ROLE OF THE COMPUTER IN HIGHWAY DESIGN. SINO-BRITISH HIGHWAYS AND URBAN TRAFFIC CONFERENCE. PAPERS PRESENTED AT THE CONFERENCE HELD IN BEIJING 17TH-22ND NOVEMBER 1986

This paper discusses various techniques by which computers can aid the design of roads. One of the requirements is a full three-dimensional model of the road design surface; the ability to produce such models from survey and design has several clear advantages. Based on experiences of using rectangular grid, random point, and triangle methods for modelling terrain with early computer systems, new 'string modelling' techniques evolved; a 'string' is a series of three-dimensional coordinates, joined by curves or straight lines. String modelling can be applied to both existing surfaces and new road works, and its seven significant advantages are presented. Various other aspects of computer-aided highway design are then discussed, including: (1) analysis; (2) visualisation; (3) contract information; (4) the user interface; (5) links to other systems. By introducing high levels of automation, such design offers the potential for increased productivity, and greater accuracy and quality of the end product, which are guaranteed by the algorithms used for calculation of geometry (areas, volumes, and contours) and the procedures used for producing drawings. In the future, the trend will be to store more road information within the model data base, rather than in drawings; in the authors's view, the major area for development is not the extension of drafting facilities, but the development of more design and analysis facilities to provide engineers with a greater range of possibilities. (TRRL)