Who's union union represented?

ABF is union.
Cassens is union

 

there are a lot of smaller regional and local companies that are teamsters. ltl freight, dump trucks, cement trucks, tanker, and grocery/food delivery are the big one for the teamsters anymore, not much in otr truckload.

there are a few companies that are union, but not teamsters. NEMF (new england motor freight) is IAM, the machinists union.

ACC in Michigan, Ind, and Ohio is UAW, and is the in house carrier for GM parts in between plants. Chrysler and Ford also have similar operations.

 

The Teamsters is the one for trucking, but there are a lot of other unions. AFL-CIO, UAW (United Auto Workers), UMW (United Mine Workers), NEA (National Education Association), IBEW (International Brotherhood of Electrical Workers, Longshoreman's Union, and don't forget about the Postal Workers or those other public workers unions. I don't recall the names of the last two.