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Modeling the Behavior of Traffic Information Providers

Tue, 2015-12-29 02:54
Two models are used to represent the locational behavior of traffic information providers. The characteristics which make traffic information unique as a service good are discussed and exploited in the models to show how the behavior of information providers might differ from that of firms in a traditional market. Questions are addressed regarding the clustering of competing providers and the efficiency of the resulting output. The purpose of this paper is to contribute to the study of the economics of the traffic information industry and of the role of public financing versus private competition.

Modeling the Behavior of Traffic Information Providers

Tue, 2015-12-29 02:54
Two models are used to represent the locational behavior of traffic information providers. The characteristics which make traffic information unique as a service good are discussed and exploited in the models to show how the behavior of information providers might differ from that of firms in a traditional market. Questions are addressed regarding the clustering of competing providers and the efficiency of the resulting output. The purpose of this paper is to contribute to the study of the economics of the traffic information industry and of the role of public financing versus private competition.

A Probabilistic Model and a Software Tool for AVCS Longitudinal Collision/Safety

Tue, 2015-12-29 02:54
This paper develops a probabilistic model and a software tool for analyzing longitudinal collision/safety between two automated vehicles. The input parameters are the length of the gap between the two vehicles, the common speed prior to the failure, the reaction delay of the following vehicle and a bivariate joint distribution of the deceleration rates of the two vehicles. The output includes the probability of a collision and also the probability distribution of the relative speed at collision time. This model was used to compare the safety consequences associated with the platooning and "free-agent" vehicle-following rules. It was found that the free-agent vehicle following rule implemented with a potential technology of fast and accurate emergency deceleration, under some reasonable conditions, can virtually avoid collisions while offering a high freeway capacity previously thought possible only under the platooning rule.

A Network Layer for Intelligent Vehicle Highway Systems

Tue, 2015-12-29 02:54
The objective of this paper is to design the network layer of a communication stack to be used in Automated Highway Systems (AHS). The communication model the authors propose allows cars to form private subnets, the configuration of which can change dynamically. Each car be part of multiple subnets and can send broadcast, multicast and point-to-point messages to other vehicles (both on the same subnet and on others, through a routing mechanism). Each subnet is managed by a server: a car that is in charge of accepting/rejecting join requests and of keeping a consistent state within the subnet. Finally the authors propose an AHS addressing scheme and an API implementing the discussed functionality.

A Probabilistic Model and a Software Tool for AVCS Longitudinal Collision/Safety

Tue, 2015-12-29 02:54
This paper develops a probabilistic model and a software tool for analyzing longitudinal collision/safety between two automated vehicles. The input parameters are the length of the gap between the two vehicles, the common speed prior to the failure, the reaction delay of the following vehicle and a bivariate joint distribution of the deceleration rates of the two vehicles. The output includes the probability of a collision and also the probability distribution of the relative speed at collision time. This model was used to compare the safety consequences associated with the platooning and "free-agent" vehicle-following rules. It was found that the free-agent vehicle following rule implemented with a potential technology of fast and accurate emergency deceleration, under some reasonable conditions, can virtually avoid collisions while offering a high freeway capacity previously thought possible only under the platooning rule.

A Network Layer for Intelligent Vehicle Highway Systems

Tue, 2015-12-29 02:54
The objective of this paper is to design the network layer of a communication stack to be used in Automated Highway Systems (AHS). The communication model the authors propose allows cars to form private subnets, the configuration of which can change dynamically. Each car be part of multiple subnets and can send broadcast, multicast and point-to-point messages to other vehicles (both on the same subnet and on others, through a routing mechanism). Each subnet is managed by a server: a car that is in charge of accepting/rejecting join requests and of keeping a consistent state within the subnet. Finally the authors propose an AHS addressing scheme and an API implementing the discussed functionality.

Evaluation Framework for Commercial Vehicle Responses to Congestion Pricing

Tue, 2015-12-29 02:54
In this report, a framework for analyzing the impacts of congestion pricing on commercial vehicles is developed based on microeconomics principle and past theoretical studies of congestion pricing. The model can be used to assess the short-run impacts of congestion pricing, as well as other forms of toll roads, on the welfare of commercial vehicle operators. The report starts out by identifying the relationship between value of time and the welfare gain/loss induced by the introduction of congestion pricing on an exiating facility. Under the assumptions employed in this study, which limit the scope to the short-run analysis, the essential information required to use the model are the roadway and vehicle operating charcteristics, toll schedule, and the cumulative distribution for the value of time. Also, the marginal social cost function with respect to traffic volume must be known to analyze the overall impact on the society. The report also explores potential approaches to derive empirical demand and supply functions within a short-run framework.

