed Limits

Mainstream traffic flow control (MTFC) on freeways, enabled via variable speed limits (VSL), is a traffic management tool capable of avoiding or, at least, postponing congestion formation on freeway bottlenecks, and may complement other existing measures. Two simple feedback controllers for local MTFC via VSL are proposed. Both controllers are evaluated and compared to a previously developed local MTFC feedback cascade controller and to a sophisticated optimal control approach. All feedback controllers rely on readily available real-time measurements, are simple and robust, and take into account a number of practical and safety restrictions; therefore, they are suitable for implementation in the field as a new or as part of an existing intelligent transportation systems infrastructure. The evaluations are conducted for a hypothetical freeway network by use of a validated second-order macroscopic traffic flow model. The results show that the feedback controllers exhibit a satisfactory control behavior and, indeed, approach the optimal control results. Recommendations for the operation of the feedback controllers are given.

Investigating Benefits of IntelliDrive in Freeway Operations: Lane Changing Advisory Case Study

Abstract IntelliDrive, the integration of vehicles and the infrastructure through wireless communication, has generated great interest in the transportation community. It is widely expected that IntelliDrive will support significantly improved transportation operations. However, there have been few studies investigating (1) how IntelliDrive will be used to improve operations, and (2) how to estimate expected benefits of IntelliDrive operations applications. In this study, the research team investigated the application of IntelliDrive to address merging conflicts created by freeway on-ramps. Although merging conflicts contribute significantly to freeway congestion, transportation engineers have limited options with existing traffic surveillance and management tools. IntelliDrive offers the potential for more active management of the surface transportation system, providing capabilities that may be of significant benefit in ramp management. In this research, a lane changing advisory algorithm was developed ...

Integrated Ramp Metering and Mainstream Traffic Flow Control on Freeways Using Variable Speed Limits

We integrate local Ramp Metering (RM) with Mainstream Traffic Flow Control (MTFC) enabled via Variable Speed Limits (VSL), which is a recently proposed freeway traffic management tool. The integration is performed by the extension of an existing simple local cascade feedback MTFC controller via a split-range-like scheme. The integrated controller remains simple yet efficient and suitable for field implementation. The controller is evaluated in simulation and compared to stand-alone RM or MTFC via VSL, as well as optimal control results. The controller's performance is shown to meet the specifications and to approach the optimal control results for the investigated scenario.

A Complementary Modularized Ramp Metering Approach Based on Iterative Learning Control and ALINEA

Ramp metering is an effective tool for traffic management on freeway networks. In this paper, we apply iterative learning control (ILC) to address ramp metering in a macroscopic-level freeway environment. By formulating the original ramp metering problem as an output regulating and disturbance rejection problem, ILC has been applied to control the traffic response. The learning mechanism is further combined with Asservissement Lineaire d'Entree Autoroutiere (ALINEA) in a complementary manner to achieve the desired control performance. The ILC-based ramp metering strategy and the modified modularized ramp metering approach based on ILC and ALINEA in the presence of input constraints are also analyzed to highlight the advantages and the robustness of the proposed methods. Extensive simulations are given to verify the effectiveness of the proposed approaches.

Local Feedback-Based Mainstream Traffic Flow Control on Motorways Using Variable Speed Limits

Recent research has proposed mainstream traffic flow control (MTFC), enabled via variable speed limits (VSLs), as a novel motorway traffic management tool and has demonstrated its efficiency based on sophisticated optimal control methods that may face difficulties in practical field implementations. A simple local MTFC feedback controller is designed in this paper, taking into account a number of practical requirements and restrictions. The MTFC controller relies only on readily available real-time measurements (no online model usage and no demand predictions are needed) and is therefore robust and suitable for field implementations. The controller is evaluated in simulation and compared with optimal control results. Despite its simplicity, the new controller's performance is shown to approach the optimal control results while considering several practical and safety restrictions for a number of investigated scenarios.

Tipping point: The narrow path between automation acceptance and rejection in air traffic management

Capacity limits on the air traffic management (ATM) system are of global concern. One solution to increase the efficiency of existing ATM system is through the implementation of advanced automation. However, past experience suggests ATCOs are selective and critical about the forms of automation they are given. Therefore, this study aimed to determine if a threshold or tipping point exists, a point after which users (Air Traffic Control Operators; ATCOs) of automation are no longer willing to accept or cooperate with the automation. 500 Air Traffic Control Operators completed an on-line survey that comprised a series of demographic questions as well as two hypothetical but plausible futuristic air traffic management tools. Each tool contained seven different situations involving different levels of automation involvement ranging from fully manual operation to fully automated. Participants were asked to rate on a five point Likert scale the extent to which they agreed with the statements describing their interaction with the new tools. The results revealed a ‘tipping point’ in automation acceptance/rejection reflecting the point where the applied level of automation shifted the locus of decision-making away from the operator. The results are discussed from a theoretical and applied perspective.

