This report is issued by the Task Committee on Freight Pipelines, Pipeline Division, ASCE. Freight pipelines of various types (including slurry pipeline, pneumatic pipeline, and capsule pipeline) have been used throughout the world for over a century for transporting solid and sometimes even package products. Recent advancements in pipeline technology, aided by advanced computer control systems and trenchless technologies, have greatly facilitated the transportation of solids by pipelines. Today, in many situations, freight pipelines are not only the most economical and practical means for transporting solids, they are also the most reliable, safest, and most environmentally friendly transportation mode. Increased use of underground pipelines to transport freight is anticipated in the future, especially as the technology continues to improve and surface transportation modes such as highways become more congested. This paper describes the state of the art and expected future uses of various types of freight pipelines. Obstacles hindering the development and use of the most advanced freight pipeline systems, such as the pneumatic capsule pipeline for interstate transport of freight, are discussed.

The asphaltic plug joint (APJ) is commonly used to accommodate structural movement in motorway bridges. Despite its widespread popularity, the performance of this jointing system is unpredictable, and premature failure is common. A brief description of the standard APJ system currently employed is given, together with proposed alternative joint geometries to improve the in-service performance of APJs. The finite element (FE) code ANSYS v5.1 was used to complete a pilot study of the performance of the APJ system, where models of the standard and of two geometrically altered designs of joint plug (trapezoidal and sinusoidal) were examined. A compression test conforming to ASTM D1074-96 of an APJ sample ensured that measured values of the stress-strain curve were used in numerical analysis. Different structural loading conditions were simulated, and a simplified method to model the interaction between a moving truck wheel and the plug was used to approximate vehicle loading. The results, presented in the form of plots of the distribution and magnitudes of internal stresses, and graphs of maximum stresses at key locations, provide a basis for the study of joint response as a function of plug geometry.

The response of a G4(1S) strong post steel w-beam guardrail system to pendulum impacts has been investigated in a series of full-size physical tests and in simulated experiments using the explicit finite-element analysis code DYNA3D. The physical tests were conducted at the Federal Outdoor Impact Laboratory at the Turner Fairbank Highway Research Center of the Federal Highway Administration in McLean, Va. In the pendulum tests, an 880-kg mass was used to strike the rail perpendicular to its face. The rail section was attached to steel posts and blockouts and supported in a specially designed fixture. Initial velocities of the pendulum at impact were 9.25, 20, 30, and 35 km/h. Acceleration, force, velocity, and displacement histories of the impact event were obtained from accelerometer data taken during the testing. Data from the DYNA3D simulations of the impact tests compared well with the data obtained from the full-scale testing. Displacement plots of the deformed shapes of the rails at 25-ms intervals compared favorably with high-speed film images. Force versus displacement histories showed good agreement with those obtained from quasi-static experiments. The use of pendulum impact tests for screening and evaluation of alternative guardrail systems is recommended.

A Policy on Geometric Design of Highways and Streets, by the American Association of State Highway and Transportation Officials (AASHTO), exhibited severe disparities between its recommended procedures for the computation of braking distances on grades and the design controls of vertical curves. The braking distances it advocated for the design of vertical curves are fully consistent with flat terrains. The grades of the tangents only influenced the curvatures needed to achieve braking distances and thus stopping sight distances on flat grades. A vehicle traveling on a crest vertical curve of Type II, or a sag vertical curve of Type IV, experienced at no time a flat grade. Types II and IV vertical curves join tangents with identical grade orientations. This study pinpoints the inconsistencies of the previous procedures and proposes conciliatory procedures. A new methodology computes simultaneously the worst grades of braking initiation, the associated braking and stopping sight distances, and the resulting minimum rates of vertical curvature. The new methodology can result in longer and flatter curves than currently utilized given the design parameters recommended by AASHTO. The writers recommend the calibration of design parameters of vertical curves for the new methodology prior to implementation and guard against the blind acceptance of longer vertical curves. The inconsistencies by AASHTO may have misrepresented various design parameters.

In the present study a simple methodology is developed, by which the values of available sight distance, for any driver location on crest vertical curves (CVCs), can be precisely and directly calculated. This methodology allows the quick drawing of graphs depicting the changes in available stopping-sight distance (SSD_avail), as well as in passing sight distance, during vehicle movement along a CVC. The length of highway segment with stopping-sight distance (SSD) restrictions is estimated by means of a sight-distance profile. It is shown that crash speed, defined as the speed at which the vehicle is expected to collide with a stationary object on a CVC having restricted SSD, may be used as a measure of the severity of SSD restriction. A combination of the criteria of length of sight-distance restriction and crash speed is proposed as an improved means for evaluating existing or planned CVCs.

The American Association of State Highway and Transportation Officials (AASHTO) presents general controls for the combination of horizontal and vertical alignments. Excellence in alignment coordination enhances safety, operation, and appearance. This paper quantifies one of the AASHTO general controls that is related to introducing a horizontal curve at or near the top of a crest vertical curve. It establishes the locations where a horizontal curve should not start in relation to a vertical curve because the available sight distance is less than (1) the stopping-sight distance (SSD); or (2) the preview sight distance (PVSD) that allows the driver to detect the horizontal curve and react properly and comfortably. The range of these locations, called the “red zone,” is established for a selected alignment using three-dimensional (3D) analysis of sight distance. Both daytime and nighttime cases are discussed. The sensitivity of the red zones for PVSD to the superelevation rate, turning direction of horizontal curve, vertical curvature, and spiral curves is examined. The effect of spiral curves and location of cut slopes on the red zone for daytime SSD is also examined. This paper shows how 3D analysis can be used to identify red zones for existing combined alignments or to avoid them for new alignments. As such, it should be of interest to the design engineers concerned with highway safety.

