The postwar motorization boom in Western Europe implicated rising complaints about road vehicle noise. By the end of the 1960s, traffic noise abatement became an urgent topic for European regulators and automobile engineers. The article investigates how car sound, its measurement and the standardization of measurement procedures developed during the first postwar decades, and how this relates to European integration. It shows that the standardization of car noise measurement affected market integration and the harmonization of technical regulation on the European level, thus shaping the political integration process. Furthermore, standardization and harmonization stimulated the circulation of knowledge and the rise of a new field of knowledge organized around the standardized and harmonized issues. Although the standardization and harmonization efforts did not result in the homogenization of European automobile technology, they did contribute to the narrative construction of a European car identity.