Intelligent Speed Adaptation (ISA) is a system by which the vehicle "knows" the permitted or recommended maximum speed for a road. The standard system uses an in-vehicle digital road map onto which speed limits have been coded, combined with GPS options if desired. ISA can take various forms of interventions, such as advisory, voluntary or mandatory; the speed limit information can be extended in line with prevailing local conditions. Main tasks of the project involved investigating driver behaviour including overtaking; looking at ISA designs for motorcycle and large trucks; investigating costs and benefits of ISA. Core issues of investigation included likelihood of behaviour change over the long term; possibility of some manoeuvres becoming more dangerous with ISA; usage patterns; and practical issues. The report covers all the major aspects of the project work including field trials, on-road trials, test-track trials, simulator study, implementation scenarios examining accident reduction potential and the costs and benefits of ISA.