A 1.0L underfloor converter of a 1.4L PZEV calibrated vehicle was replaced by a 1.26L HC trap and a 1.26L SCR catalyst. The HC trap consisted of a zeolytic storage layer beneath a three-way catalyst layer containing Pd/Rh. The HC trap was followed by an SCR catalyst for NOx clean-up. The production close-coupled catalyst and replacement underfloor catalysts (HC trap and SCR) were aged on a combination of rural and highway roads for 150,000 miles. Peak temperature during road aging of the HC Trap and SCR catalyst were approximately 600oC. Vehicle FTP and US-06 tests were conducted at 9 intervals between 2,000 and 150,000 miles. In general, the FTP emissions did not change significantly with mileage. At 150,000 miles, nMHC and NOx emissions were 6 and 14 mg’s/mile, respectively. US-06 nMHC + NOx emissions were consistently below 10 mg/mile. At 150,000 miles, the HC Trap reduced HC and NOx emissions by 6 and 19 mg/mile, respectively. Due to the effectiveness of the HC trap on this application, the SCR had no significant impact on HC emissions, and a small benefit for NOx.