The House Public Works and Transportation Committee approved legislation yesterday to partially deregulate the nation's trucking industry.

The measure, which was approved by voice vote, would make it easier for new trucking companies to enter the business and for existing companies to expand.The bill also would give trucking firms more freedom to raise or lower freight rates without government approval, would limit over time the antitrust immunity that allows competing firms to set rates jointly and would pave the way for eliminating many route and commodity restrictions.

The bill wouldn't go as far toward deregulation as a Senate-passed measure but it was worked out with key senators and the Carter administration. If the bill stays intact during consideration by the full House, President Carter is expected to sign it.

Transportation Secretary Neil Goldschmidt said the bill would "inject a new competitive spirit in the trucking industry that will lead to lower transportation costs and better service." Goldschmidt made the remark in congratulating committee Chairman Harold T. (Bizz) Johnson (D-Calif.), subcommittee Chairman James Howard (D-N.J.), ranking minority member William Harsha (R-Ohio) and Bud Shuster (R-Pa) for their bipartisan effort on the bill.

Those representatives hammered out the compromise with the bill's two chief Senate sponsors, Commerce Chairman Howard W. Cannon (D-Nev.) and ranking minority member Bob Packwood (R-Ore.). Both men indicated during the negotiations that they were inclined to recommend to the Senate that the measure be accepted without a conference if it remained intact or was strengthened during House consideration.

The committee did strengthen the subcommittee-approved measure somewhat by allowing the unregulated owner-operators to carry fertilizers and other agricultural soil conditioners in addition to the processed foods they would be allowed to carry under the subcommittee bill.

The Senate bill would go much further because it would have added all food products to the raw agricultural products now exempt altogether from Interstate Commerce Commission regulation.

Several other amendments that don't alter the main thrust of the legislation also were agreed to, including one that would require the secretary of labor to maintain and publish comprehensive list of jobs available in the motor carrier industry. The amendment was an effort to give "something" to the Teamsters Union, whose leaders fear a loss of jobs with more industry competition, according to one Hill source.

"I believe we do have a very fine package," Rep. Howard said the conclusion of yesterday's session. "I think we're going forward in a very sensible way."

The hearing room yesterday was packed with lobbyists representing all sides of the issues of the complicated trucking measure.

Generally fighting hard against trucking deregulation earlier on, the regulated trucking industry recently has softened its opposition. Without guiding legislatoin, the regulated companies are worried that the ICC would deregulate trucking more substantially on its own than the legislation will allow them to.

Yesterday, Bennett C. Whitlock, Jr., president of the American Trucking Associations, congratulated the committee for "the balanced approach" it had taken in the bill.

"While we are not pleased with all of the sections of the legislation, I am gratified with the oversight provisions and the statements of the committee leadership that they will monitor very carefully the impact this legislation will have on the trucking industry . . . " Whitlock said. He added that the ATA would resist any further substantive changes in the bill.

The provision of the compromise measure that engendered the most controversy during yesterday's meeting has the potential for altering significantly the way food and grocery products have been sold and shipped, according to Hill and administration sources.

The provision, sponsored by the powerful Russell Long (D-La.) in the Senate, would allow sellers of food and grocery items who use a uniform zone delivered pricing system, to reduce prices to buyers who want to pick up their products from the seller using their own trucks.

The discounts would have to be granted to all customers and couldn't exceed the actual cost to the seller of delivery to the customer who chooses to pick it up instead.

The provision pits the Grocery Manufacturers Association -- whose food products producer-members were being represented yesterday by former DOT secretary Brock Adams -- against the Food Marketing Institute, whose members are grocery chains.

Now GMA members sell their goods largely through the uniform zone delivered pricing system, charging one price to all customers within sometimes quite large zones (such as New England) no matter what the transportation costs are.

Although GMA says abandoning the system would hurt the smaller grocers and favor the large, the grocers' group disagrees. Most of the independent grocers have formed cooperative groups that buy their goods from distributors large enough to have their own trucks, sources said.

According to administration sources, the likely effect of the provision would be to break down the current system and put downward pressures on food prices as grocers seek the lowest possible price from the manufacturers, with transportation costs added on and not included as an average for all buyers.