Two major factors involved in the selection of an alinement for a highway are addressed. The first is the identification of those environmental concerns that should be considered in the alinement selection phase; and secondly, the development of a methodology for the incorporation of the environmental factors into the alinement assessment task. The environmental concerns were grouped into two categories: (1) Physical environment; and (2) social environment. Included in the physical environment category were these factors: Water regime, erodibility, woodlands, unique ecological areas, wildlife, and agricultural. The social environment category contained the factors: Land development, noise, utilities, recreation, unique cultural features, and aesthetics/scenery. A number of techniques capable of allowing the environmental concerns or factors to be incorporated into the alinement assessment task were investigated. The method recommended for use by location engineers was an overlay technique utilizing a computer program package containing a map plotting routine.

This study provides information to state‐level planners for rational decision‐making regarding the enhancement of the analytical process for setting highway improvement priorities. Arizona's analytical procedure, a sufficiency rating scheme typically used by many states, is reviewed in light of the current problems facing decision‐makers. Four computerized alternative analytical techniques representing the state‐of‐the‐art are also reviewed. Sufficiency rating techniques are found to supply inadequate information regarding project benefits and the attainment of the improvement program objectives. Also, sufficiency ratings and utility functions are considered technically unsupportable because of their subjective base. Option‐evaluation techniques are found to supply valuable information regarding the user benefits generated by highway improvements. However, these techniques are limited in their scope of application and cannot incorporate all of the various project types or program goals into the improvement priority process. What is needed is a method which can evaluate the trade‐offs between various types of improvement projects on a comprehensive objective basis and evaluate improvement priorities against the multiple constraints and objectives which exist.

The current state‐of‐the‐art and current practices followed for pedestrian accommodation in highway work zones, and suggested guidelines to improve pedestrian safety is briefly described. Literature searches revealed only a broad and sporadic reference and guidance for pedestrian accommodation in work zones. Field investigation of work sites revealed either lack of, or inadequate accommodation of, pedestrians in work zones. The guidelines developed for accommodating pedestrians in work zones include: (1) The conditions under which pedestrian accommodation should be provided; (2) minimum pathway width requirements; (3) pathway types; (4) pathway delineation and protection; (5) pathway surface; and (6) motorist and pedestrian informational needs to guide them through and around a work zone in a safe manner.

Absorption characteristics of cylindrical soil aggregates manufactured using three soils of different mineralogy and composition and fired to temperatures between 1,922° F (1,050 °C) and 2,282° F (1,250 °C) were assessed with respect to absorption of water and of bitumen. The investigation revealed that the commonly used 24‐hr water absorption value is not a reliable indicator of the absorption capacity or the bitumen absorption potential of aggregates. A 5‐hr boiling test is suggested to determine the absorption capacity. Absorption of bitumen by the manufactured aggregates shows a good correlation with the porosity if pores larger than 0.05 μm in radius are considered. Mercury porosimetry is found to be a suitable technique for determining the pore size distribution of aggregates and the data may be used to predict the absorption characteristics of aggregates.

The effectiveness of roadside safety appurtenances under impact with minisized automobiles is investigated. The vast majority of existing roadside hardware have been qualified under guidelines which have not considered vehicles in this light weight range. Since the numbers of these minisized vehicles are increasing dramatically with this trend expected to continue, the potential problem areas are significant. They are shown to include excessive occupant‐vehicle interior velocities and ridedown accelerations along with vehicle dynamic instabilities. It is demonstrated that mini‐cars are much more susceptible than full‐sized automobiles to these unstable modes of behavior when subjected to eccentric impact loading. The prospects for improving existing highway appurtenances and developing new families of these devices to more effectively meet new FHWA guidelines are examined. Considerations of cost, site dimensions, variation in vehicle size, shape, and weight, and their individual effects on crash cushion performance and design are discussed.

Several recent papers have discussed the shortcomings of a simple approach for determining traffic signal settings over a network. This procedure iteratively sets signal timings at each intersection to minimize delay, holding flows constant. Flows are then adjusted to a new user equilibrium, and the process is repeated until both flows are at equilibrium and signal timings are optimal given the flows. This paper reviews the shortcomings of this procedure and describes an algorithm for small networks which overcomes these shortcomings. This new algorithm is used to quantify the errors in the simpler approach. Also, conditions under which both procedures would produce the same solution are discussed.

Harnessing is a technique of resisting thrust in pipe bends where it is judged to be a more economic alternative than casting anchor blocks, or where the ground in which pipe is buried is weak or unstable and, thus, is incapable of economically providing passive pressure necessary for thrust blocks. Some erroneous technical papers have been in circulation which have influenced design in some circles to the economic detriment of the projects involved. This paper refutes formulas often used to calculate the tensile force in the first joint at bends in pressure pipelines where Jhrust is resisted by restrained or harnessed joints.

A rationalized method utilizing the theory of wave refraction and soil liquefaction is presented for the analysis and design of a pipeline shoreapproach. The bending of wave train due to bottom contours near shore and the liquefaction of marine soil during storm conditions are addressed as the basis of the pipeline stability analysis. Major decisions regarding pipe burial, installation method, weight coating, construction scheduling and cost effectiveness are closely related to the final design of the pipeline.

A statistical analysis is presented of the length in time of the vehicle change interval, i.e., the sum of the yellow and all red times, for an approach to a signalized intersection. The analysis is based on a widely utilized equation for computing the required length of time of the vehicle change interval. Vehicle speed on the approach to the intersection is found, surprisingly, to make a negligible contribution to the variance of this time, while vehicle deceleration is found to be very important. The results of the statistical analysis reveal that the application of the standard equation for the length of the vehicle change interval by the traffic engineer is misleading in terms of the traffic situation it truly represents.