Although headquartered elsewhere, Fruehauf Trailer Company built truck trailers in Los Angeles. Pacific Freight Lines was based in Los Angeles. Learn more about PFL and other trucking companies of the period at http://hankstruckforum.com/htforum/index.php?topic=51570.75 .
Images: detail and full ad in Motor Transportation magazine from Ken Goudy collection
“Fruehauf Trailer Company dominated the semi-trailer industry and never had any significant competition outselling their nearest competitor by almost 80%. August Fruehauf’s motto, “Built to Last” was incorporated by the research and design team as they developed new and improved methods of transporting American goods around the world.”
Excerpt and link to extensive historical information: http://www.singingwheels.com/company-history-early-years.html .