Procedures for the analysis of the shakedown of pavements are developed. The approach employed models the elastoplastic behavior of a horizontally‐layered continuum subjected to repeated moving loads, and permits the incremental process of pavement failure to be considered. Following an examination of the effect of materials and geometry upon the shakedown of a half‐space and a two‐layer continuum, the analysis is applied to the results of a comprehensive road test. It is found that pavement shakedown may be both observed and satisfactorily predicted, and further that the life under traffic of weaker pavements may be conveniently estimated. An outline of a possible design approach utilizing the theory concludes the paper.

Recreational modal split is examined in a study area consisting of two groups of Greek islands, resorts, one in the Central Aegean where available modes are conventional ship and airplane, the other in the Argosaronikos region where conventional ship and hydrofoil operate. Seven established models are calibrated using an aggregate data base. It is shown that the logit model is the most suitable in these circumstances. The calibration technique allows an optimum “value of time” to be determined but the paper questions the validity of this concept in a recreational context. When distances are relatively long (in the Central Aegean) overall travel time is strongly related to mode choice. On the shorter routes in the Argosaronikos region, the most significant variable is service frequency. No significant relationship with direct travel cost is found in either area. A study of the mathematical form in which variables (e.g. time, frequency) enter the model shows that mode choice is best described when the difference of the respective dependent variable between modes relative to its value for the fastest mode is used (ratio form), instead of the more traditional form simply using differences.

Procedures are developed for estimating the parameters required for life‐cycle costing of the elements of maintenance and rehabilitation of concrete bridge decks subject to the deteriorative effects of deicing chemicals. The included elements are the age and extent of deterioration at which annual maintenance can be expected to begin, the rate of increase in annual maintenance, and the age at which rehabilitation is required. The information presented is primarily of use in formulating repair/rehabilitation/replacement policy. The calculated values of the parameters may be expected to vary considerably from observed values of individual bridges, but should reasonably reflect mean values for large numbers of bridges.

A technique is developed to predict bridge accidents. These collisions are complex occurrances influenced by many factors. Previous research found as many as ten items contribute to a structure's potential for collisions. Four years of Texas data (1,000,000 accidents, 29,000 bridges and 100,000 roadway segments) were merged and searched for rural, two‐lane, two‐way bridge accidents. Screening and classification measures were used to purify the data leaving a uniform study sample of 2,849 cases for analysis. The relationship between accidents and predictor variables was investigated by manual, correlation, and regression analyses. The most important variables were: (1) Bridge relative width (bridge minus road); (2) average daily traffic (ADT); and (3) approach roadway width. Regression curves were developed to predict accidents using these factors as independent variables. A probability table was developed to predict accidents. Combinations of approach roadway width and bridge relative width indicate collision rate. Rates may be combined with ADT for particular structures to develop expected accidents per year. The statistical measures for effectiveness were very strong, indicating that the table is a good way to predict bridge accidents.

Modern airport terminal building designs that have finger piers and airbridges sometimes result in significant walking distances for passengers. For a given set of aircraft parking positions next to a passenger terminal building and a given set of aircraft (with associated numbers of arriving and departing passengers), a method to find aircraft stand assignment which minimizes average passenger walking distances is proposed. The method is based on a branchand‐bound technique (backtracking version), slightly modified to accelerate computation. This type of optimization is to be applied only if the number of passengers varies enough between the aircraft in question. The optimum solution mainly affected the number of passengers who walk maximum distances (decreased this number) and minimum distances (increased this number), compared to random aircraft stand assignment.

Requirements for similarity of natural ventilation in wind tunnel models and experimental methods for evaluating its effectiveness are reviewed and tested in a 1:25 wind tunnel model of the Florida Solar Energy Center Passive Cooling Laboratory (PCL). The experiments indicate that, in addition to the requirements for simulation of external flows around the building, an internal Reynolds number based on the maximum velocity and minimum dimension of each room should be larger than $2\times {10}^4\text{.}$ Internal to external velocity ratios are shown to give a detailed unbiased picture of the local internal climate. Dimensionless pressure difference coefficients, based on pressure measurements on the external envelope of the building model, and dimensionless dilution rates, based on tracer concentration decay measurements, can be used to evaluate the relative integral effectiveness of natural ventilation in different configurations. The advantages and limitations of each method, as demonstrated in the study of the PCL model, are reviewed.

Pedestrians walking in corridors tend to maintain a clearance from the walls and any stationary obstacles that they pass, thus, space within corridors is never fully utilized. A number of researchers have, therefore, suggested that an effective width reduction should be subtracted from the gross width to obtain an effective corridor width for design purposes. There are discrepancies, however, in the magnitudes of the effective width reductions that are suggested in the literature.

A proposed definition and method for calculating effective width reductions from pedestrian data is presented. Pedestrian distributions observed in a survey conducted in a pedestrian tunnel at Carleton University, Ottawa, Canada, were used to calculate effective width reductions under various conditions. The reductions calculated for walls ranged between 5.5 in. and 8.7 in. (140 mm and 220 mm). This is less than one‐third of the 18 in. (46 cm) suggested by most researchers. Experimentation with obstacles, such as a waste receptacle adjacent to one wall, resulted in even lower effective width reductions. It is concluded that effective width reductions generally assumed in current design practices are overestimated.

In Japanese expressway systems, congestion occurs on many sections around large urban areas. In order to investigate countermeasures for these bottleneck sections, a traffic simulation model is developed which computes traffic flow characteristics and traces the behavior of congestions under given traffic demands. A 24 km study section was selected from Meishin expressway in Osaka where congestion occurs from two tunnels almost every morning during peak period. An extensive traffic survey was conducted making use of aerial photography, video camera recording and floating tests. A simulation model for traffic flow through bottlenecks was developed on the basis of the results of the traffic survey. The expressway bottleneck simulation model was a macroscopic model based upon the theory of compressible fluid. The results of the simulation model are satisfactory. The output from the model shows that the model pursues the behavior of congested areas and that the travel time through the study section computed from the model output agrees with the actual measurements from the floating test.

A method for optimizing the route structure and schedule for zonal transit services has been extended from one‐dimensional linear cases to two‐dimensional branched networks. The values of zone lengths, subroute lengths, and headways which minimize the sum of operator and user costs are determined by calculus in simple cases and a quasi‐Newton computer algorithm in more complex cases. Algebraic relations are derived which provide useful guidelines for optimal system design and greatly simplify sensitivity analysis. It is shown that user wait costs, user access costs, and vehicle operating costs should be equalized to minimize total costs. A case study is used to demonstrate the applicability of the method. The results confirm theoretical relations and indicate that considerable flexibility exists in adapting transit routes to irregular road networks and demand patterns without substantial cost increases.

A methodology for developing predesign cost estimation functions of transportation systems is developed and applied. The emphasis is on the methodology and the evaluation of the estimation equation, the goodness of which is often taken for granted in most works on the subject. The applications merely serve the purpose of illustrating its applicability. Yet, the predesign cost estimation functions developed, one for highway pavement and another for mass transportation systems, not only illustrate the point but also prove to be useful in estimating the cost of highway pavements and mass transportation systems at the stages of conceptualization or predesign or both. The methodology, when properly used, gives reliable results with few historical data.