A combination instrument panel or cluster is classified according to its principal function or, under the combination-goods rules, by the component that gives it its essential character. If the speedometer or tachometer is the principal element, classification under 9029 is supported. However, a fully integrated dashboard assembly may be classified as a part of a vehicle under the vehicles chapter. The degree of integration and the article's design purpose are the determining factors, and a binding ruling is advisable for complex assemblies.

A tachograph that records data goes beyond the simple speed-measuring function of a tachometer and may be classified under the recording instruments provisions of another heading rather than under 9029. The classification depends on whether the recording function or the speed-measuring function is principal. Importers of digital tachographs used in commercial vehicles should verify the applicable tariff line, as the recording capability can shift classification.