Los Angeles’ First Diesel Buses: A Look Back At The Fleet & The 1943 Birth Of Smog January 12, 2011 Today, the Los Angeles County Metrpolitan Transportation Authority retired its last diesel bus from its fleet of over 2,200 vehicles. This historic day marks Metro’s Share:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Tumblr (Opens in new window)Click to share on Reddit (Opens in new window)Click to email a link to a friend (Opens in new window)Click to print (Opens in new window)