Transport problems as perceived by inner city firms

The role of transport policy in assisting inner city firms is still unclear. This paper raises several important policy questions and reviews the findings of past research, which suggest that transport problems are a major irritant to inner city firms but are unlikely to cause them to leave the area, and that the ability of transport improvements to attract new firms is uncertain.It describes and presents the results of a recent study designed to determine the effect of transport problems on manufacturing and service industries, whether such problems are more serious in the inner city, and which solutions would be most appropriate. The study involved a series of detailed case studies of inner and outer city firms in Leeds and London. It identified as the most serious problems, congestion, public-transport problems, parking shortages and on-site delays for commercial vehicles. Similar problems arose in all areas, but were more severe in inner than in outer areas, and in London than in Leeds.The most common effect was lost time, but reduced efficiency, lost business, staff dissatisfaction and recruitment problems also occurred. Management had difficulty costing the effects of such problems, and often overlooked those incurred by others. The problems were, for the most part, local or site-specific, and are likely to be amenable to low-cost solutions. However, congestion and parking problems in inner London appear to merit area-wide treatment.A series of recommendations is provided for policy-makers.Further details of the study reported here are contained in a series of working papers which are available from the Institute for Transport Studies, University of Leeds.     

The loss of a jack-up under tow

The events leading up to the capsize and total loss of a jack-up under tow are briefly summarised. The investigation of the causes of this are described in some detail. It involved model tests, finite element analysis, stability calculations, a determination of motions by analysis of newsreel videos taken at the time and close examination of an underwater film taken of the wreckage.

The likely sequence of structural failures leading up to the capsize is established. These are summarised and the lessons learnt from the enquiry highlighted.     

The Application of Linear Optimal Control Theory to the Design of Active Automotive Suspensions

Some linear stochastic control theory relevant to the design of active suspension systems subject to integrated or filtered white noise excitation is reviewed, and application of the theory to a particular problem is considered. The problem considered is the well known quarter car problem in which a control law which minimises a performance function representing passenger discomfort, suspension working space, and tyre load fluctuations is required. With full state feedback, the requirement for a formulation of the problem which leads to the system under consideration being observable and controllable is referred to, and it is shown how a well known coordinate transformation enables this requirement to be satisfied. With limited state (or output) feedback, problem formulations which will avoid potential numerical problems in deriving the optimal control are described. Example solutions are included in order to illustrate the methods.     

Urban transportation and decision making — A comparison of three case studies in Britain

In spite of the impacts that new transportation facilities have upon the economic, social and political structures of established urban areas, the decision process leading to policy formation and plan implementation has received little, if any, attention. Case studies of three County Boroughs in Britain having different urban transport policies suggest that the decision making process is dominated by groups and individuals who attempt to implement policies which benefit the sectional interests which they represent. Within a changing relevant environment, local technicians, politicians and community groups compete and form coalitions in order to acquire authority and implement their own notions of justice and equity in the adaptation of the built environment.     

On the practicality of the UNCTAD 40-40-20 Code for liner conferences

The potential effects of a rigid adherence to the UNCTAD Code are analysed for 26 developing countries. A brief commentary is given on the advantages of a more liberal application of the Code, including reciprocal sharing of liner tonnages by regions of developing countries with regions of developed market-economy countries.     

The capacity of a priority intersection

We present simple formulae for the maximum capacity of an intersection of a single stream of minor traffic with a single stream of major (priority) traffic. The method allows for both mixed (nonhomogeneous) vehicle types and for inconsistent driver behaviour in the minor traffic stream. For a realistic class of major headway distributions the capacity is the harmonic mean of the capacities for each individual vehicle type. The formulae include generalisations of Tanner's formula for the cases of inconsistent and/or nonhomogeneous minor vehicles.     

Off-Road Vehicle Dynamics

Recent developments in off-road vehicle dynamics are reviewed. Progress on this topic and the application of new techniques to the particular problemsassociated with off-road operation tend to lag behind practices established for road vehicles.

The factor which limits further progress is the lack ofappropriate off-road tyre data, in particular, on vibrational and lateral force generation characteristics. Also, a long term study should be aimed at understanding the dynamic behaviour of tyres on yielding surfaces.