LinSig was first written in the mid-1980s as a DOS-based tool for analysing and optimising single traffic signal junctions.

This version also introduced graphical diagrams into the software showing information such as the junction's lane layout and the phasing and staging arrangements.

[7] LinSig uses a development of the Cyclic Flow Profile traffic model which has been used extensively in the UK for many years.

LinSig optimises signal timings either to maximise traffic capacity or minimise delay at a junction.

It is designed to model small groups of junctions in detail rather than larger networks covering entire towns.