Abstract The objective of this survey is to cover the research in the area of adaptive traffic control with emphasis on the applied optimization methods. The problem of optimizing traffic signals can be viewed in various ways, depending on political, economic and ecological goals. The survey highlights some important conflicts, which support the notion that traffic signal optimization is a multi-objective problem, and relates this to the most common measures of effectiveness. A distinction can be made between classical systems, which operate with a common cycle time, and the more flexible, phase-based, approach, which is shown to be more suitable for adaptive traffic control. To support this claim three adaptive systems, which use alternatives to the classical optimization procedures, are described in detail. Type Technical report Year 2008 Publisher Informatics and Mathematical Modelling, Technical University of Denmark, DTU Address Richard Petersens Plads, Building 321, DK-2800 Kgs. Lyngby Series IMM-Technical Report-2008-01 Electronic version(s) [pdf] BibTeX data [bibtex] IMM Group(s) Operations Research