Showing papers in "Transportation Engineering Journal of ASCE in 1973"

Large Diameter Pipe under Combined Loading

Abstract: The writers consider the planning and performance of a full-scale test program on 30 ft. long, 4 ft. diam pipe sections. The combined loadings applied in these tests simulate the force and displacements anticipated to be introduced in the underground portion of the trans-Alaska pipeline under service conditions. Experimental results are presented, and a comparison with theoretical data are included.

Planning for Satellite Airports

Abstract: This study examines the potential role of satellite airports and attempts to define the factors determining the distribution of service and demand among airports serving the same metropolitan area. The analysis indicates that as a natural result of the competition for market share, airlines are impelled to concentrate their operations, to the extent permitted by the prevailing regulatory process, at an individual airport while serving a given market. These results are derived by analyzing the implications of observed patterns of traveler behavior on the strategy of an individual airline within a given airport, and then extending this argument to the general competitive game involving several airports and several airlines. The results imply that any strategy seeking to develop satellite airports will inherently be frustrated unless the competitive behavior of the airlines is deliberately altered.

Underground pipeline corrosion

Abstract: It has been estimated that losses to the water works industry in the United States due to underground corrosion are in excess of $150,000,000 annually. Work definitions and theory of underground pipeline corrosion are presented. Various methods have been tried in an attempt to combat the effects of corrosion on ferrous metal pipe buried in the ground. Insulating coating supplemented by a cathodic protection has proven to be the most economical and longest term positive corrosion control method yet developed.

Review of car-following theory

Abstract: Steadily increasing volumes of traffic and the accompanying concern for safety have spawned the need for a thorough understanding of the dynamic characteristics of vehicular flow. Car-following theory has been developed as a mathematical description of traffic flow on long, straight highways in dense flow conditions. This theory, consisting of a body of over 30 models, provides a conceptual basis for understanding traffic phenomena, permits analysis of safety considerations, allows a determination of highway capacity, and provides a basis for automatic control of vehicles. A primary intuitive appeal of the car following methodology is this microscopic consideration of the actual factors involved in the driving process. Milestones in the development of car following theory are traced from initial investigations to current studies. Theoretical justifications employed in the development of the better known models are related.

Statewide transportation planning

Abstract: The emerging statewide transportation planning process is described and compared to a typical transportation needs study. The view taken is that the statewide transportation planning process represents the gradual merger of transportation needs studies with the urban transportation planning process. Statewide transportation plans are now being developed for single modes, i.e., highways, considering (1) user as well as nonuser goals; (2) the formulation of alternative systems; (3) analytical models to predict the demand for future travel; and (4) comprehensive evaluation criteria. Also, traditional highway needs studies are being replaced by the National Transportation Planning studies which represent a starting point for estimating total transportation multimodal needs. As experience is gained with a single mode transportation planning studies, emphasis will be expected to shift to multimodal planning.

Schedule Planning and Timetable Construction for Commuter Railroad Operations

Abstract: This paper describes a set of techniques developed to assist in planning the operations of a commuter railroad and similar types of public transportation systems. Computer models are used for generating information and processing data with the planner making the value judgment decisions regarding the degree to which the various objectives are achieved. The method attempts to balance the objectives of the user (travel time and comfort), the system operator (operating cost), and the owner-financier (capital investment). The first portion of the method deals with schedule planning, in which the overall trade offs between quality of service and costs are addressed, and the general plan of operations (such as whether or not to include express service) is developed. Once the general plan has been (tentatively) set, then the detailed construction of a specific timetable, including equipment and crew assignments, is addressed.

Freeway Traffic Control and Surveillance Model

Abstract: The development of on ramp metering control strategies for a freeway can be aided by the well-developed theory of linear optimal control. The recently developed "aggregate variable" model appears to be best suited for this purpose. In this model the freeway is partitioned into lengths of about 1/2 mile and traffic is described in terms of the aggregate variables section speed, section density, and volume. This model and linear optimal control theory are used to developed an on ramp metering strategy which is designed to maintain freeway conditions near nominal conditions in the presence of disturbances. An illustrative design for a segment of the San Diego freeway in Los Angeles is provided. The companion problem of processing freeway sensor data to provide current estimates of the aggregate variables can be approached through standard techniques in estimation theory. Methods of attacking this portion of the freeway surveillance problem are presented.

