This report provides an overview of recent technical solution adoption rates by fleets from detailed fleet surveys. Manufacturers’ contributions in terms of technology development, cost reduction, durability and refinement will also be discussed. OEM vehicle integration and product line offerings (standard, optional, and post-production upfits) are shared. All of this background will set the stage for a review of the proposed Greenhouse Gas Phase 2 regulations, the technologies expected to be utilized to meet the targets, and the hurdles the industry must successfully clear for profitable fleet use in commercial vehicle freight transportation. Fuel efficiency has always been important to fleets and as fuel costs have risen, a plethora of fuel efficient technologies have emerged. The industry also cares about sustainability and emissions reductions and now Greenhouse Gas regulations exist to further encourage development, integration and adoption of such technologies. Recent history has shown a multitude of efficiency pathways with varying degrees of success including SCR after-treatment, 6×2 axles, electronically-controlled transmissions, trailer fairings, low rolling resistance and wide-base tires, idle reduction, alternative fuels and many more. Lab and fleet testing are challenging with a wide variety of applications, configurations and test methods. Real world results don’t always match expectations as some exceed, while others disappoint.