CCJ parent Randall Reilly earlier this year, in partnership with Shell Lubricant Solutions, produced the 2022 State of Diesel Technicians report, a survey-based analysis of the current state of the diesel technician trade. Survey participants were current technicians across many industrial segments, including trucking and transportation. The survey itself reveals what technicians want most from prospective employers; why they change jobs; the kind of training methods currently used by their employers; and how much money they make; among many other insights.
It's one of the deepest dives you will find on this part of the labor force and it is available for download at no cost.