Dynamic Traffic Assignment under Uncertainty: A Distributional Robust Chance-Constrained Approach

This paper provides a chance-constrained programming approach for transportation planning and operations under uncertainty. The major contribution of this paper is to approximate a joint chance-constrained Cell Transmission Model based System Optimum Dynamic Traffic Assignment with only partial distributional information about uncertainty as a linear program which is computationally efficient. Numerical experiments have been conducted to show the performance of the proposed approach compared with other two workable approaches based on a cumulative distribution function and a sampling method. This new approach can be used as a pragmatic tool for system optimum dynamic traffic control and management.

Evaluation of different contraflow strategies for hurricane evacuation in Charleston, South Carolina

Limited specific evidence is available on the effectiveness of using contraflow as an evacuation traffic management tool. This study was conducted to determine the best combination of strategy options for evacuating Charleston, SC, along route I-26 during the event of a hurricane or other events. PARAMICS microscopic traffic simulator was used to evaluate the impact of each combination of evacuee response timing and traffic control strategy, such as contraflow, with respect to average vehicular travel time and evacuation duration. Analysis revealed the combination of management strategies that created the lowest evacuation durations and travel times for several types of anticipated evacuee responses. Furthermore, a proposed reconfiguration of the I-526/I-26 interchange for contraflow operations produced additional savings in travel times and evacuation durations. These findings support the use of all lanes for contraflow during all evacuations and provide justification to examine a possible reconfiguration of the I-526/I-26 interchange for use during evacuations.

A method of developing regional road traffic noise management strategies

Road traffic noise management strategies or noise action plans are a necessary tool for pro-active road traffic noise management. A method is proposed for regional scale noise action plans, in part using noise mapping, which is flexible towards various data qualities. A six step method is proposed which links GIS data to road traffic noise calculation methods with the final strategies being presented in GIS format. A ‘Parcel Priority Index’ and a ‘Link Priority Index’ are presented as key variables in the production of regional strategies and planning visions on a road link basis. The noise management strategy method presented is used on a large regional area in South East Queensland, Australia which covers seven local government areas. The results presented indicate the method is successful in prioritising road links equitably for detailed road traffic noise management actions.

Using incentives as traffic management tool: empirical results of the "peak avoidance" experiment

Although positive incentives have been successfully applied in various domains to influence behavior, they have received limited attention in transportation. This paper reports on the Dutch ‘Spitsmijden’ (‘Peak Avoidance’) project, in which travelers received positive incentives if they avoided travelling in the peak by car. Incentives could be financial (3 to 7 EURO per day) or credits to earn a smartphone at the end of the experiment. Travelers' responses were measured using electronic detection equipment and travel diaries. The results of the study indicate that positive incentives are able to reduce the amount of peak traffic of the participants by about 60%. Travelers mainly responded to the incentives by shifting their car trips to the periods before and after the peak period. Although the experiment was intended to achieve a structural change in travel behavior, we observed that travelers returned to the peak period when the incentives ended.

What Local Policy Makers Should Know about Urban Road Charging: Lessons from Worldwide Experience

Congestion costs are emerging as one of the most important challenges faced by metropolitan planners and transport authorities in developed economies. In the United States, these costs were as high as $78 billion in 2005 and are growing as a result of rapid increases in travel delays. In order to solve the current and severe levels of congestion, the U.S. Department of Transportation has recently started a program to initiate congestion pricing in five metropolitan areas. In this context, it is important to identify factors that influence successful implementation, as well as the problems or difficulties associated with charging projects. The authors review, synthesize, and analyze worldwide experience with urban road charging in order to extract lessons for policy makers who are considering the implementation of congestion pricing projects and for those who are interested in the introduction of traffic management tools to regulate entrance to city centers.

Optimal mainstream traffic flow control of large-scale motorway networks

The continuously increasing daily traffic congestions on motorway networks around the world call for innovative control measures that would drastically improve the current traffic conditions. Mainstream traffic flow control (MTFC) is proposed as a novel and efficient motorway traffic management tool, and its possible implementation and principal impact on traffic flow efficiency is analysed. Variable speed limits, suitably operated and enforced, is considered as one (out of several possible) way(s) for MTFC realisation, either as a stand-alone measure or in combination with ramp metering. A previously developed, computationally efficient software tool for optimal integrated motorway network traffic control including MTFC is applied to a large-scale motorway ring-road. It is demonstrated via several investigated control scenarios that traffic flow can be substantially improved via MTFC with or without integration with coordinated ramp metering actions.

