If I'm not mistaken, both are refrences to 18 Wheels of Steel, the former is obvious and the latter was also a company in Haulin'/ALH, or at least a very similar one.

IWM Waste, a.k.a. Western Wastes.

Yes, that one! Although, I wish that instead of 18 Wheels Garage they brought back some more 18 WOS companies, like Amergine (iconic), United Fuel and Oil (for it's abbreviation and Texas location) or Dig Witch Ltd. (as a rival to Bitumen).

Or maybe even Capone International from HT, because the Al Capone refrence is just funny.

Dig Witch is too similar to Ditch Witch, a real life construction equipment company.