A one-time Bowling Green, Ky., lawyer was sentenced in federal court here yesterday to serve three years in prison and fined $10,000 for twice obstructing proceedings of the interstate Commerce Commission.

Robert M. Pearce, who was a lawyer for 28 years until he resigned from the bar, pleaded guilty last month to charges that he led a scheme to create two dummy trucking firms so that he could obtain operating rights from the ICC for them and then, along with others, sell those rights for a total of $450,000.

Pearce asked U.S. District Court Judge Barrington D. Parker for probation in the case, but the judge told him that "of course you recognize you have completely turned your back" on the oath he took as a lawyer to uphold the law.

Parker ordered Pearce to pay the $10,000 fine by Dec. 4 and report two days later to the Federal Correctional Institution in Lexington, Ky. Parker said that Pearce, an admitted alcoholic, probably eventually would be sent to hospital correctional unit at Marion, Ill. he will be eligible for parole in a year.

According to the criminal information he pleaded guilty to, Pearce concealed his partial ownership of the two dummy trucking firms, Cape Air Freight Transporters Inc., which won the lucrative ICC operating rights.

Pearce then got other attorneys and aides to file protests of the operating rights on behalf of competing trucking companies, according to the criminal information. But the competitors did not know about the filings.

At the same time, Pearce had papers filed on behalf of Cape Air supporting the dummy firm's operating authority. In the Air Freight case, he had the bogus protests from the competitors withdrawn. By such actions, Pearce was able to solidify his ICC operating rights.

Later, the Cape Air route rights, which encompassed the eastern half of the U.S., were sold for $295,000, while the Air Freight rights in Tennessee and Kentucky were sold for $155,000.

Pearce told Parker that he deserved probation because he had to fight his alcoholism "on a 24-hour basis. I've lost my livelihood. I've been disgraced in my coummunity."

But Assistant U.S. Attorney William D. Pease said that Pearce, 59, "does not deserve probation because of his illness. he deserves incarceration because of the crime he's committed.

"He violated his clients' interest for his own personal profit" by having the bogus complaints filed with the ICC about Cape Air's and Air Freight's operating rights, Pease said. "It was since 1969 that Mr. Pearce was conducting a detailed, meticulous fraud.

Earlier, Parker fined William R. Bennett, a one-time trucking executive from Elizabethtown, Ky., a total of $1,100 in connection with his role in the Pearce scheme, Bennett, 44, had pleaded guilty last month to two counts of filing false statements with the ICC and one count of making false pretenses to the ICC. He also was placed on probation for two years.