Labour productivity of Australian registered ships 1948-1978

This time-series analysis follows a study which measured maritime productivity indices in the period 1859 to 1919 [1] using a method developed in a theoretical model[2]. Because of the availability of data and the development of maritime technology three productivity indices were tested and specialized carrying classes included. Growth rates were significant and were predictably higher than in the earlier study.     

Potential port responses to new information systems on ships

Innovations in information technology, satellite navigation and hydrography are making it technically possible for commercial ships, run by very small crews, to be navigated in the world's seas and oceans with positional accuracies measured in tens of metres. If shipping lines do make the necessary investment in technological hardware, training, operational readjustments and data acquisition, and are also allowed to exploit the full potential of GPS, it will not be surprising if they then expect the ports to provide levels of information that allow the ships to exploit their new capabilities right up to the berth. Ports wishing to hold or improve their perceived service quality in the competitive port league will need to consider whether, and how, they can meet the shipping lines' requirements.

The introduction of strict product liability law adds a new dimension to the assessment of commercial risk in the various technological possibilities available to the ports. The possible costs involved in cases where third party data processors, software producers and electronic chart hardware manufacturers all stand between the port's data output and the user's perception and use of it, in a completely ephemeral form on a screen, need to be considered carefully. Simpler forms of data transmission, such as via traffic advice broadcast or by pilots in person may be seen as the more prudent choice in the five to ten year horizon.     

Non-Linear Dynamics of Railway Vehicles

The theoretical development of the lateral dynamics of railway vehicles has made rapid strides in recent years and many of the instabilities arising from the geometry of the wheel-rail interface and the forces acting in the contact area are now understood. In addition methods of analysis of curving and dynamic response to track irregularities have been developed and validated by experiment. This paper reviews the present status of equations of motion, limit cycle solutions for hunting oscillations and the relationship of stability to behaviour in curves.     

An Evaluation of the Accessibility Benefits of Commuter Rail in Eastern Massachusetts using Spatial Hedonic Price Functions

We estimate spatial hedonic price functions to examine local and regional accessibility benefits of commuter rail service in Eastern Massachusetts, while controlling for proximity-related negative externalities and other confounding influences. The data include 1,860 single-family residential properties from four municipalities with commuter rail service, and three municipalities without commuter rail service. We find some evidence of the capitalization of accessibility to commuter rail stations. Two model specifications suggest that properties located in municipalities with commuter rail stations exhibit values that are between 9.6% and 10.1% higher than properties in municipalities without a commuter rail station. With a third model we detect weak evidence of the capitalization of auto access time or walking time to the stations, suggesting that properties located within a one-half mile buffer of a station have values that are 10.1% higher than properties located outside of this buffer area and that an additional minute of drive time from the station is related to a decrease of 1.6% in property values. Our results also indicate that proximity to commuter rail right-of-way has a significant negative effect on property values, which suggests that for every 1,000 ft. in distance from the commuter rail right-of-way, property values are between $732 and $2,897 higher, all else held equal. At the mean sample values, this result translates into an elasticity of between 0.03 and 0.13, depending on the functional form of the hedonic price equation.     

Recursive least squares with forgetting for online estimation of vehicle mass and road grade: theory and experiments

Good estimates of vehicle mass and road grade are important in automation of heavy duty vehicles, vehicle following manoeuvres or traditional powertrain control schemes. Recursive least square (RLS) with multiple forgetting factors accounts for different rates of change for different parameters and thus, enables simultaneous estimation of the time-varying grade and the piece-wise constant mass. An ad hoc modification of the update law for the gain in the RLS scheme is proposed and used in simulation and experiments. We demonstrate that the proposed scheme estimates mass within 5% of its actual value and tracks grade with good accuracy provided that inputs are persistently exciting. The experimental setups, signals, their source and their accuracy are discussed. Issues like lack of persistent excitations in certain parts of the run or difficulties of parameter tracking during gear shift are explained and suggestions to bypass these problems are made.     

The influence of travel time variability on the value of time

Current benefits from travel time savings have only been related to the benefits from reducing mean travel time. Some previous attempts of including variability in the generalised cost function have mainly assumed commuters with fixed arrival time. This paper presents a comprehensive framework for valuing travel time variability that allows for any journey purpose and arrival time constraint. The proposed model is based on the expected utility approach and the mean-standard deviation approach. Stated Preference methods are considered the best technique for providing the data for calibrating the models. The values of time derived from the models are highly influenced by the value of travel time variability and it strongly depends on the probability distribution function travellers are faced with.     

Vehicle/Pilot System Analysis: A New Approach Using Optimal Control With Delay

This article deals with the simulation of a vehicle/pilot system experiencing external disturbances. In the simulation, the car is modeled with two degrees of freedom and the pilot is assumed to respond to the state vector with a time delay. When perturbations are introduced, the pilot is expected to drive his car back to the initial state while minimizing a quadratic cost function. With some simplifications for low frequencies responses, the model is then used to simulate the response of different vehicles to an initial step in lateral displacement. The results from the simulations are interpreted in the light of the controllability diagrams.     

The role of accident exposure in transport system safety evaluations II: Group exposure and induced exposure

Part I of this paper has argued that any meaningful evaluation of transport system safety must include a consideration of the exposure to accidents, and has demonstrated the use and limitations of several measures of exposure at intersections and along links of the network. To complement this treatment of site exposure, this part of the paper will describe the use of group exposure measures in the assessment of risks incurred by people within particular population groupings. The use of induced exposure measures is also briefly reviewed.