Hydraulic Elements for USBR Standard Horseshoe Tunnel

Abstract: The hydraulic elements for the USBR standard horseshoe tunnel are identified and computed. These elements are described in relation to the varying value of the central flow depth.

Service and capacity of people mover systems

Abstract: People mover systems are being advocated as solutions to a wide range of urban transportation problems, including internal circulation within activity centers. People movers are most applicable where trip demands are uniform without extreme peaks, and concentrated at definitive node points well beyond acceptable walking distances. This type of trip pattern occurs at most airports and some activity centers but is not common within the typical central business district. Internal trip patterns within CBDs are comprised of many short multipurpose trips with high peaking characteristics and dispersed rather than concentrated desire lines. Trip patterns of this type are best accommodated by walking. Enhancement of pedestrianism within appropriate activity centers, by providing pedestrian only precincts and grade-separated convenience networks are practical and viable alternatives for improving their internal circulation. Many cities are implementing programs of this type.

Parking facility layout: level-of-service approach

Abstract: The primary function of a parking facility is to serve its users in an efficient and convenient manner. The basic objective of this study is to establish a method of measuring parking efficiency of individual facilities, based on the level-of-service concept. It is felt that the approach in this study will standardize the facility service satisfaction to the parker and thus furnish general guidance for the preliminary design and evaluation of parking facilities. In approaching this objective the study identifies and evaluates a group of principal variables which exert significance on parking service provided by parking facilities. The variable investigation indicated that availability and flow/capacity ratio are the most prominent parameters, and therefore, are included in the derived method for designating the level of service of parking facilities. Finally, a feedback analysis is made to balance the design of parking layout considering both quantitative and qualitative factors. This study identifies a group of principal variables influencing the service level provided by a typical parking facility.

Analysis of Passenger Delays at Airport Terminals

Abstract: Although supportive numerical data have not been collected, specific consideration has been given to the operation of Toronto International Airport to show the procedure of analysis in detail. The ...

Computerizing Pipeline Design

Abstract: Computer programs are available that will almost exactly simulate the operation of a water distribution system. Accurate basic data on the existing water distribution system are essential to set up a reliable mathematical model. Extensive field tests are necessary to obtain flows through major trunk mains, coefficients of carrying capacity of the pipelines, consumption rates in the various sections of the system, and to determine water available for fire protection. The most economical design will fully utilize existing facilities to the maximum. The mathematical model must be checked against actual operation of the water system before computerized design of additional pipelines and other facilities are undertaken. Computer print-outs should show all essential input data and the results obtained in a form which makes it a relatively easy task for analyzing by the design engineer. Optimization of cost and complete computerized control of a water system are in the future.

Response of Structures to Combined Blast Effects

Abstract: This paper describes methods of computing dynamic structural response, including interaction between the structure and surrounding soil. Two applications of the finite element method to the dynamic response of a small structure embedded in sand are described. One application involves a three dimensional analysis in which the soil is represented by continuum elements and the structure by plate elements. The second application involves an axisymmetric approximation of the structure, in which the effects of nonlinearity of the soil and slip between soil and structure are accounted for. Comparison is made between the analyses and measurements made during the physical experiment which was conducted at U.S. Army Waterways Experiment Station, Vicksburg, Miss. The main goal of the paper is to assess the capabilities and limitations of existing finite element methods to predict response under these conditions. Satisfactory agreement in the frequency domain between about 40 to 200 cps was obtained. A correlation at higher frequencies was not attempted.

Energy-intensiveness of transportation

Abstract: Historical, present, and possible future patterns of energy consumption in the transportation sector are examined for intercity freight and passenger traffic and for urban passenger traffic. The energy-efficiencies among the various transport modes are quite variable. Airplanes are relatively inefficient; cars and trucks are slightly more efficient; and railroads, waterways, pipelines, mass transit, and buses are quite efficient. The energy implications of changes in modal mix for freight and passenger transport are explored using two hypothetical futures.

