Discussion on Methods of Traffic Routes' Alignment Survey and Application of Principle of Least Squares

Traffic route's alignment survey is among the important works required in location survey stage. This paper concisely introduces both conventional and contemporary techniques of traffic route's alignment survey. It also analyzes and discusses the question that while traffic route's alignment survey is being conducted by conventional diagrammatic method (or called offset method), how to improve the accuracy of diagrammatized centerline stations' coordinate parameters for staking-out by the principle of least squares to reduce the workload of repeatedly threading, checking on and adjusting the laid-out centerline stations. Finally, the authors draw the conclusion that the laid-out traffic route's center line stations based on staking-out coordinate parameters obtained by the principle of least squares are able to satisfy the required tolerance of location survey of traffic route's centerline stakes. © 2009 ASCE.