David Millis, president of Millis Transfer and a director at Heartl Express, has been speaking publicly about his personal shift away from car dependency. In a September 2024 talk, Millis and co-speaker Robbie Hobein described their "accidental journey" to becoming "mostly car-free," which they said began with the question "can we carry kitty litter on a bike?" Millis stated that the household sold its pickup truck, added two e-bikes, and that the remaining car "mostly gathers dust." He claimed the family saved at least $40,000 and "significantly reduced" their carbon footprint, and said they are "noticeably happier." Millis cited studies suggesting that owning and operating a vehicle costs about $112,000 per year versus "a few hundred bucks" for an e-cargo bike, and that if every household in Denver retired a car, 4 million metric tons of carbon dioxide could be saved annually. He also described his background in a separate appearance, noting he worked in financial services for more than 30 years, qualified as a chartered accountant, and led Deutsche Bank's European and India loan operations teams.