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In heavy traffic flow conditions, vehicles have limited manouverability which affects the magnitude of response to incident-induced traffic disturbances and how fast changes in these traffic variables can signal the occurrence of an incident. Such characteristics are usually used to formulate a loop-based algorithm. A recent study reported that some existing algorithms were not able to maintain a desired level of effectiveness when these algorithms were used to detect incidents with a video-based detector system. Two new video-based automatic incident detection algorithms, the INdividual Detection Evaluation (INDE) and COmbined Detection Evaluation (CODE) algorithms were, therefore, developed for the detection of lane-blocking incidents in heavy traffic flow conditions using the Central Expressway in Singapore as a case study. The algorithms detect incident-induced traffic speed and occupancy disturbances differently: INDE processes information at each individual detector station and CODE processes inform...

Globalisation has generated more shipping traffic and congestion at some seaports. The sea space capacity of a port is important to planning and operation. To assist in port planning, we present a decision support system. It has an interactive interface to facilitate entry and editing of data which include information for developing a sea space network, operational procedures, traffic pattern, etc. The system estimates the capacities of various port facilities and the entire sea space. By loading a traffic pattern onto the network, bottlenecks within the port waters can be identified. One can use it to assess the effectiveness of congestion management measures, and to study the impacts of planning concepts, operational procedures, etc. The logic and structure of the system are generic and can be applied to any sea space.

Sea space planning and congestion management is receiving more attention. However, little work on sea space capacity and strategy analyses can be found in the literature. Compared to other transportation systems, a sea space system has some special features that require consideration. The system capacity also depends on the pattern of traffic using the system. In this paper, we model a sea space as a directional network and capacity models for berthing areas, anchorage areas, fairways and their intersections, as well as the entire sea space system are developed. These models can be used to compute capacity for any given traffic pattern which can be extracted from vessel trip records or from traffic forecasts. To implement these models, a software system called Sea Space Capacity and Strategy Analysis System (SCSAS) has been developed in Visual C + + and is now being used in Singapore.

Energy costs and availability are major concerns in most parts of the world. Various measures to reduce energy consumption have been proposed. This paper focuses on two strategies to control aircraft ground operations as fuel conservation measures: operating fewer engines while taxiing, and towing aircraft between terminal area and runways. The potential benefits, costs, safety and operational issues related to implementation are investigated. As an illustration, the implementation of these strategies at ten major US airports is analyzed. About 278 million liters of jet fuel could potentially be saved from aircraft towing at these airports at their 1987 operation levels. However, there are some concerns related to towing which would make implementation unlikely until there is more urgency in fuel conservation. A more readily implementable strategy would be operating fewer engines while taxiing. About 88 million liters of fuel could potentially be conserved at these airports at 1987 operation levels.

The movement of aircraft in the terminal airspace is simulated using a fast‐time, critical events model. The model tracks the flight of each aircraft within the airspace studied and estimates aircraft delays within the terminal airspace. It also provides other relevant statistics such as controller workload, flow rates and travel times. The airspace model is capable of simulating a multi‐airport, multi‐sector environment. It incorporates logic that minics controller coordination and anticipation, and includes consideration of conflict resolution, aircraft speed control, overtake situation, aircraft holding and dynamic runway assignment. Operational data collected in the field were used in a model evaluation exercise. Results indicated that the model is capable of simulating real‐world aircraft operations in the terminal airspace.