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Highway Traffic Analysis and Design PDF

380 Pages·1974·24.325 MB·English
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HIGHWAY TRAFFIC ANALYSIS AND DESIGN HIGHWAY TRAFFIC ANALYSIS AND DESIGN R. J. Salter Senior Lecturer in Civil Engineering University of Bradford MACMILLAN EDUCATION © R. J. Salter 1974 Softcover reprint ofthe hardcover 1st edition 1974 978-0-333-15478-6 All rights reserved. No part of this publication may be reproduced or transmitted, in any form or by any means, without permission. First published 1974 by THE MACMILLAN PRESS LTD London and Basingstoke Associated companies in New York Dublin Melbourne Johannesburg and Madras SBN 333 15478 9 ISBN 978-1-349-02095-9 ISBN 978-1-349-02093-5 (eBook) DOI 10.1007/978-1-349-02093-5 Contents Preface vii PART I TRAFFIC ANALYSIS AND PREDICTION 1. Introduction to the transportation planning process 3 2. The transportation study area 8 3. The collection of existing travel data I4 4. The external cordon and screenline surveys I8 5. Other surveys 22 6. Trip generation 25 7. Trip distribution 35 8. Modal split 53 9. Traffic assignment 64 I 0. The evaluation of transportation proposals 7I PART 2 ANALYSIS AND DESIGN FOR HIGHWAY TRAFFIC II. The capacity of highways between intersections 95 I2. Headway distributions in highway traffic flow 107 13. The relationship between speed, flow and density of a highway traffic stream 125 I4. The distribution of vehicular speeds in a highway traffic stream 135 IS. The macroscopic determination of speed and flow of a highway traffic stream 145 I6. Intersections with priority control ISO I7. Driver reactions at priority intersections 156 I8. Delays at priority intersections I63 I9. A simulation approach to delay at priority intersections 171 20. Weaving action at intersections I82 21. Lengths of weaving sections calculated in accordance with the Highway Capacity Manual I89 22. Queueing processes in traffic flow 201 23. New forms of single level intersections 2II 24. Grade-separated junctions 2I9 25. The environmental effects of highway traffic noise 229 26. The environmental effects of highway traffic pollution 245 27. Traffic congestion and restraint 250 vi CONTENTS PART 3 TRAFFIC SIGNAL CONTROL 28. Introduction to traffic signals 269 29. Warrants for the use of traffic signals 271 30. Phasing 275 31. Signal aspects and the intergreen period 278 32. Vehicle-actuated signal facilities 280 33. The effect of roadway and environmental factors on the capacity of a traffic-signal approach 282 34. The effect of traffic factors on the capacity of a traffic-signal approach 287 35. Determination of the effective green time 291 36. Optimum cycle times for an intersection 294 37. The timing diagram 299 38. Early cut-off and late-start facilities 302 39. The effect of right-turning vehicles combined with straight-ahead and left-turning vehicles 306 40. The ultimate capacity of the whole intersection 311 41. The optimisation of signal-approach dimensions 314 42. Optimum signal settings when saturation flow falls during the green period 319 43. Delay at signal-controlled intersections 324 44. Determination of the optimum cycle from a consideration of delays on the approach 329 45. Average queue lengths at the commencement of the green period 336 46. The co-ordination of traffic signals 342 4 7. Time and distance diagrams for linked traffic signals 344 48. Platoon dispersion and the linking of traffic signals 349 49. The prediction of the dispersion of traffic platoons downstream of signals 352 50. The delay offset relationship and the linking of signals 354 51. Some area traffic control systems 363 Appendix 370 Index 373 Preface More than a decade has passed since transport and traffic engineering first became recognised as an academic subject in centres of higher education in the United Kingdom. In this period the interdependence between land use and transport needs has been firmly established and the modelling of the transport system has seen considerable advances. During this same time it has been realised that highway transport demand in urban areas will have to be balanced against the overall social, economic and environmental costs of movement. This book includes the fundamental principles of land use, transport planning techniques and the subsequent economic evaluation of highway schemes. It reviews the analytical and practical aspects of highway traffic flow with sections discussing noise generation and pollution and the principles of congestion restraint and road pricing. Highway intersections are considered in detail. There is a comprehensive treatment of traffic signal control, which ranges from isolated signal-controlled intersections to area-wide signal control. So that many engineers and planners engaged in transport work, but without the benefits of formal tuition, will find this book useful, each section contains questions by which the reader may test his comprehension of the subject matter by reference to the model answers. The author would like to express his thanks to those postgraduate students of transportation at the University of Bradford who made valuable comments on the script and examples; also to Professor C. B. Wilby, Chairman of the Schools of Civil and Structural Engineering, for his encouragement for transportation teaching and research. The author would like to express his appreciation to the following bodies for permission to reproduce their copyright material: Bedfordshire County Council, the Department of the Environment, the Building Research Station, the Eno Foundation, Freeman Fox and Associates, the Greater London Council, Her Majesty's Stationery Office, the Institution of Civil Engineers, the Institution of Highway Engineers, National Research Council, Royal Borough of New Windsor, Traffic Engineering and Control, the Transport and Road Research Laboratory, and Wilbur Smith and Associates. R.J.S. PART 1 TRAFFIC ANALYSIS AND PREDICTION 1 Introduction to the transportation planning process Large urban areas have in the past frequently suffered from transportation