The benefits of constructing grade separations at four railroad crossings in Thunder Bay, Canada, are evaluated. The purpose of the study is to determine the two crossings whose grade separations provide the most efficient traffic operations and maximum accessibility of emergency services (fire stations and hospitals). Efficiency is evaluated by several measures of performance including travel time, delay, and fuel consumption. Accessibility is evaluated by the travel time between the emergency services locations and various areas in the city. Traffic volume data were collected in May 1985 during the afternoon peak period (4:30–5:30 P.M.) for 15‐minute intervals. These data, along with other data related to land uses, are used to establish the origindestination (O‐D) demands through the use of a recently developed model, LINKOD. These O‐D demands and the characteristics of the network represent the basic input to a traffic management model, CORCONF. The CORCONF model is used to evaluate the impacts of various grade‐separation alternatives on both efficiency and accessibility. In addition to analyzing a real‐world problem, this paper also discusses some aspects related to the application of the models described herein, which should prove useful for potential users of the models.

Current transportation planning requires a better understanding of the mode choice behavior of intercity passengers in the short‐haul market. Considerable work has been completed on the topic for the medium and long‐haul ranges, but a limited body of literature is addressed to the problem relative to the short‐haul market. In this study, an attempt has been made to construct behavioral models incorporating modal level of service attributes. An aggregate and a disaggregate mode choice model are formulated based on the logit function. Using linear and nonlinear regression for the calibration of the aggregate model, and the maximum likelihood estimation method for the disaggregate model, the formulations are tested for reliability and validity by comparing them with other published research findings. The model specification is found to be acceptable. For the data base used in this research, the log‐linear model produced better results. The method has been used to analyze the desirable strategy of local air services and to evaluate the sensitivity of the automobile user to highway conditions and highway tolls.

The development of the PASSER II‐84 microcomputer environment system is summarized. It was designed in research conducted jointly by the Texas Transportation Institute (TTI) and the Texas Department of Highways and Public Transportation (SDHPT) in cooperation with the U.S. Department of Transportation, Federal Highway Administration (FHWA). Significant enhancements were made so traffic engineers at virtually any location could analyze traffic operation problems efficiently. The study combined microcomputer technology and newest PASSER II‐84 for traffic engineering applications. This maximizes progression and reduces delay, stops, and fuel consumption in optimizing arterial operations. A PASSER II‐84 microcomputer environment system was developed for MS DOS‐ and PC DOS‐based microcomputers. Program documentation and revised input and output management programs were also implemented in this system.

Spangler's equation and Watkins' formula, when used in the current form for very flexible pipes, give poor results. Modifications are necessary to extend their use to very flexible plastic pipes. Simple modifications, based on results from soil‐pipe interaction finite element analyses of very flexible pipes are used to predict the vertical deflection and pipe wall strain. The finite element results are also compared with field data. The effects of deflection factor, deformation factor, pipe dimensions, backfill height, and soil type on the performance of buried very flexible pipes are given. The new design equations would be of great benefit to praticing pipe design engineers.

This paper reviews urban transportation planning in the United States since passage of the Federal‐Aid Highway Act of 1962. That act created the federal mandate for a continuing, comprehensive urban transportation planning process to be carried out cooperatively by state and local governments. The paper traces urban transportation planning from its rise in the 1960s, through the period of the 1970s when planning processes had to deal with greater requirements and complexity, to the 1980s when there was a shift to decentralization of decisionmaking authority from the federal government to state and local governments and the private sector. Planning processes have become more complex and sophisticated but have retained many of the earlier elements and objectives. The evolution is still continuing with the objective of improving procedures and institutions that are adapted to the needs and concerns of today's planners, citizens, and decision‐makers.

One of the large analyses in this country of the need for sound absorptive treatment on highway noise barriers was conducted on the Interstate 440 project in Nashville, Tennessee. Special considerations had to be made of potential multiple reflections problems between noise barriers on both sides of the highway, and between vertical rock faces in deep‐cut sections. This paper presents a detailed discussion of the analysis process and the resultant design of nearly 1/2 mile of sound absorptive barriers. The purpose is to provide information to noise analysts on potential analysis techniques and on problems and pitfalls that may occur. The use of one analysis tool, a computer program developed at Vanderbilt University, will also be described briefly.

The left-turn adjustment factor, as introduced in the 1985 Highway Capacity Manual, for opposed left-turns at a signalized intersection is discussed. The special case involving an exclusive left-turn lane without a separate phase is examined. It is shown that the procedure presented in the manual can be significantly simplified for this situation. A comparison between the left-turn adjustment factor from the new manual and from the procedures of the Interim Materials on Highway Capacity (1980) is presented.