Structural model studies of large pipe bifurcation

Abstract: This paper presents the results of a structural model study conducted on the design of a massive 12-ft, 6-in (3.81-m) diam steel pipe bifurcation subjected to a static head of 2,000 ft. (approx 610 m). The prototype structure is the largest bifurcation in the discharge line manifolds in the A.D. Edmonston Pumping Plant in Southern California, which pumps water over the Tehachapi Mountains in a single lift. The use of models in the design procedure is examined. Techniques used in determining the elastic stresses are presented and the results compared with a finite element analysis developed for this problem.

Pricing in mass transportation

Abstract: The purpose of this paper is first, to review briefly the current pricing policy of urban transportation, and the privately operated bus transit company in the Milwaukee area is examined The investigation finds that a lowered bus fare, together with improved service, will substantially increase transit patronage, which will in turn reduce the cost of operating bus transit as a consequence of the existence of the economy of scale The paper examines the characteristics of mass transit users in this country and concludes that the majority of the transit riders are captive riders in the sense that they do not have any choice in their mode of transportation This finding substantiates the hypothesis that mass transit fare should be significantly reduced, not just for attracting automobile users to transit and thus to limit congestion, but also for increased social welfare resulting in improved equity

Flexible pavement evaluation using hertz theory

Abstract: HERTZ'S THEORY OF THE DEFLECTION OF AN ELASTIC PLATE ON A FLUID SUBGRADE, WHICH WAS THE BASIS FOR WESTERGAARD'S ANALYSIS OF CONCRETE PAVEMENTS, IS SHOWN TO BE APPLICABLE TO FLEXIBLE PAVEMENT EVALUATION. GRAPHS ARE PRESENTED ENABLING THE INTERPRETATION OF DEFLECTION BOWL MEASUREMENTS FOR BOTH THE VIBRATORY ROAD RATER AND THE BENKELMAN BEAM IN TERMS OF THE CHARACTERISTIC LENGTH OF THE FLEXIBLE PAVEMENT. THE LOAD REQUIRED TO CAUSE A UNIT DEFLECTION OF THE PAVEMENT SURFACE, REFERRED TO AS PAVEMENT STIFFNESS, IS EXAMINED IN TERMS OF THE SIZE OF THE LOADED AREA, THE PAVEMENT FLEXURAL RIGIDITY, AND THE COEFFICIENT OF SUBGRADE REACTION. THE REQUIRED PAVEMENT STIFFNESS IS SHOWN TO INCREASE FOR MULTIPLE WHEEL GEARS WITH INCREASING PAVEMENT CHARACTERISTIC LENGTH. TEST DATA ARE PRESENTED FOR BOTH CONVENTIONAL FLEXIBLE AND FULL DEPTH ASPHALTIC CONCRETE PAVEMENTS ON CLAY SUBGRADES USING BOTH THE ROAD RATER AND THE BENKELMAN BEAM. /AUTHOR/

Critical tensile strain in asphalt pavements

Abstract: Charts based on two-layer elastic theory are presented for determining the critical tensile strain at the bottom of the asphalt-bound layer under single, dual, and dual-tandem wheels. They can be applied directly to full-depth asphalt pavements where only two layers are involved. For a conventional three-layer system, a method is developed to convert it into an equivalent two-layer system, so that the charts can still apply. A comparison of the critical tensile strains obtained from the charts with those determined directly from a computer program clearly indicates that they are accurate enough for engineering applications. Examples are given to illustrate the use of these charts for determining the critical tensile strains in two-layer and three-layer pavement systems. It is found that for a given pavement type and tire configuration there exists a critical thickness of the asphalt-bound layer at which the greatest tensile strain is obtained, and that the critical tensile strains under dual-tandem wheels are generally smaller than that under the dual wheels alone.

STOL Aircraft Flight and Landing Area Considerations

Abstract: Current research to achieve a technically and socially acceptable short take-off and landing (STOL) aircraft system to help alleviate present air transportation congestion is outlined considering both flight and runway elements. The aerodynamic jet-flap propulsive-lift concept is briefly reviewed with proposed turbofan powered-lift aircraft. Short, single direction, and possibly elevated runways are considered for use in high-land-cost urban areas. Aircraft capability is being developed to enable operations under high crosswind conditions, possibly through the use of crosswind landing gears or crosswind-reducing fences erected along the sides of the runway. Techniques are being developed to insure smooth wind flow over elevated STOL ports, such as on the roofs of buildings; and emergency arresting systems are under study to contain the aircraft on the runway. Heating and grooving of the runway has been explored analytically as a method of keeping the required runway length short by guaranteeing runway friction even under ice and snow conditions.

