ABSTRACT
The selection of the optimum horizontal and vertical alignment, to enable the preparation of the above documentation, requires good engineering judgement following a detailed examination of a number of alternative alignments which allow for the site's constraints and the application of design standards appropriate to the road type. The end objective is to have a 'flowing' alignment that is attractive to drivers whilst also being economical to construct and protective of the environment in which it is located. Much of the work involved in comparing alternative alignments involves repetitive manipulations of detailed levelling and earthworks data and this is now done with the aid of the electronic computer using, in the UK, sophisticated computer-aided design (CAD) packages1 such as the British Integrated Program System for Highway Design (BIPS) and the MOSS (an abbreviation of MOdelling SyStems) packages.
