Diesel Technology - Transportation Trailer Technology Download as PDF OPTION V – TRANSPORTATION TRAILER TECHNOLOGY SHORT-TERM CERTIFICATE – Guided Pathway/Map Item # Title Credits DEM 113 Trailer Maintenance and Inspection 3 DEM 121 Trailer Air Brakes and Suspension 3 DEM 136 Trailer Electrical System 3 DEM 175 Trailer Structure Repair 3 Sub-Total Credits 12 Total credits: 12 Overview Program Diesel Technology Type Short-Term Certificate