The chairman and the ranking minority member of the Senate Commerce Committee have teamed up to produce an unexpectedly tough legislative proposal that would alter significantly federal regulation of the nation's trucking industry.

The joint measure, to be introduced by Sens. Howard W. Cannon (D-Nev.) and Bob Packwood (R-Ore.), does not go as far toward deregulation as a measure jointly sponsored by President Carter and Sen. Edward M. Kennedy (D-Mass.). But it would make substantial changes in the way the Interstate Commerce Commission regulates trucking in an effort to make the industry more reliant on forces of the marketplace and less on regulation in its decision-making.

Make it much easier for new trucking companies to enter the business and for existing trucking companies to expand. The ICC, armed with a new national policy statement to foster competition, would not be expected to withhold new authority just because an existing carrier complained that it would lose business if a new competitor were let in.

Give trucking companies a zone within which to raise or lower rates without ICC intervention. Now, the ICC must pass on the reasonableness of all rate proposals.

Open to public scrutiny the rate bureaus used by the trucking industry to set rates that they all will charge. Much to the industry's abhorrence, the measure also would eliminate the antitrust exemption, on July 1, 1981, that allows trucking companies to set rates jointly for single-line shipments -- those in which a company picks up and delivers the goods on its own authority without the need to transfer the shipment to another company.

The measure also sets up a schedule for the elimination of restrictions that are thought to inhibit the efficient operation of companies, such as restrictions that require a trucking company to follow a specific, but circuitous route.

The ICC would be told to develop precedures to expedite applications of companies seeking to remove restrictions inorder to broaden the categories of commodities they can carry, allow them to stop at intermediate points on their routes and allow them round-trip, not just one-way, authority. The bill would ask ICC to "eliminate any other restriction that the commission deems to be wasteful of fuel, inefficient or contrary to the public interest."

The Commerce Committee is expected to hold just a day or two of hearings on the measure before moving to a markup.Sen. Cannon and key House leaders have pledged to get a measure on the president's desk for signature by June 1.