Poor health among commercial truck drivers is a dangerous and costly public health problem. The high rate of obesity in truckers increases their risk for heart disease, stroke, type 2 diabetes, and some types of cancer. 1 Driver health problems, especially obesity and related conditions like sleep apnea, are related to driving errors and increased crash rates, 2–4 impacting the safety of both the driver and the general public. Although truck drivers have less than half the crash rate per vehicle mile compared with passenger car drivers, 5 large truck crashes are deadly. In 2010, there were 3413 fatalities in large truck crashes and 85% of those fatalities were passenger car occupants, pedestrians, or cyclists. 6 Annual health care costs for overweight and obese drivers are also more than $200 higher compared with normal-weight drivers. 7 Furthermore, the costs to society per fatal large truck crash averaged $7.74 million during 2009 (in 2012 dollars). 6, 8 Although obesity in trucking is a multilevel public health problem involving workers, supervisors, company policies, federal regulations, and built environments, 9 effective weightloss interventions are essential if we are to produce meaningful health and economic improvements for both drivers and society. The Safety and Health Involvement for Truckers (SHIFT) intervention is a 6-month weight-loss and health-promotion