The report describes work carried out on a research study to develop methods of generating, collecting, and analyzing particle emissions from automotive power plants by means sufficiently accurate and reproducible to allow the determination of the effect of fuel additives, fuel composition, engine and vehicle operating mode, and advanced emissions control hardware on exhaust particle size, concentration, and composition. Particle emissions were examined from several different engines, loaded by an engine dynamometer, and several different vehicles operated under cruise conditions, the FTP (California) cycle, and the LA-4 cycle. Particle mass measurement techniques have included tailpipe measurement methods and air dilution sampling methods using impaction separators, filters, a Beta-guage technique, and piezoelectric crystal techniques. The applicability of the techniques to cycled vehicle studies has been shown.