These regulators have to date taken no legal action against any of the carmakers or taken forward more in-depth investigations to scrutinise whether the models used illegal defeat devices despite strong evidence that they did, including: inappropriate use of a ‘thermal window’ (29 models); high ‘hot restart’ emissions (23 models) and plain shut-offs after a certain time (at least one model). Urgent action is needed by national agencies (TAAs) to investigate these suspect emissions control strategies.