Pipeline Transportation in the 70s

Abstract: Pipeline history for the petroleum industry is only 108 yr old but the industry has grown into a countrywide transportation system handling approximately 20% of intercity freight. Liquid pipelines are able to handle multiple grades of product without significant mixing, to transport crude oil economically and safely from the oil producing fields to the refineries and refined products from the refineries to centers of population. The pipeline industry is presently faced with political and ecological problems, both real and imaginary. The pipeliners will have to learn to solve these political and ecological problems as they have learned to solve technical problems in the past.

Parameters of Rational Airfield Pavement Design System

Abstract: IN RECENT YEARS THE COMPLEXITY OF THE AIRFIELD PAVEMENT SYSTEM AND ITS ENVIRONMENT HAS RESULTED IN CONTINUED EFFORTS TO UPGRADE DESIGN AND EVALUATION METHODS. TO HELP MEET THE RECOGNIZED NEED FOR MORE EFFICIENT AND COMPREHENSIVE MANAGEMENT OF AIRFIELD PAVEMENT DESIGN, AN AIRFIELD PAVEMENT SYSTEM MODEL, WHICH IS PRESENTED HEREIN, HAS BEEN DEVELOPED. THE AIRFIELD PAVEMENT SYSTEM MODEL INCORPORATES MORE DETAIL, EXPANDS CERTAIN ASPECTS OF THE SYSTEM, AND INCLUDES CONCEPTS RELATING SPECIFICALLY TO AIRFIELD PAVEMENTS. IN ADDITION, THIS PAPER INCLUDES RECOMMENDATIONS REGARDING PARAMETERS WHICH SHOULD BE CONSIDERED IMMEDIATELY IN ANY OPERATIONAL SYSTEM IN ORDER THAT A SIGNIFICANT BEGINNING CAN BE MADE TOWARD ESTABLISHING A TRULY USEFUL AIRFIELD PAVEMENT SYSTEM. A CONCEPTUAL SYSTEMS MODEL WHICH IS ALSO PRESENTED IS THE BASIS FOR SUBSEQUENT WORK AND WILL BE HELPFUL IN DEVELOPING A TRUE "WORKING" SYSTEMS MODEL. AN ATTEMPT IS MADE TO RELATE THE INPUT VARIABLES WITH CURRENT STATE-OF-ART INSTRUMENTATION IN ORDER TO MEASURE PAVEMENT RESPONSE. /AUTHOR/

Investing in regional highway networks

Abstract: A regional, intercity, or statewide plan for ordering priorities for constructing new roads has been developed. This regional highway planning method includes solutions for the traffic generation, distribution, assignment, and road investment problems. A network operator's cost is calculated with the aid of the BPR programs. Construction costs and maintenance costs are given inputs to the system. All monetary costs are discounted to their present worth values. The optimal investment plan provides a network that satisfies the demands placed on it by the travelers and concomitantly minimizes construction costs, network operators' costs, and maintenance costs. The model is capable of handling very large networks (8,170 nodes), a large number of specified construction policies, and a large number of specified alternative network states. The planning method is application oriented.

Reexamination of transportation planning

Abstract: An examination of the factors contributing to transportation controversies is presented. It suggests that unless planners are able to devise a dominant solution in which everyone benefits and essentially no one is adversely affected, it is likely that the planner's recommendations will be controversial. The basic premise of this reexamination is that the planner's obligation is to assist his client communities in achieving a consensus regarding purposeful change. Two conceptual models are examined which suggest that it is necessary to develop a planning process which is more interactive, iterative, and adaptive than current approaches. Six recommendations are presented for refining the transportation planning/evaluation process to enable the planner to assist his client communities in achieving consensus regarding purposeful community change.

