The District's Taxicab Commission has substantially increased fines for infractions by cabdrivers, revamping its rules for the first time since its formation in 1987.

The new fine schedule, which in one instance raises the penalty for uninsured drivers from $5 to $500, is intended to make it prohibitive for operators to ignore the rules. The penalty for rejecting a request for a ride, for example, has risen from $10 to $250.

The commission also has instituted new regulations, including one that requires drivers to keep cabs clean and another that makes it illegal for drivers to smoke while transporting passengers. Drivers violating either rule will face a $25 fine.

"Ninety percent of the taxicab drivers that we have in the industry will obey our rules, so the fines, therefore, should be of no concern to them," Carrolena M. Key, the commission's chairwoman, said yesterday. "But those drivers that disobey the rules of the city, we believe should be vigorously sanctioned."

Unlicensed drivers have always run the risk of arrest because they violate District law, but that provision has never been enforced because it was never in the commission's rules. That has changed, and now an unlicensed driver can face imprisonment and a $500 fine, said George W. Crawford, the commission's general counsel.

The new fine schedule went into effect June 1, although the commission has established a grace period while its computers are programmed. Key said taxi drivers found in violation may begin paying the new rates as early as next week.

There are 8,555 licensed cabdrivers in the District, and a few who were interviewed yesterday objected to the stiff penalties. Although all agreed unlicensed drivers should be severely penalized, none agreed with the commission's overall performance.

Cabdrivers have long complained that the base fare is low, and several said the commission's reluctance to raise it shows it does not have their interests in mind.

"They give us a hard time. Everybody knows," said one cabdriver who did not want his name used.

Cab companies do not stand to suffer under the new fine schedule because it is the drivers themselves who are liable. Still, the owner of one of the largest cab companies in the District said the fines were too severe.

"I think some of them are a little too dramatic, a little bit out of hand," said Jerry Schaeffer, the owner of Liberty Cab. "Fines are a good thing and there is a place for them, within reason."

The minimum fine is now $25, up from $5. Failure to display identification rises from $10 to $50 and failure to keep a daily record of transports rises from $10 to $100.