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Analysis and design of freeway incident response systems
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Bibliographic Section
conventional transit along potentially unprofitable carridors. This is an important book, and one which should be mandatory reading for the transportation planner and
policy-maker. It is refreshing in this field to encounter research based on a review of factual evidence, rather than to read another hysterical attack on the auto or on other popular targets of public wrath.
Dissertation Abstracts Investigation of Two-Regirtre’Trafic Flow Models at the Micro- and Macroscopic Levels, Avishai Ceder, Road
Safety Center, Technion Institute, Technion City, Halfa, Israel (dissertation at the Department of Civil Engineering, University of California, Berkeley). A new tragic flow model, designed for description of free-flow and congested-flow regimes, was derived at the microscopic level and was successfully examined at the macroscopic level. Based on extensive traffic flow data, a time-sequence analysis of the data points is proposed which makes it possible to furnish plausible interpretations for observing tratBc phenomena. This thesis consists of four major parts. First, the generalized car-following model is evaluated. This model, designed by a research group from General Motors Corporation, can represent successfully previous micro- and macroscopic approaches of traffic flow theory. Therefore, the steady-state formulation obtained from this generalized car-following model was the basis for evaluating previous theories using 45 data sets concerned with tralhc flow variables. The deficiencies of the various models were identified and the need for investigating new approaches for two-regime traffic behavior was stressed. In the second part, a new model is developed. This model, based on a new car-following sensitivity component, shows that the free-flow regime and the congestedflow regime are fairly well adapted to convexity and concavity properties, respectively, in the speedconcentration relationship. Using drivers’ performance analysis to measure sensitivity, model parameters are defined and evaluated. In light of two-regime phenomenon the suggested model is believed superior in accuracy, simplicity, and clarity to the earlier generalized carfollowing model. In the third part, additional analysis of eleven trathc flow data sets from the same freeway location and for the two-regime approach emphasizes the importance of considering data points with respect to time, particularly for data characterized by peak period conditions. It becomes apparent that the consideration of data points in time sequence results in more reliable and consistent trafhc flow parameters. This analysis shows that the two-regime models, both for the new and previous approaches, well represent the data points, particularly at near-capacity conditions. In the fourth part, the consistency of traffic tlow data, congestion patterns, and the proposed two-regime model is examined in regard to the time-sequence analysis. Based on this consistency evaluation it is realized both quantitatively and \qualitatively that there is sign&ant high consistency in regard to: observed maximum flow
characteristics, resulting model parameters, and the observed tratiic phenomena during morning peak period conditions. The overall conclusion reached in this thesis is that the proposed two-regime tragic flow model and the proposed timesequence procedure satisfy the purposes for which they were conceived, and, because of their desirable characteristics, both the model and the procedure should be considered at the micro- and macroscopic levels. The Rationalisation of Airline Networks within Western Europe with special reference to Swissair, John A. Greig, Canadian Transport Commission, Congill Building, 275 Slater St., Ottawa KIA ON9, Canada (dissertation at the London School of Economics and Political Science). In the first half of the thesis the need for the network rationalizations and the means by which to implement them are considered. European airlines, reflecting the peculiarities of their operating environment, serve overextended networks of short, low density routes which imply high cost operations. It is proposed that the overextended European networks should be combined thereby amalgamating traflic onto fewer high density routes. The contraction would involve the changing of direct routes into circuitous, multisector routes. Implementation could be facilitated by extending the bilateral exchange of traflic rights so as to gain mutual advantage for the airlines. The benefits of implementing the route reconfiguration are measured in the second half of the thesis. A heuristic model with inputs from graph theory and optimisation theory is designed to identify the network on which an airline can best serve a set pattern of tragic demands. The model is used to simulate application of the proposed rationalisatlon on Swissair’s 1972network and to quantify the advantages which are twofold. First, the airline is able to serve its markets more efficiently with an attendant reduction in operating costs, while second, the passengers gain some combination of better service and cheaper fares. Analysis and Design of Freeway Incident Response Systerms, Chyi Kang Lu, Parsons, Broinckerhoff, Quade and
Douglas, 25 Maiden Lane, San Francisco, CA 94108 (dissertation in the Department of Civil Engineering, University of California, Berkeley). TratBc incidents on urban freeways require prompt response of an effective detection and service system to minimize tratbo delay and increase motorist safety. Analyzed in this study are the basic functions and essential components of an incident response system, the interac-
Bibliographic Section
conventional transit along potentially unprofitable carridors. This is an important book, and one which should be mandatory reading for the transportation planner and
policy-maker. It is refreshing in this field to encounter research based on a review of factual evidence, rather than to read another hysterical attack on the auto or on other popular targets of public wrath.