Research and Testing for ITS Deployment and Operation

Tue, 2015-12-29 02:54
This paper identifies the elements of a publicly sponsored research and testing (R&T) program that best serves the needs of ITS deployment. Many of these needs derive from the decentralized, diverse, network-system nature of ITS. Relevant R&T should help integrate ITS technologies, data flows, services, organizations and users into effective, coordinated systems that can be tailored to fit diverse local needs. A key theme in an effective R&T program will be the effective generation and application of information, not only for users, but for planners, implementors and operators.

Evaluation Framework for Commercial Vehicle Responses to Congestion Pricing

Tue, 2015-12-29 02:54
In this report, a framework for analyzing the impacts of congestion pricing on commercial vehicles is developed based on microeconomics principle and past theoretical studies of congestion pricing. The model can be used to assess the short-run impacts of congestion pricing, as well as other forms of toll roads, on the welfare of commercial vehicle operators. The report starts out by identifying the relationship between value of time and the welfare gain/loss induced by the introduction of congestion pricing on an exiating facility. Under the assumptions employed in this study, which limit the scope to the short-run analysis, the essential information required to use the model are the roadway and vehicle operating charcteristics, toll schedule, and the cumulative distribution for the value of time. Also, the marginal social cost function with respect to traffic volume must be known to analyze the overall impact on the society. The report also explores potential approaches to derive empirical demand and supply functions within a short-run framework.

Research and Testing for ITS Deployment and Operation

Tue, 2015-12-29 02:54
This paper identifies the elements of a publicly sponsored research and testing (R&T) program that best serves the needs of ITS deployment. Many of these needs derive from the decentralized, diverse, network-system nature of ITS. Relevant R&T should help integrate ITS technologies, data flows, services, organizations and users into effective, coordinated systems that can be tailored to fit diverse local needs. A key theme in an effective R&T program will be the effective generation and application of information, not only for users, but for planners, implementors and operators.

Individual Vehicle Speed Estimation Using Single Loop Inductive Waveforms

Tue, 2015-12-29 02:54
Travel time is the reciprocal of speed and is a useful measure of road congestion and traffic system performance. Travel time is also a basic traffic variable that is used in many Intelligent Transportation System (ITS) strategies such as route guidance, incident detection, and traveler information systems. Previously, speeds were mainly acquired from double inductive loops configured as speed traps, since single loop speed estimates based on assumptions of a constant vehicle length were inaccurate. However, more accurate measurements of speed can now be accomplished with single loops by utilizing inductive waveforms of vehicles that are outputed from newer detector cards. An algorithm using signal processing and statistical methods was developed to extract speeds from inductive waveforms. The results show that the proposed algorithm performs better than conventional single loop estimation methods. The results also show that the algorithm is robust under different traffic conditions and is transferrable across surveillance sites without the need for recalibration. The use of the extensive single loop surveillance infrastructure is a cost-effective way of obtaining more accurate network-wide travel time information.

Individual Vehicle Speed Estimation Using Single Loop Inductive Waveforms

Tue, 2015-12-29 02:54
Travel time is the reciprocal of speed and is a useful measure of road congestion and traffic system performance. Travel time is also a basic traffic variable that is used in many Intelligent Transportation System (ITS) strategies such as route guidance, incident detection, and traveler information systems. Previously, speeds were mainly acquired from double inductive loops configured as speed traps, since single loop speed estimates based on assumptions of a constant vehicle length were inaccurate. However, more accurate measurements of speed can now be accomplished with single loops by utilizing inductive waveforms of vehicles that are outputed from newer detector cards. An algorithm using signal processing and statistical methods was developed to extract speeds from inductive waveforms. The results show that the proposed algorithm performs better than conventional single loop estimation methods. The results also show that the algorithm is robust under different traffic conditions and is transferrable across surveillance sites without the need for recalibration. The use of the extensive single loop surveillance infrastructure is a cost-effective way of obtaining more accurate network-wide travel time information.

Evaluation of On-ramp Control Algorithms

Tue, 2015-12-29 02:54
Ramp metering, or on-ramp control, is designed to determine a metering rate for each controlled on-ramp based on traffic conditions of part or whole of the corridor. This paper reviews the most popular and theoretically attractive ramp metering algorithms. A classification scheme and a set of evaluation criteria to aid the categorization and qualitative assessment of the selected metering algorithms are developed. Possible improvements and areas for further research are identified.

Evaluation of On-ramp Control Algorithms

Tue, 2015-12-29 02:54
Ramp metering, or on-ramp control, is designed to determine a metering rate for each controlled on-ramp based on traffic conditions of part or whole of the corridor. This paper reviews the most popular and theoretically attractive ramp metering algorithms. A classification scheme and a set of evaluation criteria to aid the categorization and qualitative assessment of the selected metering algorithms are developed. Possible improvements and areas for further research are identified.