On February 1, 1979, the EPA published proposed rules regulating particulate emissions for light-duty diesel vehicles. Questions both internal and external to EPA concerning the practicality and necessity for these requirements resulted in the initiation of a testing program. The test data was run according to the proposed Federal Register requirements for both FTP and HFET cycles. The two test vehicles were a 1975 Mercedes Benz 300D and a 1979 Oldsmobile 350 CID Diesel. Five different configurations of exhaust collection hardware were tested. The two vehicles were tested twice in each configuration. Previous testing programs had established a baseline particulate emission number for each vehicle. All of the individual FTP and HFET tests results are tabulated. The average FTP and HFET results for each configuration were calculated and compared to both the baseline data average, if available, and to the average result of this study. No baseline HFET data was available. In conclusion, there appears to be direct correlation between collection configurations and mass particulate emissions.