Dissertation Abstracts Investigation of Two-Regirtre’Trafic Flow Models at the Micro- and Macroscopic Levels, Avishai Ceder, Road
Safety Center, Technion Institute, Technion City, Halfa, Israel (dissertation at the Department of Civil Engineering, University of California, Berkeley). A new tragic flow model, designed for description of free-flow and congested-flow regimes, was derived at the microscopic level and was successfully examined at the macroscopic level. Based on extensive traffic flow data, a time-sequence analysis of the data points is proposed which makes it possible to furnish plausible interpretations for observing tratBc phenomena. This thesis consists of four major parts. First, the generalized car-following model is evaluated. This model, designed by a research group from General Motors Corporation, can represent successfully previous micro- and macroscopic approaches of traffic flow theory. Therefore, the steady-state formulation obtained from this generalized car-following model was the basis for evaluating previous theories using 45 data sets concerned with tralhc flow variables. The deficiencies of the various models were identified and the need for investigating new approaches for two-regime traffic behavior was stressed. In the second part, a new model is developed. This model, based on a new car-following sensitivity component, shows that the free-flow regime and the congestedflow regime are fairly well adapted to convexity and concavity properties, respectively, in the speedconcentration relationship. Using drivers’ performance analysis to measure sensitivity, model parameters are defined and evaluated. In light of two-regime phenomenon the suggested model is believed superior in accuracy, simplicity, and clarity to the earlier generalized carfollowing model. In the third part, additional analysis of eleven trathc flow data sets from the same freeway location and for the two-regime approach emphasizes the importance of considering data points with respect to time, particularly for data characterized by peak period conditions. It becomes apparent that the consideration of data points in time sequence results in more reliable and consistent trafhc flow parameters. This analysis shows that the two-regime models, both for the new and previous approaches, well represent the data points, particularly at near-capacity conditions. In the fourth part, the consistency of traffic tlow data, congestion patterns, and the proposed two-regime model is examined in regard to the time-sequence analysis. Based on this consistency evaluation it is realized both quantitatively and \qualitatively that there is sign&ant high consistency in regard to: observed maximum flow
characteristics, resulting model parameters, and the observed tratiic phenomena during morning peak period conditions. The overall conclusion reached in this thesis is that the proposed two-regime tragic flow model and the proposed timesequence procedure satisfy the purposes for which they were conceived, and, because of their desirable characteristics, both the model and the procedure should be considered at the micro- and macroscopic levels. The Rationalisation of Airline Networks within Western Europe with special reference to Swissair, John A. Greig, Canadian Transport Commission, Congill Building, 275 Slater St., Ottawa KIA ON9, Canada (dissertation at the London School of Economics and Political Science). In the first half of the thesis the need for the network rationalizations and the means by which to implement them are considered. European airlines, reflecting the peculiarities of their operating environment, serve overextended networks of short, low density routes which imply high cost operations. It is proposed that the overextended European networks should be combined thereby amalgamating traflic onto fewer high density routes. The contraction would involve the changing of direct routes into circuitous, multisector routes. Implementation could be facilitated by extending the bilateral exchange of traflic rights so as to gain mutual advantage for the airlines. The benefits of implementing the route reconfiguration are measured in the second half of the thesis. A heuristic model with inputs from graph theory and optimisation theory is designed to identify the network on which an airline can best serve a set pattern of tragic demands. The model is used to simulate application of the proposed rationalisatlon on Swissair’s 1972network and to quantify the advantages which are twofold. First, the airline is able to serve its markets more efficiently with an attendant reduction in operating costs, while second, the passengers gain some combination of better service and cheaper fares. Analysis and Design of Freeway Incident Response Systerms, Chyi Kang Lu, Parsons, Broinckerhoff, Quade and
Douglas, 25 Maiden Lane, San Francisco, CA 94108 (dissertation in the Department of Civil Engineering, University of California, Berkeley). TratBc incidents on urban freeways require prompt response of an effective detection and service system to minimize tratbo delay and increase motorist safety. Analyzed in this study are the basic functions and essential components of an incident response system, the interac-