Transport Planning in a Multi-resource Context: The Morecambe Bay Barrage†

The paper describes work done by the Mathematical Advisory Unit of the Ministry of Transport to derive the net transport value of a Barrage across Morecambe Bay, as a contribution to the assessment of non-water benefits made by an Economic Study Group under the aegis of the Department of Economic Affairs' North West Regional Office. The basic method was to establish a traffic model which could represent traffic movements on the road network of north Lancashire, Westmorland and west Cumberland, to use this model to predict the traffic consequences of a road-bearing Barrage (and a number of other projects in combination), and to estimate the economic benefits accruing from these different alternative networks.Problems which arose in establishing the net value of the Barrage included the strong interdependence of the benefits to the Barrage on the possible existence of other projects such as the Arnside Link and the Duddon estuary crossing (and vice versa), the budget constraint for road building in the Ministry of Transport, which has the effect of raising the criteria for road projects above those normally required for other public sector investments, and the timing of other projects on the worthwhileness of the Barrage. The effect of tolls was studied also.Under certain assumptions about other planning decisions, the gross transport benefits of the Barrage were estimated to be £24·5m, in present-value terms calculated at 8 per cent to 1981. An investment of £6·6m was required, in link and approach roads, to yield this benefit. The net present value at 1981 is thus about £18m. In view of the Ministry of Transport's budget constraint, a figure which more appropriately represents the value of the Barrage as a road-bearing structure, given other road projects on which money might be spent, is £24·5m £ 2·5 less £6·6m, which is £3·2m.     

Slip flow in the hydrodynamic entrance region of a tube and a parallel plate channel

Summary The problem of slip flow in the entrance region of a tube and parallel plate channel is considered by solving a linearized momentum equation. The condition is imposed that the pressure drop from momentum considerations and from mechanical energy considerations should be equal. Results are obtained for Kn=0, 0.01, 0.03, 0.05, and 0.1 and the pressure drop in the entrance region is given in detail.Nomenclature A cross-sectional area of duct - c mean value of random molecular speed - d diameter of tube - f _p - f _t - h half height of parallel plate channel - Kn Knudsen number - L molecular mean free path - n directional normal of solid boundary - p pressure - p ₀ pressure at inlet - r radial co-ordinate - r _t radius of tube - R non-dimensional radial co-ordinate - Re _p 4hU/ - Re _t 2r _t U/ - s direction along solid boundary - T absolute temperature - u velocity in x direction - u* non-dimensional velocity - U bulk velocity = (1/A) _A u dA - v velocity in y direction - x axial co-ordinate - x* stretched axial co-ordinate - X non-dimensional axial co-ordinate - X* non-dimensional stretched axial co-ordinate - Y non-dimensional channel co-ordinate - eigenvalue in parallel plate channel - stretching factor - eigenvalue in tube - density - kinematic viscosity - i index - p parallel plate - t tube - v velocity vector - gradient operator - ² Laplacian operator     

Tackling the Challenge of the Nineties

In this annual Blackett Lecture the experience of pursuing the challenge of rational planning and decision-making in London Transport is discussed. Secondly, some of the major challenges affecting all large business organizations in the 1990s are described. Thirdly, the characteristics which enable organizations to respond effectively to these challenges, and which help ensure their survival and success, are delineated.