Duaine Conrad climbed into the driver’s seat of his cabover Mack, 300 horsepower under the hood and five speeds at hand. It was sometime in the mid-’80s — the exact year escapes him — he was 23 years old and had agreed to fill in for a driver who called in sick. It was his first run for Filippo & Sons, a trucking company based in Plymouth, Wisconsin.
Not surprising, he was hauling cheese that day. At the time, Plymouth was home to the National Cheese Exchange, and the city still takes pride in...