Trucking deregulation occurred between 1978-1980 during the Carter administration.

Plus, the way it was regulated makes modern regulatory capture look consumer friendly. If you wanted to start a trucking company, you had to submit a business plan with a list of committed customers and already set in stone pricing. The Feds would literally hand your plan to everyone with a route in the region, give them a few months to review it and then your potential competitors got to vote on whether you should be allowed to operate that route. Predictably, it was basically just outsourced sales for the exiting companies.