Environmental analysis of transportation systems is a comprehensive and demanding task. The environmental planner is required to carefully and objectively examine project data provided by transportation planners and designers, review existing environmental laws and regulations that may affect the project, make appropriate calculations of impact, compare impact values against acceptable criteria, and recommend mitigation where needed. An outline of the procedures followed and the issues addressed during such an analysis are presented in this paper, which is one in a series by members of the Urban Transportation Division's Committee on Transportation Planning. The series of articles is designed to provide guidance on a variety of planning concerns. Discussion in this article is limited to the transportation modes of highways and airports. The impact areas of noise analysis, air quality, and water resources are covered, reflecting the engineering‐related issues of the environmental questions that generally concern civil engineers. The paper is not intended to discuss the integrated process for environmental consideration in a manner that would be found in a policy white paper; rather, it presents an overview of appropriate laws, regulations, and prediction models.

There is some lack of uniformity in determining earthworks overhaul distance. Often, it is calculated as the distance between the centers of gravity of the cut and the fill, less the freehaul distance. This paper describes a different approach for calculating the haulage distance, i.e., to use the distance between centers of gravity of the cut and fill as the actual hauling distance to be paid for. It is proposed that the correct procedure should use the entire distance over which the earth volume is moved. Four basic reasons for this suggested approach are presented and discussed.

Turning traffic volume data gathered manually at four intersections have been studied to determine if either Fratar, Furness, or Kruithof models could be used to design labor‐saving strategies for manual counts of traffic flows at road junctions and to detect observation errors in a given data set. Each model was used to recompute the observed turning volumes by using different abstractions of the original data as model inputs. The standard errors obtained correlate partly with the level of traffic flow and the magnitude of error‐inducing features at the observation sites. The results indicate that the models could be applied to obtain an indication of the magnitudes of observation errors in given data sets. It is also demonstrated that the models can be used to design a labor‐saving observation strategy for T‐intersections in all cases and for fourlegged intersections when reliable historical data exist. The Kruithof model was found to give the least errors, and it generally entails the fewest calculations.

The practice of evaluating consistency in geometric design is addressed. The current practice is based on comparing the speed of a certain percentile value at the points of interest. The underlying reasoning is to control the amount of speed change incurred by the drivers. This paper shows that comparing the two speed distributions does not give the full picture of all the speed changes that the drivers incur. In the extreme case, it is argued that, theoretically, even when the two distributions are identical, it is still possible that each driver will experience a speed change. Hence, it is proposed to obtain and analyze the distribution of the speed differences. Using an empirical example, it is shown that the current approach is likely to underestimate the amount of the speed changes, and hence, the current approach is prone to accept inconsistent designs as consistent.

The development of a computer program for the analysis of axisymmetric slabs of finite extent supported by an elastic solid foundation is described. CFES employs the method of concordant deflections and is much less taxing on computer resources than corresponding finite element programs. It is shown to be a useful tool in the analysis of rigid pavements, especially in investigating subgrade stress distributions, where it can aid interpretation of finite element results. Other possible applications include analysis of foundation rafts and footings, floor slabs, etc.

Microcomputers and associated software are providing tremendous opportunities for the public works engineer in the analysis and evaluation of transportation projects. In particular, a wealth of software is available for evaluating urban arterial improvements in both the long term and the short term, and in establishing project priorities. Microcomputer software exists for project‐level traffic forecasting, traffic operations project analysis, and the prioritization of projects. For project‐level traffic forecasting, a microcomputer package, simplified project forecasting (SPF), provides a cost‐effective procedure for determining future traffic estimates on urban arterials. Several packages exist for traffic operations project analysis. These include: signal operation analysis package (SOAP‐84); progression analysis and signal system evaluation routine (PASSER); highway capacity manual—signalized and unsignalized intersections; and queue work zone (QUEWZ) impacts. The needs inventory system (NIS) provides a useful package for identifying deficient arterials and prioritizing candidate improvement projects. These packages greatly enhance the ability of the public works engineer to evaluate urban arterial projects.

A questionnaire is distributed to licensed drivers in Iowa, asking questions regarding assignment of right‐of‐way at uncontrolled T intersections. A majority of respondents gives incorrect answers. Age is determined to be related to correctness of response, with older drivers having a greater proportion of correct responses than younger drivers. Traffic and accident data are collected for randomly selected uncontrolled T and four‐legged intersections. The accident rates calculated for these intersections are 0.251 and 0.733 accidents per million entering vehicles, respectively. The difference in the rates is found to be significant at the 0.005 level. It is concluded that a difference exists between drivers' perception and legal right‐of‐way assignment at uncontrolled T intersections. A recommendation is made to change the law in Iowa to give the right‐of‐way at uncontrolled T intersections to vehicles on the nonterminating roadway, and for research on nationwide uniformity in the laws governing T intersection right‐of‐way and possible revision of the Uniform Vehicle Code.

Pipelines are subjected to variable support conditions in the longitudinal direction. These support conditions are encountered due to the variation in bedding and soil properties along the pipe, the geometry of the pipeline, and the different installation schemes. Pipelines are also subjected to a variety of load combinations in the longitudinal direction. A study of these loads and support conditions and their effect on the performance of reinforced plastic mortar (RPM) pipe is made. A structural model used to calculate the longitudinal stresses on the pipe wall is presented. Composite laminate analyses are performed on RPM pipe wall with stress resultants from different load combinations. It is found that the allowable strains are exceeded when the pipe wall is analyzed as a composite structure. In some installation conditions, the strains in the longitudinal direction prove to be more critical than the strains in the circumferential direction. It is recognized that the design of the fiberglass reinforcement in the circumferential and longitudinal directions and the fabrication of wall laminas could be improved if an elaborate analysis procedure, like the one proposed in this study, is adopted.