This paper develops a method of improving congestion detection in urban motorway traffic surveillance and control systems in Japan. When developing motorway traffic surveillance and control systems, accurate congestion detection is often difficult or impossible because of the disturbances due to the oscillation of congested traffic flow. To improve the accuracy of congestion detection, it is necessary to distinguish noncongested flow from congested flow. Traffic flow data for the Tokyo Expressway and the Keiyo Expressway were collected. Computer experiments were carried out to develop a test to improve the accuracy of congestion detection on urban expressways. Applying the reference value proposed in this study greatly improved the accuracy of congestion detection.

Previous studies have demonstrated a useful relationship between fuel consumption and journey speed, vehicle weight, and idling fuel rate under urban driving conditions. The engine displacement has also been found to be strongly related to vehicle weight. The results of a statistical analysis of these known relationships with published data are presented. The objective is to establish equations for estimating fuel consumption from travel survey data such as journy speed and engine size. Two equations were found to give good estimates of journey fuel consumption. One equation is for urban driving conditions and the other is for steady speed conditions such as in rural and motorway driving. The correlations between the fuel consumptions under the two different driving conditions offer a possibility for developing an empirical equation for journey fuel consumption by taking into consideration the general patterns of travel and journeys.

The flow coefficient for a control valve is an important hydraulic parameter that is used to select and design the controls for a closed conduit system. The parameter is used to determine flow capacities, valve positioning, and energy losses of the system. The coefficient is also used for the analysis of the flow system for other phenomena such as cavitation and transients. It is important to understand the definition of the flow coefficient, how it is used, and how it is determined for a control valve. At present there are two sets of testing standards to determine the flow coefficient for a valve. The standards are different in the definition of how the coefficient is determined and can result in two different sets of flow coefficient data for a valve. Confusion has resulted in identifying which set of standards was used to generate the valve coefficient information, and the importance of designing a system using the same definition of the coefficient.

Pedestrian walking distances in a central business district are mostly dependent on the arrival mode in that central business district and the layout of the transportation network on which these modes operate. Changes to the existing pattern of operations, in terms of the location of new transportation facilities or relocation of existing facilities, can have a significant impact on walking distances. However, often the prime concern has been the impact of these changes on the flow of traffic, with little or no emphasis on the pedestrians. As opposed to arbitrarily derived acceptable walking distances suggested by some researchers, an approach based on findings from a series of surveys conducted in Calgary, Alberta, Canada, is proposed. A set of characteristics that influence the distribution of walking distances is identified. Depending on the form of the distribution, the “critical” distance that would be acceptable to a group of people can be derived using simple calculus. The critical distance will be the distance at which the rate of change of the slope of the frequency distribution of the walking distance for that group of people is greatest. Since the walking distance distributions indicate the propensity to walk, they indirectly represent the actual feelings of the people. This approach also facilitates decisions regarding locations, even where information regarding walking habits is scarce or unavailable. The application of Bayesian statistical decision theory enables one to estimate the appropriate distribution and the critical distance associated with it.

The outline and results of an aerial traffic survey of an 800‐m section of the Hanshin Expressway are described. The objectives of the study were to record congested traffic flow and to determine its causes. Traffic in the study section was photographed by two 35‐mm still cameras every 5 s for 1 h. All vehicles recorded in the southbpund traffic flow were numbered and traced in order to project their trajectories in the time and space diagram. Speed and density contour diagrams were based on the theory of three‐dimensional representation of traffic flow. The characteristics and causes of traffic congestion were analyzed using these diagrams.

Large cities in all parts of the United States are experiencing large development and redevelopment projects in their downtown areas. Regardless of the land‐use activities involved, the maintenance of basic levels of mobility for travel to, from, and within the central business district is crucial to the development's success. Strangely, a systematic advance evaluation of the ability of the transportation system to serve (or survive) the new activity was not common practice until recently. Given the enormous investments involved in these commercial projects, a coherent procedure to determine how well the transportation system will support the venture seems a prudent step. Given the variety of useful tools with which to build this procedure, investors and public officials alike should be able to analyze the situation within a wide range of precision and cost. This paper cites a number of techniques that are “on the shelf,” and illustrates how each component of the downtown transportation system is closely linked with the others. A hypothetical example at an actual location demonstrates several of these points.

Speed (road) bumps are controversial. Despite their effectiveness as a speed deterrent device, the use has not been widespread in the United States. A majority of traffic professionals are strongly opposed to the use of these bumps on public right‐of‐way. Liability and safety remain the primary concerns. The current trend is to use “humps” instead of “bumps” which are flatter.

A set of algebraic equations to determine the design discharge for highway culverts is proposed. The kinematic‐wave theory and the concepts underlying the commonly used rational method are adopted to derive these design discharge equations. Various drainage basin configurations, among which are rectangular and converging catchments, cascades of planes and overland flow‐channel flow systems are considered. Composite basins with nonuniform slopes, roughness properties and runoff coefficients are included. In order to employ the proposed equations, the rainfall intensity‐duration relationships and the physical characteristics of the basin should be specified. Unlike empirical formulas used for the same purpose, the proposed equations are physically based. They can be employed for a variety of drainage situations within the limitations of the kinematic wave theory. A practical application section is included to show the use of the proposed equations.

Priority ranking of pavements for rehabilitation is currently based on benefit‐cost analyses and sufficiency ratings in most states. These methods either neglect social factors or assign them dollar values on a linear scale. Such methods rely heavily on subjective judgments, which can vary widely, and lack a mechanism to accommodate road users' preferences. Utility theory provides a decision‐making method that optimizes the decision maker's utility or satisfaction, and can convert unquantifiable factors or attributes, such as safety, quality of service, etc., into terms of utility on a zero‐to‐one scale. The procedure for using multi‐attribute utility in decision making is explained and illustrated in an example. The example shows that utility theory can be used satisfactorily in pavement rehabilitation decisions. Some weaknesses of utility theory are also pointed out.

An information‐theoretic statistical procedure for the analysis of categorical or qualitative variables or count data not necessarily arrayed in a multi‐way cross‐classification or contingency table is presented. This procedure can be used to provide a uniform approach to both statistical testing and estimation in various kinds of traffic studies. In particular, a statistical procedure is presented for analyzing counts of violations observed at various intersections during cycles of red left turn arrow or red ball signals. Data was collected at fifteen intersections of different types at different times of the day and located in different geographical locations.