Programming Approach to Urban Transit Planning

Abstract: A mathematical programming model based on the objective of maximizing net social benefits is developed to evaluate the effect of introducing a personal rapid transit system into the Minneapolis transit environment The initial solution modeled on the Minneapolis Cordon Count considers the model characteristics of a system consisting of auto, bus, and PRT The assumption that the demand for transit is a given function of transit characteristics underlies the derivation The two characteristics of fare and time per trip are considered Two sets of simulations are conducted The first consists of the analysis of changes in transit demand The second consists of changing the modal service characteristics which involves changing the average trip time The major conclusions are: (1) the introduction of PRT is likely to result in a greater relative reduction of automobile than in bus use; (2) changes in PRT demand and efficiency have small effects on auto and bus use; and (3) reduction in the relative time of a bus trip is likely to be the key to increasing bus utilization

Computer simulation of subway environment

Abstract: A designer-oriented computer program, designated the Single-Track Subway Environment Simulation model, has been developed to simulate multiple train operation in a single-train subway and to provide continuous peak, and average readings for the air velocity, temperature, and humidity throughout the stations, tunnels, and ventilation shafts The program also provides continuous calculations of the location, velocity, and acceleration of the train(s) moving through the system This program is intended for use in evaluating the influence of tunnel geometry, ventilation shaft design, and environmental control equipment upon airflow, temperature, and humidity in a subway The aerodynamic portion of the program has been validated using data from a scale-model test facility

Planning criteria for bikeways

Abstract: Design features reviewed for bikeway design are speed, curvature, grade capabilities, surface requirements, intersections and crossings, signing and cross section dimensions and clearances. Specific cross section criteria for exclusive, restricted and shared bikeways are detailed. The cost of developing bikeway facilities is reviewed. Language: en

Gas Line Response to Earthquakes

Abstract: Since there is no such thing as an earthquake-proof pipeline, gas utilities operating in areas subject to seismic damage need adequate plans to respond to earthquakes. Emergency procedures, organizations, and communications are a must. Desirable design features for pipelines include in-line separator, pipeline drips, pigging ability, filters, and scrubbers. Distribution systems need valving to provide isolation districts and alternate supply. Sharp vertical or lateral dislocations and ruptures of the ground resulting from the February 9, 1971 earthquake caused 450 breaks in the 690 miles of gas piping located in the San Fernando-Sylmar area. Replacements, repairs, and service restorations cost $1,732,000.

New Criterion for Resource Scheduling

Abstract: Resource limitations impose delays in the execution of multiactivity projects. This computer-based experiment investigated both the network configuration and the priorities used at points of obstruction. Reviews of critical path analysis and resource scheduling method are included in addition to a description of the experiment and a summary of the statistical analysis. The effect on delay of network parameters such as free float, density and connectivity is quantified. A new sorting, activity cost per unit time in descending order, is shown to be not significantly less good than traditional critical path values, and of considerably greater practical use on site due to easy computation.

Performance Testing of Freeway Noise Barriers

Abstract: The results of the field evaluation along freeways in metropolitan Toronto show that these barriers are largely ineffective in reducing freeway traffic sound levels at nearby residences. Five different noise barrier types (an earth embankment, normal density and lightweight precast concrete panel walls, an aluminum wall, a plywood wall, and a gabion wall) are described, including materials, appearance, type of support and costs. The barriers, located midway between the houses and the pavement or at the highway shoulder, 60–140 ft (18–43 m) from the nearest houses, provided only 2–6 dba reduction at the first row of houses, 4 ft (1.2 m) above ground. Immediately behind the barriers, where the reductions are of little real benefit, reductions of 8–14 dba were achieved. Calculated reductions due to the barriers were overestimated rather than underestimated.

Roadway capacity related to curb-parking maneuver

Abstract: Of all the factors that hinder the flow of traffic on the roadway, parking is perhaps the most important. In addition to the reduction of roadway width due to providing the parking lane, the most obvious effect of parking is that of the parking maneuver. Accordingly, the objectives of this study were to determine the total vehicle delay and subsequent roadway capacity reductions due to a single curb-parking maneuver. In approaching the objectives, the movements of traffic reacting to a parking maneuver were identified, and procedures were established for determining the delay encountered during a parking movement. The effects of the maneuver on the approaching vehicles were determined in time delay and were applied to the capacity of the roadway, depending upon where the parking maneuver occurred. A computer program was developed and used in example application. The study result indicated that the parking maneuver has a significant effect on the capacity of a section of roadway.