This paper presents the experience gained by testing a trap system on a turbocharged bus engine. The trap is placed before the turbo in order to fully exploit the high regeneration potential of the turbocharged engine. This of course necessitates a new consideration of the turbocharging system, in order to keep a good turbocharger response. The quick temperature response of the light-weight exhaust manifold installed with the system, partially offsets in this respect the thermal inertia of the ceramic trap. The effects of the use of Cerium or Copper-based fuel additives enhancing regeneration capability are presented, in order to allow preliminary assessment of optimization capabilities for the final version of the system to be used with the bus. Regeneration of this system is effected through the application of exhaust throttling before the trap. The bypass technique is also applied for trap protection. Testing on the engine test bench confirmed trap and regeneration system effectiveness and on-road testing with an experimental bus is now under way.