Crosswind Sensitivity of Passenger Cars and the Influence of Chassis and Aerodynamic Properties on Driver Preferences

Results of vehicle crosswind research involving both full-scale driver-vehicle tests and associated analyses are presented. The paper focuses on experimental crosswind testing of several different vehicle configurations and a group of seven drivers. A test procedure, which utilized wind-generating fans arranged in alternating directions to provide a crosswind “gauntlet”, is introduced and described. Driver preferences for certain basic chassis and aerodynamic properties are demonstrated and linked to elementary system responses measured during the crosswind gauntlet tests. Based on these experimental findings and confirming analytical results, a two-stage vehicle design process is then recommended for predicting and analyzing the crosswind sensitivity of a particular vehicle or new design.     

An assignment principle for urban networks based on travel budgets

A new assignment principle for traveler behavior in an urban network is described which is based on empirical findings in the theory of travel budgets. It characterizes the distribution of travelers, demand, and modal split. It treats all travel decisions (whether to travel, where to go, how to get there) and the important costs (time and money) in a single, unified way. A numerical technique is proposed and it is applied to several examples to illustrate qualitative features.     

Tackling traffic congestion in Accra,Ghana: A road user's perspective

A fast emerging component of the urban transportation problem in cities of the Third World is the problem of traffic congestion. Rapid increases in car ownership coupled with poor land use planning, inadequate road space, lack of regulated parking systems, uneducated use of the road by pedestrians, and bad driving behavior of motorists have all combined to produce congestions comparable to those experienced in cities in the advanced parts of the world. Traffic management measures have been tried in some of the major cities such as road expansion and redistribution of land uses in city centers, but most have produced minimal results. It is recommended in this paper that city authorities adopt an integrated approach to congestion with emphasis on influencing the behavior of the road users.     

Application of Inverse Models to Vehicle Optimization Problems

This paper presents a nonlinear inverse model of a road vehicle which simulates combined steering and braking/driving. The inputs to the model are the lateral and longitudinal acceleration of the vehicle's sprung mass center. The simulation returns the steering wheel angle and brake/drive torques required to obtain the desired accelerations. An example is presented which demonstrates the utility of inverse models for optimization purposes.     

An analysis of seasonality of non-OPEC supply

The purpose of this study is first to find out whether quarterly averages of non-OPEC (Organization of the Petroleum Exporting Countries) supply follow a seasonal pattern. If that is mathematically established, then, second, it is attempted to estimate the best seasonal factors to decompose the forecast yearly average into quarterly averages. A set of historical data consisting of quarterly supply averages of individual countries, regional subtotals and the aggregate non-OPEC supply for the period 1973-2002 forms the basis of the analysis. The study applies Fourier analysis to quarterly supply series to test for seasonality, and provides estimates of seasonal factors for the years 2000-2002 by applying the so-called X-11 decomposition method to the historical annual averages. The accuracy of the results of the application of X-11 is then tested. It is demonstrated that the combination of the Fourier and X-11 methods provides mostly acceptable and in some cases, such as that of China, impressively accurate forecast quarterly supply averages.     

The port-routeing behaviour of short-sea ship operators; theory and practice

This paper provides an interpretation of a port-routeing pattern of short-sea shipping services which has emerged in recent years. After basic definition. a macro theory of port routeing is presented together with an examination of the business environment of operation. Greater refinement is subsequently added with reference to the behavioural characteristics displayed by a number of individual ship operating companies in port routeing as revealed by a series of in-depth interviews. Specific illustration is provided by the Great Britian-Frances market and the paper concludes by suggesting some factors to influence the development of the future port-routeing pattern.     

Spatial variations in attitudes toward expanded public transit service

Although recent budgetary considerations by the Federal govenment do not portend well for urban public transit, some transit systems are considering expansion into less densely-settled areas further from the Central Business District. Of some concern to planners has been their belief that suburban and rural dwellers may be much less inclined than urban dwellers to support expansion of transit service. This paper presents an analysis of a random-digit dialing/mail-out, mail-back survey conducted in Washtenaw County, Michigan which was designed specifically to examine differences in attitudes between urban and rural residents. Six mutually-exclusive spatial strata were established based upon population density. This paper tests for expected spatial differences in socioeconomic and demographic variables and then examines spatial variations in attitudes toward public transportation. The major conclusion is that the expected spatial variations in attitudes about transit service provision between the spatial strata do not arise. Most of the significant differences found are with respect to questions which relate to where transit is provided. Residents in rural (urban) areas support more strongly the provision of services to rural (urban) areas. Many residents, however, will support transit service that may not benefit them directly.     

Active Controls in Ground Transportation — A Review of the State-of-the-Art and Future Potential

Active control systems offer significant functional advantages over passive systems; their introduction into production-line vehicles, however, is cautious and slow. This survey describes the recent progress in the analysis, design and technology of active controls in vehicles. It includes the state-of-the-art of their introduction into operation as well as their future potential in view of recent advances in technology and computer aided design strategies. The survey has been limited to suspensions for vehicles on roads and tracks.