Current emissions control legislation requires significant reductions of particulate emissions from light duty diesel engined vehicles in California for model year 1986 and Federally for model year 1987. In addition, NOx emissions levels will be reduced. This compounds control requirements due to the inverse relationship between NOx and particulate emissions.To meet these standards, a catalytic trap oxidizer (CTO) based on a radial flow metal mesh filter was developed for use as an after-treatment device on light duty diesel vehicles. A complete system for assisted regeneration was devised to enable this unit to operate without blocking during all normal driving modes. The integration of the catalyzed trap and regeneration system with the vehicle to provide a practical system for the reduction of diesel particulate emissions is discussed.To date, many prototype catalytic trap and regeneration system installations have been completed on various test vehicles, both naturally aspirated and turbocharged. The operational conditions and test results from a selection of these studies will be presented. Special emphasis will be placed on the ability of the system to perform assisted regenerations, thus enabling automatic operation over the normal in-service driving modes that light duty vehicles encounter.