For permitted left turns at signalized intersections from exclusive or shared lane groups with multiple opposing lanes, this paper proposes modifications to the delay equation used in the 1994 Highway Capacity Manual (HCM). In the 1994 HCM, the green time for left turns is reduced by the opposing queue clearance time in the worksheet calculation of a left-turn adjustment factor that reduces the saturation flow rate of the left-turn lane group. A difficulty with the 1994 HCM is that it uses this saturation flow rate in a delay equation that allows vehicles to make “slow” left turns from the instant the green time begins. These vehicles actually make “no” left turns until the opposing traffic is less saturated, and then make “faster” left turns as acceptable gaps allow. This modified delay always exceeds the 1994 HCM delay for exclusive left-turn lanes (by more than 50% over total delay in some cases) but may either increase or decrease the HCM delay for shared lanes. Both delays are compared over a range of volumes for one example from the 1994 HCM.

Advanced Traveler Information Systems (ATIS) have the potential to mitigate freeway congestion. The success of ATIS depends to a great extent on understanding drivers' route switching behavior. This route diversion behavior is a complex process that depends on situational constraints, socioeconomic characteristics of motorists, and latent individual characteristics. Three latent factors, namely risk acceptance, trust in traffic information provided, and expectation level of quality of information provided, were identified in this study. These latent factors, as well as socioeconomic characteristics and situational constraints, were incorporated in a binary logit model of stated route diversion intentions. It is observed that the latent factors were statistically significant explanatory variables of the drivers' stated route diversion intentions.

Urban bus route network design involves determining a route configuration with a set of transit routes and associated frequencies that achieves the desired objective. This can be formulated as an optimization problem of minimizing the overall cost (both the user's and the operator's) incurred. In this paper, the use of genetic algorithms (GAs), a search and optimization method based on natural genetics and selection, in solving the route network design problem is reported. The design is done in two phases. First, a set of candidate routes competing for the optimum solution is generated. Second, the optimum set is selected using a GA. The GA is solved by adopting the usual fixed string length coding scheme along with a new variable string length coding proposed in this study. The former assumes a solution route set size, and tries to find that many best routes from the candidate route set, using a GA. The route set size is varied iteratively to find the optimum solution. In the newly proposed variable string length coding method, the solution route set size and the set of solution routes are found simultaneously. The model is applied to a case study network, and results are presented.

Origin-destination (O-D) trip matrix estimation from traffic count surveys is regarded as the most economical and effective methodology in road network analysis for transport planning and traffic management. Despite the numerous mathematical estimation techniques previously developed, the fundamental procedure of selecting count locations itself is a prime determinant in the quality of the ultimate estimation and deserves more in-depth exploration. In this paper, some existing methods being adopted in practice are reviewed. Two basic rules are established based on previous works and are formulated in a linear programming model to determine the best survey locations for O-D estimation. However, technical problems will be incurred when applied to a large network with huge number of variables involved. The proposed maximal O-D selection method is proved to provide results with a comparable level of reliability, and a sensitivity test is conducted with different objective functions to verify this proposed strategic algorithm. This paper examines the efficiency of additional link counts for O-D estimation and recommends an efficient data collection method. The models and algorithms are illustrated with numerical examples.

Proponent mitigated development (PMD) strategies are used in the planning stages of new development to bring about compatibility between noise sensitive land uses and transportation noise. Development can be a transportation project initiated by a transportation agency or it can be a noise sensitive land use initiated by a private developer. In either case, the proponent of the development bears the responsibility for mitigation of transportation noise to bring about noise and land use compatibility. Noise and land use compatibility programs that make use of proponent mitigated development strategies were studied to identify critical program elements, measures of effectiveness, and the steps to be taken for program implementation. It was found that proponent mitigated development strategies can be an effective complement to land use zoning in traffic noise and land use compatibility programs. Further, administrators of existing programs report minimal maintenance costs to planning agencies, and suggest that these programs promote a fair distribution of noise abatement costs.

This note presents, for the first time, the concept of benchmarking of airports from the perspective of designers and planners. Benchmarking is valuable for three reasons: it provides basic data otherwise difficult to obtain, it defines world class standards for facilities, and it identifies priorities for improving the physical design at individual airports. Effective benchmarking is focused on objective data of capacity or performance that can be measured and observed in widely different operations, rather than on data that is subjective or derived from widely different accounting practices. The note illustrates the approach by comparing availability of airside and landside facilities at comparable major airports worldwide—those that handle between 12 and 26 million passengers each year, and for which data were available. This initial comparison underlines the fact that airports worldwide differ enormously in the relative amount of facilities they provide, and suggests which airports might require additional investments to reach the best worldwide levels. An application of benchmarking to the México City International Airport demonstrates the usefulness of the concept.