Residential Off-Street Parking Impacts on Car Ownership, Vehicle Miles Traveled, and Related Carbon Emissions

Parking is a key element of the street and highway system. Parking supply affects driving demand by changing the underlying cost structure associated with mode choice decisions. It also affects levels of auto ownership by changing the cost of auto ownership. These two facts combine to make parking management an important and powerful tool for both traffic and air-quality management. A pilot analysis of demographics, highway and transit access, and off-street parking in two New York City neighborhoods strongly suggests that the provision of residential off-street parking affects commuting behavior. Moreover, the type of parking provision plays a strong role in determining mode share. Accessory parking that is adjacent to a home, in a garage or driveway, seems more likely to generate auto commutes than does parking in commercial centralized lots. This analysis, which was followed by testing plausible development scenarios, shows that the city's residential off-street parking regulations will undermine its own vision for a sustainable future.

Review of urban traffic management and the impacts of new vehicle technologies

Traffic congestion is a growing problem in most urban areas across the world. In recent years, the problem has often been tackled by management of existing capacity rather than the traditional concept of more road building. This requires efficient traffic management tools and has led to widespread implementation of advanced traffic control systems integrated within a wider urban traffic management (UTM) environment. UTM systems collect data from various sources, process and manage the data and use this information to implement various measures to manage traffic. While infrastructure-based UTM systems continue to develop, there is now also a rapid market-driven development of vehicle technologies and in-vehicle driver support systems. Driver information and satellite navigation (sat-nav) systems are two examples already in widespread use, whereas other applications under research and development include intelligent speed adaptation (ISA), adaptive cruise control (ACC) and various other safety-related applications. This study will firstly present state-of-the-art reviews of UTM and in-vehicle systems. It will then discuss the potential impacts of new in-vehicle systems on UTM and opportunities for beneficial cooperation between the two. The research described in the study has been undertaken within a collaborative project FUTURES, funded by the Engineering and Physical Sciences Research Council (EPSRC).

Optimal Mainstream Traffic Flow Control of Motorway Networks

Abstract The continuously increasing daily traffic congestions on motorway networks call for innovative control measures that would drastically improve the current traffic conditions. Mainstream traffic flow control (MTFC) is proposed as a novel motorway traffic management tool. Its possible implementation and principal impact on traffic flow efficiency is analysed. Variable speed limits, suitably operated and enforced, is considered as one (out of several possible) way(s) for MTFC realisation, either as a stand-alone measure or in combination with ramp metering. A previously developed software tool for optimal integrated motorway network traffic control including MTFC is applied to a large-scale motorway ring-road. It is demonstrated via several investigated control scenarios that traffic flow can be substantially improved via MTFC with or without integration with coordinated ramp metering actions.

The Welfare Impacts of Broadband Network Management: Can Broadband Service Providers Be Trusted?

The extent to which broadband Internet service providers can engage in reasonable traffic management when faced with potentially congestion-causing applications like BitTorrent or other file-sharing applications is currently the subject of heated debate. This Paper provides a formal economic analysis of the likely welfare consequences of broadband Internet network management that is directed at controlling network congestion. We show that it is socially desirable to charge a congestion premium or utilize other traffic management techniques when congestion-causing applications impose a congestion externality and degrade the experience of other users. The most efficient traffic management actions would be targeted at applications that cause congestion externalities and not upon all applications generally. The model also suggests congestion externalities caused by applications may vary depending upon network capacity constraints and protocols. As a result, assessment of the reasonableness of network management practices is most logical on a case-by-case basis rather than imposition of a single bright-line test. Instead, our model indicates that if it is shown that a congestion externality is present and that a traffic management tool directly remedies that externality, it is appropriate to presume that this type of traffic management by a private firm is legitimate and welfare enhancing.

Testing the Surface Management System (SMS) Through Operational Trials with Air Traffic Control and Airline Participants

The Surface Management System (SMS) aims to increase airport capacity and decrease surface gridlock, which are goals consistent with the Federal Aviation Administration's (FAA) National Airspace System Operational Evolution Plan (FAA, 2002). An operational trial was conducted to evaluate the initial design of the SMS traffic management tools. Although the dataset was small, participant responses were positive on four dimensions (usefulness, frequency of use, perceived accuracy, and ease of use) for nearly all of the six traffic management tools. Participant debriefs highlighted additional issues including the effects of SMS on coordination between Air Traffic Management facilities. This paper outlines the conduct of the operational trials and explores two of the major issues raised by the observations made during the trials.