A study of the relationship between pavement performance and routine maintenance is presented. A concept for deriving this relationship is described. This concept introduces two parameters to represent quantitatively pavement performance and level of pavement routine maintenance. An application of the concept is illustrated by means of a case study based upon the data of the state highway system of Indiana. Statistical correlation and regression analyses were performed to examine the relationship between the two quantitative parameters. A total of seventy‐five highway routes were analyzed. These included six rigid pavement, ten overlay pavement and fifty‐nine flexible pavement routes.

An experimental study of the interaction of soil and buried pipes was carried out with a view to improve underground pipeline design. Six pipes of different rigidities were tested in a large soil box. Radial deflections and tangential strains in the pipe wall were measured at different loads and laying conditions. Nondimensional deflections and ring bending moments were calculated for a wide range of pipe‐soil stiffness ratios. Simple expressions for short‐term behavior of buried pipes are presented.

A microcomputer‐based railroad capacity analysis model is described which allows for interactive use. Train dynamics are calculated in a simplified way and the computer program displays the space‐time trajectories of individual trains continuously, allows the user to stop the simulation and to override the meet, and overtake decisions taken by the computer program. The results obtained with this simplified model for a heavily traveled section of the Canadian National mainline in the mountain region of Western Canada are compared with the results obtained from a state‐of‐the‐art mainframe computer model. It is concluded that the simplified model provides accurate results and that its interactive features offer a useful planning tool for the rapid preliminary analyses of railroad capacity problems.

This paper presents an overview of current management techniques that are aimed at improving the efficiency and productivity of urban freeways. The major topics that are addressed include capacity management techniques (entrance ramp control, mainline control, corridor control, and priority control); demand management techniques (peak‐period dispersion, ridesharing, and improving public transit); and techniques of managing nonrecurrent congestion (traffic surveillance systems, servicing, and motorist information systems).

Pavement management systems usually focus on life‐cycle cost as the most important criterion for selecting the optimal pavement strategy at the project level. Pavement management decisions, however, are made in the context of multiple and often conflicting objectives of users, operators, and highway agencies. This paper presents an integrated model for project‐level pavement management, which consists of a life cycle cost model and a costeffectiveness method. The life cycle cost model generates the feasible pavement strategies for a given highway segment and provides the design, performance characteristics, and various costs for each. The cost‐effectiveness method performs an evaluation, which leads to the identification of the optimal strategies. Analysis results of the proposed approach indicate that when the evaluation of pavement strategies explicitly recognizes the multiple types of costs as well as measures of pavement performance, life cycle cost affects the ranking of the strategies, but the optimal choice is often not that of minimum life cycle cost.

The initial states of stress and deformation of a buried flexible pipe with unsupported haunches are calculated modeling the buried pipe as a cylindrical shell supported on an elastic foundation with nonuniform stiffness. The deformed pipe is then subjected to internal pressure and the changes in the states of stress and deformation are computed. The results obtained through numerical integration of the differential equations governing the nonlinear behavior of the buried pipe show that the invert of a flexible pressure pipe with unsupported haunches flattens and flexural strains develop at the invert. Furthermore, the flattening at the invert increases the hoop strain in the pipe resulting from the internal pressure. Implications of these strains on design and installation of flexible pipe are studied.

Coordinated timing plans may be developed for actuated signal systems but all existing optimization methods require that each actuated signal be converted to its nearest equivalent pretimed unit. Using bandwidth maximization as a starting point, a new procedure is developed that specifically accounts for actuated timing flexibility. Yield points and force offs at non‐critical signals are adjusted so they just touch the edges of the through‐band while critical signals are unmodified. This method is applied to a data set describing midday traffic conditions on an urban arterial system of six signals in central Illinois. Simulation is used to evaluate these timing plans and compare them with corresponding pretimed alternatives.

The tradition of selecting the 30th highest hourly volume or what is known as the ``knee-of-curve'' approach for road design is based mainly on the facility utilization because it permits a given road facility to be congested for a certain number of hours during the year. This note reexamines the design hour volume concept from the users' perspective. Alberta's highway system is investigated and the users' perspective is considered by classifying the road sites into several types according to trip characteristics, such as trip purpose and trip length distribution. The main conclusions of the study are as follows: (1) the type of road use is a significant variable that should be considered for appropriate design hour volume; and (2) to provide a more uniform service to the users of various road facilities, it is better to use different highest volume hours for designing different types of roads.

A road network system is perhaps one of the most important necessities for the economic development of developing countries. In this paper, the result of the case studies of over 20 years' data of the Nigerian situation is studied. This is compared to the maintenance expenditure in the World Bank Report and the British maintenance figure. Based on the analysis of the foregoing, the value of U.S. $1,160 (N800) per kilometer per year would appear a reasonable value to be used for annual maintenance per kilometer in a developing economy without the inflationary pressure of an oil economy.