congestion. It has been recorded that in the first century vehicular traffic, except for chariots and official vehicles, was prohibited from entering Rome during the hours of daylight. While congestion has existed in urban areas the predominantly pedestrian mode of transport prevented the problem from becoming too serious until the new forms of individual transport of the twentieth century began to demand greater highway capacity. Changes in transport mode frequently produce changes in land-use patterns; for example, the introduction of frequent and rapid rail services in the outer suburbs of London resulted in considerable residential development in the areas adjacent to local stations. More recently the availability of private transport has led to the growth of housing development which cannot economically be served by public transport. In areas of older development however the time scale for urban renewal is so much slower than that which has been recently experienced for changes in the transport mode that the greatest difficulty is being experienced in accommodating the private motor car. Before the early 1950s it was generally believed that the solution to the transportation problem lay in determining highway traffic volumes and then applying a growth factor to ascertain the future traffic demands. Many of the early transportation studies carried out in the United States during this period saw the problem as being basically one of providing sufficient highway capacity and were concerned almost exclusively with highway transport. During the early 1950s however it was realised that there was a fundamental connection between traffic needs and land-use activity. It led to the study of the transportation requirements of differing land uses as the cause of the problem rather than the study of the existing traffic flows. The late 1950s and early 1960s saw the commencement of many land use/transportation surveys in the United Kingdom and the era of transportation planning methodology could have been said to have com menced. Because the planning of transportation facilities is only one aspect of the overall planning process which affects the quality of life in a developed society, the provision of transport facilities is dependent on the overall economic resources available. It is 3 4 TRAFFIC ANALYSIS AND PREDICTION dependent on the value that is placed on such factors as environmental conditions; for some transport facilities are considered to detract from the quality of the environment and others can be considered to improve the environment. Land use and transport planning are also closely connected because the demand for travel facilities is a function of human land activity and conversely the provision of transport facilities has often stimulated land-use activity. Because we are living in a society that is changing rapidly, and in which the rate of change appears to be increasing, it is important for some attempt to be made to develop economic, environmental, land use, population and transport planning policies. The fact that planning attempts in all these fields have not met with con spicuous success in the past decade should be taken as an attempt to improve the methodology rather than an indication that short term plans based on expediency or intuition should be employed. Transportation studies may be carried out to determine the necessity or suitability of a variety of transport systems such as inter-city air-links, a new motorway or a combination of private and public transport modes such as is found in a large urban ised conurbation. The methodology of these surveys will vary in detail-but most transportation surveys that are based on land-use activity tend to be divisible into three major sub-divisions. (i) The transportation survey, in which an attempt is made to take an inventory of the tripmaking pattern as it exists at the present time, together with details of the travel facilities available and the land-use activities and socio-economic factors that can be considered to influence travel. (ii) The production of mathematical models, which attempt to explain the relation ship between the observed travel pattern and the travel facilities, land-use activities and socio-economic factors obtained by the transportation survey. (iii) The use of these mathematical models to predict future transportation needs and to evaluate alternative transportation plans. These three stages of the transport planning process are illustrated in figure 1.1, which shows the procedure used to estimate future travel in the Greater London Area. In the first stage, details of the existing travel pattern together with information on land use and transport facilities are obtained for the area of the study. This area is bounded by an external cordon and so that the origins and destinations of trips within the area can be conveniently described, the study area is divided into traffic zones. Details of the existing travel pattern are obtained by determining the origins and destinations of journeys, the mode of travel and the purpose of the journey. Most surveys obtain information on journeys that have origins in the survey area by a household interview method, which records details of the tripmaking of survey-area residents. In addition there will be some trips that have origins outside the external cordon and destinations within the cordon and others that have neither origin nor destination within the survey area but pass through the study area. Details of these trips will be obtained by interviewing tripmakers as they cross the cordon. Additional surveys will be necessary to obtain details of commercial vehicle trips originating in the survey area and in some circumstances trips made by means of taxis. Information on transport facilities will include details of public transport journey times, the frequency of service, walking and waiting times. For the road network,

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Most books are stored in the elastic cloud where traffic is expensive. For this reason, we have a limit on daily download.