This paper discusses the fact that vehicle and powertrain test methods have long been guided by type approval requirements – with a focus ot the recent/current example of real driving emissions (RDE) and in-service conformity (ISC) test requirements. The implcations current and future – of these testing requirement, which force the use of portable emissions measurement system (PEMS) are discussed. In this context, BOSMAL Automotive Research and Development Institute’s PEMS systems are presented, and the systems’ attributes and versatility are explored. Considerations for testing a very wide range of vehicle, engine and fuel types are mentioned. Non-legislative applications of PEMS systems are briefly explored; finally, it is shown that the emissions laboratory and its chassis dyno remain indispensable when conducting work on light duty exhaust emissions, even in the era of RDE.